Historic, archived document Do not assume content reflects current scientific knowledge, policies, or practices. U.S, DEPARTMENT OF AGRICULTURE, BUREAU OF ENTOMOLOGY— BULLETIN No. 58, ' _L. O. HOWARD, Entomologist and Chief of Bureau. ME INSECTS INJURIOUS TO FORESTS, [. THE LOCUST BORER. By A. D. HOPKINS, In Charge of Forest-Insect Investigations. IL THE WESTERN PINE-DESTROYING BARKBEETLE, By J. L. WEBB, Special Field Agent, Forest Insect Investigations. TIL. ADDITIONAL DATA ON THE LOCUST BORER. gs By A. D. HOPKINS, In Charge of Forest Insect Investigations. IV. THE SOUTHERN PINE SAWYER. | By J. L. WEBB, M. S., Agent and Exper. ¢ 3 INSECT DEPREDATIONS IN NORTH AMERICAN FORESTS AND PRACTICAL : METHODS OF PREVENTION AND CONTROL. ; WASHINGTON: GOVERNMENT PRINTING OFFIOB. Ene £9t0u: S ees, DEPARTMENT OF AGRICULTURE, BUREAU OF ENTOMOLOGY— BULLETIN No. 58. L. O. HOWARD, Entomologist and Chief of Bureau. SOME INSECTS INJURIOUS TO FORESTS, I. THE LOCUST BORER. By A. D. HOPKINS, Jn Charge of Forest Insect Investigations. I. THE WESTERN PINE-DESTROYING BARKBEETLE. By J. L. WEBB, Special Field Agent, Forest Insect Investigations. Il. ADDITIONAL DATA ON THE LOCUST BORER. By A. D. HOPKINS, In Charge of Forest Insect Investigations. IV. THE SOUTHERN PINE SAWYER. By J. L. WEBB, M. S., Agent and Expert. VY. INSECT DEPREDATIONS IN NORTH AMERICAN FORESTS AND PRACTICAL METHODS OF PREVENTION AND CONTROL. By A. D. HOPKINS, Pu. D., In Charge of Forest Insect Investigations. UR I mr he fit ih me a0 hie! ip © G nat fe ¢ == MS ts 5 fe Hit 9 =k — % = = th i al il WASHINGTON: GOVERNMENT PRINTING 1910. OFFICE. Tee eee ch oa “ 7 EIS RTT TS ET EEE SS OG yout 7 oS eaters Barge ad PILL PALTRY TAREE BUREAU OF ENTOMOLOGY. L. O. Howarp, Entomologist and Chief of Bureau. CG. L. Maruatt, Assistant Entomologist and Acting Chief in Absence of Chief. R. 8S. Cureton, Executive Assistant. W. F. Tastet, Chief Clerk. 2 HeC . D. Horxtins, in charge of forest insect investigations. sD: M. WEBSTER, in charge of cereal and forage insect investigations. ie QUAINTANCE, in charge of deciduous fruit insect investigations. . F. Putiurres, in charge of bee culture. D. M. Rogers, in charge of preventing spread of moths, field work. Roa P. Currig, in charge of editorial work. MABEL Co.LcorD, librarian. Forest INSEcT INVESTIGATIONS. A. D. Hopxins, in charge. H. E. Burke, J. L. Wess, Jos—EF BruNNER, 8..A. RoHWER, T. DovENErR,2 W. D. EpmMonstTon, agents and experts. W. B. Turner, special agent. Mary E. Faunce, preparator. Hunter, in charge of southern field crop insect investigations. HITTENDEN, in charge of truck crop and stored product insect investigations. E. Snyper, W. N. Witi1aM Mippieton, Mary C. JoHNsoNn, student assistants. @ Transferred to another branch of the bureau. II ° LETTER OF TRANSMITTAL. U.S. DEPARTMENT OF AGRICULTURE, BurEAU OF ENTOMOLOGY, Washington, D. C., August 5, 1910. Str: I have the honor to transmit herewith, for publication as Bul- letin No. 58, five papers dealing with insects injurious to forests and forest products. These papers were issued separately during the years 1906 to 1909. Part I, ‘‘The Locust Borer,” by A. D. Hopkins, comprises a sum- mary of information from published accounts, supplemented by data secured by recent investigations, and deals more particularly with - practical methods for controlling this, our most important enemy of the black locust. It is designed to be of service to owners of planta- tions and forests, as well as to investigators, in the prevention of injuries to this useful tree. Part II, ‘‘The Western Pine-destroying Barkbeetle,’ by J. L. Webb, has special reference to the results of investigations by Mr. Webb in central Idaho in 1905, but relates also to the results of other investigations and to available information on the insect and methods of controlling it. Part III, ‘‘ Additional Data on the Locust Borer,” by A. D. Hop- _ kins, comprises a partial revision of Part I and gives additional infor- ~ mation based on the results of investigations carried on since that _ part was issued. | Part IV, ‘‘The Southern Pine Sawyer,” by J. L. Webb, gives the — results of special investigations by Mr. Webb and relates to a sub- ject of much economic importance to the timber interests of the - Southern States, and especially of sections in which the pine timber is damaged by storms. The results of these investigations and the information contained in this paper make it possible to avoid a large percentage of the losses from damage by the sawyer, which have here- _ tofore seemed inevitable. Part V, ‘‘ Insect Depredations in North American Forests and Prac- _ tical Methods of Prevention and Control,’’ by A. D. Hopkins, gives a summary of facts, conclusions, and estimates relating to the forest- insect problem as applied to North American conditions and calls attention to its importance in the future management of private, Il ee FY CPO HS PORE Dik TRS ie tle a ay Oe hate SOS EE EEE PI, LN es AP OS PYLE T PPR I ae Te Ha OYA TREN sche Ta CAO RIE FX IV LETTER OF SUBMITTAL. state, and national forests. The matter is presented in as brief and concise a form as possible, in order that the information may be readily available to the general reader, as well as to the forester and student, and references are made to publications in which more detailed accounts may be found. The statements and conclusions relating to the insects and their work and to methods for their con- trol are based almost entirely on investigations and observations by Doctor Hopkins and by assistants in the Bureau of Entomology working under his direction, carried on in all of the principal forest areas of the United States. Respectfully, L. O. Howarp, Entomologist and Chief of Bureau. Hon. W. M. Hays, Acting Secretary of Agriculture. CONTENTS" Page. ane locust borer (Cyllene robiniz Forst.).......-.--.:.------. A. D. Hopkins... : ee eNO R te ct te ene ak oe Napoli «bia see es es ee - meomomic tmporance. of the tmeect:....-.2.. 22254205 5-+-2+-- nee ees ee 1 i ane ge eR Ne A a a tame Be ok ew ae ce a aeibs 1 Character of the insect and its work Ree eee ae ee eae nn a eS aah 2 Petr CMI OL MOHS meen es Sarasa oan oie ois ane ooo own me 2nd 3 oserpaliites Gn preventing 1osses),.2.. 2.2 302-2 2--sec2G +222 ede eee e ees 3 rireee ere terOnOGs Wee ene en ti Sane ee eos wise baw sa gene 3 Observations by the writer,1890-1905.2. 022.2522 5-22.- eee et eet. 7 Observations hy members of the Forest Service.......-...--------+--+--- 9 ecempOpeervawOne pW tae WII: 222.0 ie ode e ween debe esse eo eee 22 9 Suggestions for controlling the insect and preventing losses.......-...-..-- 11 Suggestions for propagating borer-resistant trees...........--.--- SS eee ee 13 iapieations xelating to the locust borers... 2-.-.:.-.-...-o-----s-0-45- 15 The western pine-destroying barkbeetle (Dendroctonus brevicomis Lec.), ds EWebo 17 Rea MORIRTORIOE re re Ae Be te eae nt Gan Se fe welsh dees KE ee Lz Death of the pine caused by the western pine-destroying barkbeetle. .. . 18 iaeter OL ine impech and iis: WORK. ...!. 5205... -225.s).-.52 ise cee dane 18 Pastribution-...... Ee ee wR NS a ee hos Siti BY Lalas dia oe 19 Prien an chamlare AMCs LOSKOS 2 ae ics hs Ss ok js Beeld ke Ge oS 6 oe ee 19 Perio ites Gn pkeventine losses. 9. 2.42 1 So ne aie ha abe ue ee we 20 Early history of the species...........- eros KAA a ORAS Ss Stan ue 20 mneervations/ by Hopkins, 1899-1904) i. 65. isda eee ee ee ees see 21 memnalons py tl. We Burke, M004). 2 cle. cos oss die she 52 vena bees 23 Deon AMORA Oy Ee Mp Lters MOQ oe foes ann cesta o a sens -es eed ad nee 23 iviemistonnandung pital the insects.'.<. 5-3... -.<) .206 4.8.04 5--28% 23 Seats CN RIN Seyret ty Agr ene ya his ois, ware Scher a waite: {425+ e2ee- ee Insects in their relation to the reduction of future supplies of timber. - Interrelations of forest insects and forest fires.................-.-....-. Losses from forest insects! . /ss22 23 eace. eee ee Insect-killed timber as ‘fuel for firessi3s sep ee ene Fire-killed timber injured by imsectsee ss aeeee eee Destruction of imsects by fire: 2.25 ee Durability of insect-killed timber.......-. ara SEI ta BUN, cel Interrelation of forest msects and foresthumeis- == sees e ee Decay following injury by insects. . oe Summary and estimates relating to eee endl scien ai Gaeeet Standing timber killed and damaged by insects..-.-....-......-- Reduction inthe Nation’sqwealtha2.: 222-222 see Reduction incash revenuies/2: 2522202 Sane 5 ae oe eae Reduction in value of finished and commercial products. ....... Methods of prevention and control..........-..- “a ssa re ee ee General principles of control j22-22.22220- = eee Control of barkbeetles which kill treesi-2 == 24> =25= ease. 22 eee Control of insects which cause defects in living timber......----...-- Prevention of injury to dying and dead trees.......-.---------.----«- Prevention of loss from insect injuries to natural and artificial repro- duction... ls..i055.2 336.6 2 ie Prevention of insect injuries to forest productss3a9-2 5455-4 4eeee ee ee Utilization of natural enemies and factors in the control of injurious insects Elementary and technical knowledge of forest entomology for the forester Conclusion ./...2./. 2.22 .0.¢2.4.2222 222. General estimates of amount of damage caused by forest insects How losses'can be prevented... 1.222 9922 Publications relating to forest insects i ee ee AO =) wee) (eas) ow eels oe ae «ele eo a = oe eee) ose em) me @ fe) a) oe fm, wl wim) ow fe ml me feel fest ey se es ee ele at 7 ILLUSTRATIONS. PLATES. Page. Pxuate I. Work of the locust borer (Cyllene robimz)..................--..---- 2 II. Work of the western pine-destroying barkbeetle in bark, removed from killed tree; also faint marks on surface of wood...........-.- 18 III. Work of the western pine-destroying barkbeetle, removed from killed ee ere re OP Se ne a Sio eS alge aie odin wader bee 18 TEXT FIGURES. feet tne. locust borer (Cyllene robinew): Tharva....02..........2-22.-2 520252 2 2. The locust borer: Eggs, larvee from hibernation cells. ...........-..-- 3 a2 Ane 10cust. borer: Male and female beetles... .-.....2..-..2. 220i... 4 ems MOCIISE WOTEr? UWA. Sci So opis <5 tae ale oe tees ees cee ss ee A 5 Bo tne locust borer: Hibernation or larval cells.........2..-.--..-...--< 10 6. The locust borer: Reproductive organs of female.................---- il 7. The western pine-destroying barkbeetle (Dendroctonus brevicomis): won wale and femnle: and details.) a ce ee nc ee 18 8. The western pine-destroying barkbeetle: Galleries in the inner bark. - 19 9. The western pine-destroying barkbeetle: Larva............--.------- 20 10. The western pine-destroying barkbeetle: Pupa................------- " 22 11. The western pine-destroying barkbeetle: Pitch tubes on bark of tree. - 25 12. The western pine-destroying barkbeetle: Hibernating or transforma- tion cell, exit burrow, exit holes, pitch tubes...................---- 26 7 Pe eect of the storm of April 24, 1908_:...-...-.....-....--.2..5.44 44 14. The southern pine saywer (Monohammus titillator): Male and female. . . 46 15. The southern pine sawyer: Egg and details.....................----- 47 16. The southern pine sawyer: Larva and details......................-.--. 47 meee SOULHeM pine sawyer: Fiupa..22.2...2-.02. 02. 2.0.26. 2... 2 48 _18. The southern pine sawyer: Egg pit and eggs in position. ............- 51 * 19. The southern pine sawyer: Gallery and details. ....................- 52 20. The southern pine sawyer: Cross section of pupal cell..............-.-. 52 21. The southern pine sawyer: Work of larve in bark.................-.-- 53 22. The southern pine sawyer: Emergence holes of young adults.......... o4 23. Bracon (Melanobracon) webbi: Dorsum of second abdominal segment. . - 4 24. Bracon (Melanobracon) webbi: First four antennal joints. ..........-.-- 54 VII U.S. D. A., B. E. Bul. 58, Part I. F. I. I., June 13, 1906. SOME INSECTS INJURIOUS TO FORESTS. THE LOCUST BORER. ( Cyllene robinix Forst. )4 By A. D. Hopkins, In Charge of Forest Insect Investigations. OBJECT OF PAPER. The object of this paper is to give asummary of the more important published information, supplemented by recently determined new facts relating to the locust borer and methods of controlling it, which will be of service to the investigator in the determination of additional facts, and to the owners of plantations and forests in suggesting methods of preventing losses. ECONOMIC IMPORTANCE OF THE INSECT. The economic importance of the well-known locust borer as affect- ing the growth of the black locust or yellow locust (Robinia pseuda- cacia) is fully realized by everyone who is interested in this valuble forest and shade tree, and the urgent need of additional information on the subject is indicated by the frequent inquiries of correspond- ents and by the recent articles in newspapers, journals, and special publications which have been called forth by the proposed extensive commercial planting of the locust by railroad and other companies and by individuals. INVESTIGATIONS. In connection with the general study of insects injurious to forest trees, the locust borer has received considerable attention by the writer since 1890.2 In March, 1905, a plan of cooperation between the “Order Coleoptera, Family Cerambycide. >From 1890 to 1892 for the West Virginia Experiment Station, and since 1902 for the U.S. Department of Agriculture. l RS TO wate a ee ae a ye ne See a a ge Weegee 2 SOME INSECTS INJURIOUS TO FORESTS. Bureau of Entomology and the Forest Service in the investigation of insect enemies of the black locust was proposed and adopted, by which the subject is receiving special attention from the viewpoint of both the forester and the entomologist, with the primary object of practical results. CHARACTER OF THE INSECT AND ITS WORK. The locust borer isa whitish, elongate, so-called *‘ round-headed” grub or larva (fig. 1), which hatches from an egg (fig. 2) deposited by a black or brown and yellow striped long-horned winged beetle (fig. 3) found on the trees and on the flowers of golden-rod from August to October. The eggs are deposited in the crevices of the bark of living, growing trees from August to October, and the young borers (fig. 2, b, c) hatching there- from mine into the outer portion of the living inner bark (fig. 5), where they pass the winter, and in the spring bore through the bark into the sap- wood and heartwood. Here they transform in July and August to pupe (fig. +4) and in August and Septem- ber to adult beetles, which soon emerge from the trees and de- posit eggs for the next annual generation of Fig. 1.—The locust borer ( Cyllene robinix): a, larva, dorsal view; ), borers and beetles. same,lateralview. Lineat right represents natural length (origi- The inj uly to the nal). The larva in profile should show minute prothoracic feet. of wounds in the bark and sapwood which, if sufficiently severe or repeated year after year, result in either a stunted worthless growth or the death of young and old trees, while the numerous worm holes in the wood reduce its commercial value or render it worthless. The presence of the insect in injurious numbers is indicated (1) by the frequency of the adults on the golden-rod flowers and on the trees, from August to October; (2) by the slight flow of sap and by the brownish borings where the young larve are at work in the bark, during April and May; (3) by the whitish sawdust borings lodged in trees (Pl. I) consists | Bul. 58, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE lI. SCALE OF INCHES. WORK OF THE LocuUST BORER. a, Section of young tree 3 inches in diameter: b, section of young tree 2 inches in diameter, which was broken off near surface of ground; ¢, d, section of branch from badly damaged tree, showing healing wounds in surface of wood; ¢, transverse section of same; /, g, sec- tions of branches one-half inch in diameter or less, showing in each the total length of burrow in which a larva developed and transformed to the adult beetle. (Original.) ——— ‘ THE LOCUST BORER. 3 the rough bark, in the forks of the tree, and on the ground around the base of the trunk, during May, June, and July; (4) by the breaking down of the branches and young trees, and by the sickly appearance of the young twigs and leaves in July and August. This insect appears to be present and more or less injurious in all of that part of the United States which is east of the Great Plains and north of the Gulf States. Published information and reports of forest officials and others indicate that in Oklahoma and Indian Territory and west of the Great Plains the locust is now quite free from injury by the borer; but that these regions will remain exempt is by no means certain. EXTENT OF DAMAGE OR LOSS. So extensive is the damage to natural growth, artificial plantations, and shade trees that in some sections within the natural range of the tree in the Eastern States, but particularly in the Middle West, where both the tree and the insect have been introduced, it is considered unprofitable to grow the tree for shade or timber, and in such sections the natural sprout growth is often considered a pest rather than other- |#T™ wise. The loss resulting from defective timber, stunted growth, and the death of trees is rep- meal a eee tow resented by the difference in value between from hibernation cells. Much the damaged growth or product and the same = “™78°9 (oms!nal. if uninjured and healthy. This, if expressed in dollars, would rep- resent a large sum. POSSIBILITIES OF PREVENTING LOSSES. There are sections, especially in the natural home of the tree, where, as has been frequently observed by the writer and others, the damage is not sufficiently severe to seriously affect the vitality of the trees or the commercial value of the product; and our present knowledge of the insect and of methods of preventing losses from its ravages indi- cates that in properly selected localities, and under proper forestry methods of management, the tree, so far as this insect is concerned, can be grown successfully on an extensive scale, and can be made to yield most satisfactory returns. HISTORICAL REFERENCES. The first reference to this insect, according to Fitch, is a figure and description by Pitiver in his Gozophylacium, published in London in 1702. Drury figured it in 1770, and the following year, 1771, Forster gave it the specific name of rodénzx, under which it is at present rec- PISS RE tar ae ts 2h Se EREEEL TS: 4 SOME INSECTS INJURIOUS TO FORESTS. ognized. It has been referred to many different genera, but 1s now recognized as belonging to the genus Cyllene. Both Drury and Forster received it from the ‘‘ Province of New York,” and referred to it as inhabiting the locust tree (obinza sie e It is there- fore evidently an American species. Some of the principal writers who have contributed important facts on the life history, habits, distribution, and remedies are: Dearborn, 1821; Harris, 1826-1841; Fitch, 1858-1863; Walsh, 1865-1867; Riles 1867; Lintner, 1890; Schwarz, 1890; the writer, 1891-1898; Felt, 1901— 1905; Cotton, 1905; White, 1906, and others. (See list of publica- tions, p. 15.) F1G. 3.—The locust borer ( Cyllene robinix): a, male beetle; b, female beetle. Much enlarged (original). REVIEW OF PUBLISHED DATA. Gen. H. A. S. Dearborn was the first to record the more important facts in the life history and habits of the insect. Indeed, so complete and accurate were his observations that comparatively little has been added by subsequent writers, who have extensively quoted and repeated them. He found the beetles on the trunks of trees from the Ist to the 25th of September, the females depositing their ‘‘snow white” eggs in the crevices of the bark, four to nine in each place. These eggs hatched before cold weather, and ‘‘the young larve just buried them- selves in the tender inner bark,” where they remained until about the 1st of April, when they commenced boring, and soon passed into the solid wood. He stated that it could always be ascertained when and where the borers were at work by the oozing of sap from the wounds THE LOCUST BORER. 5 made by them. By the 20th of July the larve attained their full size, by the 28th some of them changed to pup, and the perfect insects were on the trees September 3. These observations were made on his grounds near Roxbury, Mass., during several years previous to 1821, when they were reported in a letter to John Lowell, and published, together with an account of his unsuccessful experiments with white- wash, mortar, and plaster, in the Massachusetts Agricultural Journal, Volume VI, 1821, pages 270-275. . Col. T. Pickering, in a letter to Mr. Lowell the same year and pub- lished in the same volume, stated that there were trees in New Hamp- shire uninjured by the borer, as well as in some of the Southern States; that he had observed the stems of young trees in Washington, D. C., infested, while in Georgetown(D.C.) he saw large thrifty trees uninjured; and he concluded that natural growth in groves was much less liable to injury than transplanted growth. . Fitch, writing in 1858, stated that numbers of speci- mens were sent to him year after year from Indian Terri- tory. Schwarz (1890) observed that in Fic. 4.—The locust borer (Cyllene robinizx): a, pupa, ventral view; D, and around th e same, dorsal view. Much enlarged (original). District of Columbia the insect lives in large colonies, affecting all trees of small groves, while long hillsides full of locust are not infested. R. S. Kellogg, in his discussion of forest planting in western Kansas, Says: By locating plantation on good ground and giving it first-class care, the trees will reach fence-post size before the borers do much damage. They should then be cut and utilized. The rapid sprout growth will soon make a new crop. made, some epee were appareaila full grown. No pupe or adults of this generation were found up to the time of © the writer’s last observations—on October 10, 1905. Mr. Burke ] found adults, but probably of the first generation, excavating galleries | and Jaret eggs as late as October 26,1904. Thus it appears that the second generation, beginning with the first eggs deposited by adults of the first generation, passes the winter in the larval stage and develops © and emerges by the middle of the following June to the first part of | July. It therefore occupies a period of about 315 to 330 days, includ- ing about 60 days of activity in the fall, 165 days of hibernation, and — 90 to 105 days of activity in the spring and early summer. | s oe THE WESTERN PINE-DESTROYING BARKBEETLE. 25 It is probable that at higher elevations and farther north the majority of the broods would not develop in much less than a year’s time and that at more south- ern and warmer localities in the Pacific Coast region there would be two complete generations and possibly a partial third. HABITS. When first transformed, in May and June, the young bee- tles have very soft, delicate tis- sues. They therefore remain in their pupa cases until their bodies are fully hardened or chitinized. When nearly ready to emerge, the adults bore their way almost to the surface of the bark (fig. 12, a), but pause before emerging, appearing to rest in the burrow. they have just made. They do not, how- ever, hollow out the space im- mediately adjoining the pupa case, as is the habit of another species of this genus. When quite ready to emerge, the bee- tles continue their burrows out through the remaining portion of the bark. The individuals of a brood do not appear to emerge simultaneously, but they come forth at irregular in- tervals until all are out, leaving the bark thickly punctured with small, round, clean-cut holes, as shown in figure 12. After leaving the tree or trees in which they went through their transformations the bee- tles Beeewey tO find treesin 1 re: western s Sceubealéiud in cebeoste which to deposit eggs. They — (Pendroctonus brevicomis): Pitch tubes on bark of may select trees close at hand =" (Onset) or may fly quite a long distance before making a selection. They will also enter the living bark of recently felled trees. Large numbers «f 61830°—Bull. 58—10 9 o 26 SOME INSECTS INJURIOUS TO FORESTS. the beetles usually settle upon a few trees close together and crawl about upon the bark from near the base to about two-thirds of the distance to the tree’s top, seeking suitable places for entrance. Crev- ices in the bark are favorite places with them for this purpose. The female appears to bore the entrance hole in the bark, and may or may not be closely followed by her mate. In some cases where gal- — leries had just been started, females were found alone, that is, one female to a single gallery. Inothers, the female was followed by the — male. As the first incision is made into the living inner bark, the tree begins exuding pitch to cover the wound made by the intruding beetle. This pitch or resin collects at the mouth of the entrance hole in the form usually known as ~ laner Bark, SS Se a pitch tube (figs. 11 and 12, as aa c). Where the attacking force of beetles is small, the efforts of the tree to heal these wounds not infrequent- ly succeed, the flow of pitch © being so great as to overcome © and suffocate the beetles. In such cases the dead beetles | may be found in the pitch masses after the tree has re- covered. Where the attack-_ ing force is large, however, ~ the flow of pitch does not se- riously hinder the beetles. After completing the egg lay- ing, the parent adults remain for some time in the galleries” and excavate irregu!arm Fic. 12.—The western pine-destroying barkbeetle (Den branching burrows toward droctonus brevicomis): a, hibernating or transformation the end farthest from the en- cell; 6, exit burrow; c, pitch tubes and exit holes. : (oneinal) trance, where they remain | until they die. After successfully effecting their entrance into the bark, ths females excavate, through the inner layer of bark, winding, irregular galeries, which run into and cross each other many times (fig. 8). The egg are laid at the sides of the gallery, each in a little niche hollowed out | to receive it and packed in with the borings made in excavating the gallery. Almost immediately after hatching the larva begins feeding upon the cambium surrounding the niche in which it hatched. For a few days it remains in the cambium, then bores out toward the outer bark. As it progresses, it is at the same time growing, and this erowth is indicated by its constantly widening mine or burrow, which | —~ E = a es ar = b < 7 ps ee ba SS. — Se fr a SS a ata a 4 ae: Ss ~SSsS, ———~ WA THE WESTERN PINE-DESTROYING BARKBEETLE. 27 ; is made larger to accommodate the size of the body. Having reached the outer bark, it hollows out an oval space or pupa case, in which to go through its transformations. NATURAL ENEMIES. INSECTS. Larve of the predaceous beetles of the genus Clerus, which are known to prey upon Dendroctonus larve, were quite common in and under the bark of the infested trees, and they doubtless help to some extent in keeping down the numbers of the barkbeetles. BIRDS. Birds contribute their part also in destroying larve and pupe. The work of woodpeckers was found upon most of the trees which had been killed by D. brevicomis, and these birds had evidently destroyed a large percentage ot the insects in some of the trees. METHODS OF COMBATING THE INSECT. FIRST RECOMMENDATIONS. The following information and recommendations relating to this insect and methods of preventing losses from its ravages were conveyed by Doctor Hopkins to Mr. E. M. Hoover, of Boise, Idaho, manager of the Payette Lumber and Manufacturing Company, in a letter dated January 23, 1906, and afterwards published, with Mr. Hoover’s reply, in a local newspaper. } | Our special field agent, Mr. J. L. Webb, has submitted his report on forest insect investi- gations in the vicinity of Centerville and Smiths Ferry, Idaho, during the past summer, and it will interest you no doubt to know that the insect which is primarily to blame for the death of pine trees was located and thoroughly studied by him. He found that the broods of the destructive species pass the winter in the grub state in the bark of trees which died during the late summer and fall and that they do not transform to the v-inged form and emerge untilafter the Ist of May. Therefore the method of combating _ the pest is simply to cut the infested trees any time between the Ist of October and the Ist of May and to remove the bark from the main trunk and burn it. It is necessary to burn the bark in order to kill the broods of this insect, because they occupy the intermediate portion between the inner surface and the outer scale portion; hence the drying of the removed bark will not kill them as it would if they occupied the inner moist portion. _ The infested trees can be located (1) by the yellowish and light reddish brown color of the foliage ; (2) by cutting into the bark as high up on the trunk as a man can reach with an ax to determine whether the middle portion of the bark is infested with the smal! white grubs, which are about three-sixteenths of an inch long. If these are found, it will be conclusive | evidence that the tree has been killed by the beetle and is infested with its broods. It must be remembered that there are hundreds of other kinds of insects which occupy the inner por- tion of the bark and wood of such trees, but none of the smaller ones pass the winter in the @iterbark. * * * Perhaps the most important thing for you to do asa preliminary to any definite action you may take in the matter is to have a number of intelligent cruisers make a survey of your holdings for the purpose of locating the principal sections in which trees have died during the pi j 28 SOME INSECTS INJURIOUS TO FORESTS. past summer and the location of the larger clumps and patches of infested trees within such sections; then, if the locations of the infested areas and clumps are indicated on a map, it will aid materially in planning effectual operations. If you could conduct your logging opera- tions in these sections and utilize the infested trees the desired results would be accomplished without much expense. It is not necessary that all scattering infested trees should be felled and barked, but it is of the greatest importance that all of the larger clumps and patches within the worst infested areas should be thus treated within the period mentioned. If this can not be done this year, the work of locating infested areas should be conducted next sum- mer (1906), in order that the more im portant sections may receive attention next fall and winter. We shall hold ourselves in readiness to give you further information and suggestions on subjects which may not be clear to you, and whenever there is doubt about the insect or its work specimens should be sent to us for authentic identification. In response to this letter, Mr. Hoover wrote: We are most gratified with the information given us and feel that it will be of much value to us in our woods operations. * * * The ferreting out of the insect pest and advising a way to combat it is a work of great value to the country and of especial interest to all persons interested in forests, and we wish to add our word of appreciation of the service of your Bureau. Your letter is clear and explicit, and we will be glad to take advantage of your suggestions in our logging operations and have conveyed the information to other lumber companies operating in this vicinity. Doctor Hopkins has, since then, prepared the following additional recommendations and summary: TRAP TREES. = With our present knowledge of the life history of the western pine- — destroyer and its habits of attacking girdled and felled trees, it is evi- dent that trap trees* may prove effective in keeping the insect under control, especially in localities where only a few trees are being killed — each year or after a large number of the infested trees have been felled and barked in a badly infested locality. The time to girdle and fell trees to catch the first generations would be about the middle of June, the bark to be removed and burned in about 20 to 25 days, or before the broods emerge. Girdled or dead-— ened trees are prepared by the ‘‘girdle to heartwood” method—that is, cutting through the sapwood all around the trunk 3 or 4 feet above the base or as high above the base as convenient to chop; for this pur- pose large, inferior trees should be selected. Felled trees should be lodged or allowed to fall on logs, rocks, ete., so that the prostrate trunks will be as far as possible from the ground. Trees prepared in this manner will usually be attacked by swarms of the beetles, which will excavate galleries in the bark and deposit their egos, iter the eggs have hatched and the larve are about full rou the removal and burning of the bark will effectually destroy the broati and thus contribute greatly to reuters the suinloers of the beetles a Living trees silted or felled at the proper ee to attract the flying beetles to them an away from healthy trees. THE WESTERN PINE-DESTROYING BARKBEETLE. 29 which must occur in large numbers before they can attack and kill a tree. Some of the living trees in the immediate neighborhood of the trap trees may be attacked by beetles attracted to the vicinity by the felled or girdled trees. These should be felled and treated the same as trap trees. If the conditions appear to warrant it, additional trees should be girdled or felled about the first part of August to catch the second brood. These may be barked, to kill the broods, any time between the first part of October and the first part of the feller ing May. SUMMARY. HABITS AND LIFE HISTORY. The western pine-destroying barkbeetle usually attacks and kills the best examples of western yellow pine and sugar pine. If neglected and under certain conditions favorable to the species, it is capable of devastating the pine forests over large areas. The broods of the beetle pass the winter in the outer bark of trees killed by it the previous summer. The adults of the overwintering broods emerge and fly in May, June, and July, the beginning and ending of the period varying with the seasons, latitude, and altitude. The first eggs from the first generation are deposited in June or July, and in some of the warm localities possibly as early as the middle of May. In localities intermediate between the colder and warmer regions the majority of the adults of the first generation evidently develop and emerge in August, but some individuals may remain in the trees until June of the next year. The first eggs of the second generation are evidently deposited in August and September, depending on locality, and it would appear that in intermediate localicies all of the broods of this generation pass the winter (hibernate) in the larval stage in the outer bark. In the warmer localities some of them may develop and emerge in the fall, while in the colder localities there may be but one generation. The first evidence of attack on living trees is the presence of pitch tubes (figs. 11 and 12, c) on the bark or of reddish borings lodged in the crevices and around the base of the tree. During the fall, winter, and following spring, after a successful attack, the infested trees will be indicated by the fading yellowish and reddish leaves. The work of the insect will be indicated by the winding galleries through the inner bark (fig. 8). Trees from which the broods have emerged will be indicated by large numbers of small holes through the outer bark (fig. 12). REMEDIES. _ The principal areas of infestation and the principal patches of Mitested trees should be located in September and October. . 30 SOME INSECTS INJURIOUS TO FORESTS. Beginning with the first part of October, the infested trees should be felled and the bark removed from the main trunk and burned, these — operations to be completed by the first part of the following May. If all of the trees within a given area can not be thus felled and treated, the work should be concentrated on the larger clumps and patches of infested trees. The cost per tree for cutting, barking, and burning the bark will range from about 30 cents to $1, depending on locality and accessi- bility. Summer cutting, except in regular logging operations, is undesir- — able, since the cutting of a few trees in the midst of a large forest may — attract the insects from a long distance, and thus result in extensive © depredations in bodies of timber which it is most desirable to protect. TRAP TREES. In sections where it is known that the beetle is killing some of the timber, trap trees should be provided in June and August. Ordi-— narily, 4 or 5 inferior living trees within each section, on which there is evidence of the work of the beetle, should suffice. Trap trees should not be prepared unless it is reasonably certain that the bark will be removed and burned before the broods of the beetles develop and emerge, otherwise such trees may contribute to the destruction of a larger amount of timber. | STORM-FELLED OR LIGHTNING-STRUCK TREES. Storm-felled and lightning-struck trees are a menace to a healthy forest within the distribution of this insect, since they serve as breed- ing places and centers of infestation. Therefore, whenever practi- cable, such trees should be watched, and if found infested with broods of this beetle, they should be treated as recommended for infested and trap trees. PUBLICATIONS RELATING TO THE WESTERN PINE-DESTROYING © BARKBEETLE. | 1876. LeConte, J. L.—The Rhynchophora of America North of Mexico. Proc. Am. Philos. Soc., Vol. XV, Dec., p. 386. Species described. | 1890. Dietz, W.G.—Notes on the species of Dendroctonus of Boreal America. Trans. Am. Ent. Soc., Vol. XVII, p. 32. Revision notes. 1899. Hopkins, A. D.—Preliminary Report on the Insect Enemies of Forests in the North west. Bul. No. 21,n.s., Div. Ent.,U.S. Dept. Agric., pp. 13-15. First notes on habits. i 1904. Hopkins, A. D.—Catalogue of Exhibits of Insect Enemies of Forests and Forest Products at the Louisiana Purchase Exposition, St. Louis, Mo., 1904. Bul. No. 48, Div. Ent., U.S. Dept. Agric., p. 18. Character of work described. 1905. Currie, R. P.—Catalogue of the Exhibit of Economic Entomology at the Lewis and | Clark Centennial Exposition, Portland, Oregon, 1905. Bul. No. 53, Bur. Ent. U.S. Dept. Agric., pp. 74 et seq. Reprinted from Bul. 48. — es. D: A., B. E: Bul: 58, Part It. F. I. I., March 5, 1907. SOME INSECTS INJURIOUS TO FORESTS. ADDITIONAL DATA ON THE LOCUST BORER. (Cyllene robinix Forst. )4 By A. D. Hopxiys, In Charge of Forest Insect Investigations. This part of Bulletin 58 contains a partial revision of Part I, with additional information based on the results of subsequent investiga- tions by the writer and one of his assistants, Mr. W. F. Fiske. SEASONAL HISTORY. The data under this head refer to the District of Columbia and vicin- ity, latitude 39°, altitude 10 to 90 feet above tide. HIBERNATION. Hibernation begins soon after the larve hatch from eggs deposited at various times from August to October, and the period is passed as minute larvee, scarcely longer than the eggs from which they hatch, in small individual hibernating cells excavated by them just beneath the corky bark and in the outer layers of the living bark on the main trunk of the larger to small trees or small saplings, and larger to small branches. : ACTIVITY OF THE OVERWINTERED LARV®. Activity of the overwintered larve begins in April, or with the begin- ning of the movement of the sap in the bark and just before the leaf buds open. In 1906 activity began April 11; on April 13 the more advanced individuals had entered to the wood, on the 16th were grooy- ing the surface, and on the 25th some of them had entered the wood. By May 11 nearly all of them had entered the sapwood and some of them had extended their burrows into the heartwood and were rapidly ~ @ @ Order Coleoptera, Family Cerambycide. 4 , 31 =) SOME INSECTS INJURIOUS TO FORESTS. increasing in size and yery active, so that by May 20 some of them were more than half grown. They continued actively feeding and growing until after the middle of July, when they began to trans- form to pup and continued transforming during August until all had transformed, probably by the 1st of September. The pupz begin transforming to adults about the 1st of August and continue trans- forming probably into September, although the principal transforma- tion is in August. ACTIVITY OF THE ADULTS. The adults begin to emerge as early as the 7th of August, and con- tinue emerging until the last of September, the greater number com- ing out during the last part of August and the first half of September. Evidently all beetles are out by the first week in October. The females begin to deposit eggs within a few hours after they — emerge. The principal period of oviposition appears to be between the middle of August and middle of September, but oviposition con- tinues until in October. The eggs hatch within eight or ten days — after they are deposited, and the young larve excavate their hiber- nating cells and remain dormant until the following spring. | VARIATION IN SEASONAL HISTORY BETWEEN DIFFERENT LATITUDES AND ALTITUDES. Phenological investigations of plants and insects by the writer® — during the past ten years indicate that the average difference in the dates — of occurrence of the different stages of COyllene robinize at different — latitudes and altitudes in the eastern United States will not be far from four days later for each degree north of latitude 39° and for each 400 feet of altitude above Washington at the same latitude, or four days earlier for each degree south of latitude 39° at the same © altitude. ; Thus, at latitude 43° in central New York, or central Michigan, with altitude the same as at Washington, the dates would be about sixteen days later, and at altitudes of 1,000 feet at latitude 48° they would be about twenty-six days later; at the same altitude as that of Washing- ton at latitude 35° in southern North Carolina and Tennessee they would be about sixteen days earlier or at 1,600 feet elevation about the same. Thus we would have about thirty-two days’ difference between localities at the same altitude in central New York and southern North Carolina. We would also have thirty-two days’ differ- ence between Washington and localities at latitude 39° and altitudes of 3,200 feet in the mountains of Virginia and West Virginia. @ Bull. 50, W. Va. Agric. Exp. Sta., 1898, pp. 17, 18, and Bul. 67, 1900, pp. 241- 248, with map. ADDITIONAL DATA ON THE LOCUST BORER. 33 HABITS OF LARVZ AND ADULTS. When a larva begins activity in the spring it molts and proceeds to excavate an independent food and entrance burrow through the dead area of bark surrounding the hibernating cell or through the living bark immediately surrounding the dead area, until it reaches the cambium. It then excavates an irregular groove or cavity in the outer sapwood, returning frequently to the outer cell or opening to push out the borings and apparently to get relief from the exuding sap. A large per cent of the larve die before any further progress is made, but survivors grow rapidly and soon succeed in overcoming the many obstacles, including natural enemies, resistance of the tree, etc., and enter the sapwood, From this stage on until the larve have attained their full growth they are very active and destructive. Their food consists principally of the nutritious substances of the bark and wood, and probably of the liquids flowing into the burrow, but they do not hesitate to kill and feed upon each other when two or more come in contact within the same burrow. The fact that the entire development often takes place in a burrow scarcely more than twice the length of a matured larva indicates that food must be obtained from some source other than the wood and bark. Throughout its active life the larva frequently returns to the inner and outer bark to enlarge the burrow, and push out its borings, so that the burrow when completed is of a diameter throughout sufficient to allow the passage back and forth of the full-grown larva. When full grown the larva enlarges the.inner end of the burrow, plugs the outer portion with boring chips, and in due time transforms in succession to the pupa and adult. When the adult is fully matured it escapes through the exit prepared by the larva. Immediately after a fernale emerges she is joined by one or more males, and within a few hours, or within twenty-four hours, she pro- ceeds to deposit eggs. She runs about over the bark investigating the crevices, by means of her ovipositor, to locate those most suitable for an egg. Sometimes as many as twenty places are critically examined before one is selected, and it appears that but one egg is deposited in a place by the same female, but other females may find the same place and each deposit an egg, so that sometimes several egos are found in one crevice. Asa rule, however, there is but one. The faculty of the female in locating the most suitable place for an egg by means of the sensitive palpi on the tip of the ovipositor is remarkable. The beetles feed principally on pollen from the flowers of golden-rod, but are very fond of any sweet liquid, such as sugar sirup placed on the trunks of the trees. They are found during the day on the trunks, le 34 SOME INSECTS INJURIOUS TO FORESTS. branches, and foliage of the locust, and during their principal period of activity, from toward the last of August to the middle of Septem- ber, they are especially common on the golden-rod flowers. Mr. Fiske determined that they were also actively copulating and deposit-— ing eggs as late as 10 o’clock at night. The attack of this insect is apparently confined to the black or yellow locust (Robinia pseudacacia). ECONOMIC FEATURES. DESTRUCTIVE CHARACTER OF THE WORK. The destructive character of the work of the locust borer is a matter of great economic importance. This insect attacks the otherwise perfectly healthy trees, and in addition to causing the detrimental — wormhole defects in the wood it often kills the trees or renders an otherwise valuable product worthless except for fuel. It is much more destructive in some localities and sections than in others, and also much more destructive to some trees in the same grove than it is to others. It is more destructive also to young saplings and the branches of medium-sized trees than to the lar ger trees. The death of a tree is caused principally by injuries to the inner bark and cambium, resulting from repeated attacks. Injuries to the wood alone do not result in the death of trees except when all of the wood is practically destroyed or sufficiently injured to cause the tree to fall or be broken down by the wind. The commercial value of the wood product is diminished or destroyed by the wormhole defects, but for certain purposes, as, for instance, fence posts, a limited number of such defects are not detrimental, - except so far as they may contribute to decay. EVIDENCES OF ATTACK. The first evidence of attack is fine brownish boring dust and wet spots on the bark, first observed in April, when the overwintered larvee begin to enter the inner bark. As soon as the larve begin to groove the surface of the wood and enter the sapwood, their presence, in addition to the wet spots, is indicated by yellowish boring dust mixed with liquids and the gum-like exudations. After all of the larve have entered the wood their presence is plainly shown by the quantities of yellowish boring dust lodged in the loose bark on the trunk, in the forks of the tree or branches, and around the base. At this stage, usually about the middle of May, the badly infested trees which will die are plainly indicated by the failure of the leaf buds to open, or by the dwarfed or faded and sickly appearance of the foliage, an toward the last of the month and until the larve have completed thei work in July, by the breaking down of the branches and small trees , nae oan ADDITIONAL DATA ON THE LOCUST BORER. 35 FAVORABLE AND UNFAVORABLE CONDITIONS FOR DESTRUCTIVE WORK. Favorable conditions for the destructive work of the borer appear - to be found in the presence of isolated trees and groves in the open in localities where golden-rod is present or abundant; also, where less resistant varieties of the tree prevail. Unfavorable conditions are found in forest growth or large areas of pure stands, or mixed stands where the locust predominates; also, in plantations and groves where resistant varieties prevail, and where there is no golden-rod or other favorite food for the heetles. It is also found that coarse, thick bark is less favorable than the thinner bark on old and young trees and saplings. NATURAL ENEMIES. INSECTS. Several predaceous insect enemies of the larve have been observed, but so far no true parasites have been discovered. A large elaterid Jarva (/lemirhipus fascicularis Fab.) appears to be the principal enemy of the borer after the latter has entered the wood. It resembles the borer somewhat, but is easily distinguished by the more flattened and shiny body, long prothoracic legs and two curved spines on the last abdominal segment. This predaceous larva is frequently found in the empty mines of the Cyllene larve, therefore ‘it is evidently an enemy of considerable importance. A slender, cylindrical, whitish, footless dipterous larva of an unde- termined species is sometimes found in the mines in the wood, and, according to an observation made by Mr. Pergande, it may attack and kill the borers. Whitish, flattened larvee of the nitidulid genus Ips, with prominent branched hooks on the last abdominal segment, are common in the sap at the entrance of the mines and in the burrows made by the young borers in the inner bark and outer wood. They are supposed to be sap feeders, but the writer found they would attack and devour young Cyllene larvee when confined together in a bottle. Therefore it is pos- sible that they kill a great many of the young borers before these enter the wood, which may account, in part, for the disappearance of such a large number of the young borers while in the bark-boring stage. It was also demonstrated that if several young Cyllene larve of various sizes were placed together in a small vial, the larger ones would kill and eat the smaller ones. It is probable, therefore, that when several larve hatch from a cluster of eggs and but one survives—which is usually the case—the larger or stronger one has killed the weaker ones. 5 36 SOME INSECTS INJURIOUS TO FORKSTS. DISEASE AND SAP FLOW. Dead larve are frequently found in the mines, covered with white ~ flour-like spores, and sometimes these spores are so common that a per- — ceptible cloud rises from the wood when it is split open. Experiments — in placing some of the spores with healthy uninjured larve in bottles, — as well as with those in the normal position in the wood, resulted in ~ the death of the larve and the development of apparently the same — disease, while the duplicate larve kept under the same conditions, but — without contact with the spores, remained normal and _ healthy. ~ Therefore this is a fungus which will kill the borers and one which is evidently of considerable importance. The profuse flow of sap together with a gummy substance in the wounds made in the living bark and cambium is evidently detrimental to the normal progress of the young larve and apparently many of the latter are thus destroyed. METHODS OF CONTROL. It should be remembered that all the holes found in a tree and all © other damage by the borer are not the work of one generation, but usually that of repeated annual attack during the life of the tree; also, that a burrow in the sapwood of a young tree remains the same ~ burrow in the heartwood of the old tree, without change, as long as — the tree exists, except in the healing of the original entrance. The — number of borers and the annual amount of damage is not so great, — therefore, as might appear, and, while each female is capable of depos- iting a hundred eggs, only a small percentage of the larve hatching ~ from them survive the bark-infesting stage or complete their develop- — ment to adults. This suggests that any method of management which will insure the destruction of a large per cent of the surviving larvae — and beetles each year will reduce the damage to a point where there — will be practically no loss. | With our knowledge of the life history and habits of the insect it — is now possible to make definite recommendations and suggestions for its control. Some of those of immediate practical importance are as — follows: TIME TO CUT LOCUST TO DESTROY THE YOUNG LARVZ. The cutting of locust for all purposes, including thinning operations ~ and for private or commercial use, should be done during the period between the 1st of October and the 1st of April, the bark removed — from the crude product, such as posts, poles, and the like, and the tops and thinnings burned. The removal of the bark from all desira- ble portions of the trunks of the trees felled during this period is— important and necessary in order to destroy the larve before they ADDITIONAL DATA ON THE LOCUST BORER. 37 enter the wood. ‘The work in all cases should be completed before the leaf buds begin to swell on the living trees in the spring. DESTRUCTION OF INFESTED TREES AND WOOD. When it is desirable to simply remove and destroy, by burning or otherwise, the badly infested and damaged trees to kill the broods of _larvee, the work should be done in May and June, when all such trees can be easily recognized by the boring dust, fading leaves, broken branches, etc., and must be completed before the beetles begin to emerge. Perhaps the best rule, applicable to all localities, latitudes, _and elevations, is to complete the work by the time the flowers have all fallen from the trees, which will vary between different altitudes ‘and latitudes from about the middle of May to the last of June. Another rule would be to complete the work before the earliest yarieties of golden-rod begin to show evidences of flowering. This, however, would he the latest that the work should be done, because _ the beetles begin to emerge by the time the first golden-rod flowers appear. SPRAYING THE TRUNKS AND BRANCHES TO KILL THE YOUNG LARVZ. Experiments have demonstrated that the hibernating larve may be killed by spraying the trunks and branches with a strong solution of kerosene emulsion. Therefore, when it is practicable or more desir- ‘able to adopt this method for the protection of small plantations, groves, or shade trees, the spraying should be done in the fall or win- ter, not earlier than November 1, and not later than April 1—in other words, during the dormant period of the tree. The following para- graphs, relative to the preparation of kerosene emulsion, are taken from Farmers’ Bulletin No. 127, by C. L. Marlatt: Kerosene emulsion (soap formula )— UD TUS tS ee ee ee, eee Shs eee ee en a ere eee eee gallons.. 2 Whale-oil soap (or 1 quart soft soap)...-........----..2220-+..2-0------ pound... i Oa i ae AE Pg a a ee ae en ee ee gallon... 1 The soap, first finely divided, is dissolved in the water by boiling and immediately added, boiling hot, away from the fire, to the kerosene. The whole mixture is then agitated violently while hot by being pumped back upon itself with a force pump and direct-discharge nozzle throwing a strong stream, preferably one-eighth inch in diameter. After from three to five minutes’ pumping the emulsion should be per- fect, and the mixture will have increased from one-third to one-half in bulk and assumed the consistency of cream. Well made, the emulsion will keep indefinitely, and should be diluted only as wanted for use. For the treatment of large orchards or in municipal work requiring large quanti- ties of the emulsion, it will be advisable to manufacture it with the aid of a steam or gasoline engine, as has been very successfully and economically done in several _ instances, all the work of heating, churning, etc., being accomplished by this means. _ The use of whale-oil soap, especially if the emulsion is to be kept for any length Of time, is strongly recommended, not only because the soap possesses considerable 388 SOME INSECTS INJURIOUS TO FORESTS. insecticide value itself, but because the emulsion made with it is more permanent, and does not lose its creamy consistency, and is always easily diluted, whereas with most of the other common soaps the mixture becomes cheesy after a few days and needs reheating to mix with water. Soft soap answers very well, and 1 quart of it may be taken in lieu of the hard soaps. In limestone regions, or where the water is very hard, some of the soap will com- bine with the lime or magnesia in the water and more or less of the oil will be freed, especially when the emulsion is diluted. Before use, such water should be broken with lye, or rain water employed. * * * For use on locust trees dilute 1 gallon of emulsion with 2 gallons of soft water. Pure kerosene and pure petroleum will effectually kill the insects, but may do some damage to the bark: of the trees. Experiments with carbolic emulsion indicate that this preparation is of no value to kill the young larvee. POISON BAIT. Experiments showed that the beetles would feed readily on poisoned bait, such as sugar, sirup, or molasses with some arsenical mixed in, when this was smeared on the trees. Such baits are fatal to the beetles, but the danger of killing honeybees is so great that their use is not recommended in localities where honeybees are kept. DAMAGE TO CUT WOOD AND DANGER OF INTRODUCING THE INSECT INTO — NEW LOCALITIES. We have determined that after the borers have once entered the wood they may complete their development in the cut and dry branches; they will evidently do so, therefore, in posts or other material manufactured from trees cut between the 1st of May and the middle of September; from this it is plain that locust should not © be cut during this period for any purpose except to destroy the borers, or, if it should be necessary to cut it, the tops should be burned and the logs submerged in ponds or streams for a few days before they are shipped or manufactured. This is very important, both to prevent damage to the manufactured material and the introduction of the insect into the far West and other sections of the country which are at present free from it. Cees eg te er eee 3 f ’ | SELECTION OF LOCATIONS FOR EXTENSIVE PLANTINGS. The fact that there are many sections and localities of greater or less extent within the natural home of the locust and its insect enemies where, from some unknown cause, the tree grows to large size and old age without perceptible injury fr om borers and other insects, sug- gests the importance of selecting such localities for any proposed — extensive operations in the line of artificial planting, or utilization of ADDITIONAL DATA ON THE LOCUST BORER. 39 natural growth. It will be found, however, that no area of consid- erable extent, even in such localities, is entirely free from this and other destructive insect enemies, and that certain precautions and well-planned methods of management with reference to the control of the latter will be necessary. MANAGEMENT OF PLANTATIONS TO PREVENT INJURY. In the first place it is necessary, in order to provide against future losses from the borer, that a thorough survey be made in May and June, not only of the area to be utilized but of the entire neighbor- hood fora radius of a mile or more from its borders, for the purpose _ of locating and destroying scattering trees and groves which are more _ or less seriously infested or damaged by the borer. It would seem that the control of such large areas, by purchase or under a plan of cooperation between the owners of the land or trees, is one of the most important requisites for success in preventing future losses from _ the ravages of this and other insects in small as well as large planta- tions. In fact, itis the writer’s opinion that, with this precaution properly and continuously carried out, locust may be successfully protected from the borer in any locality. | In the subsequent management of plantations and of natural forest ~ and sprout growth it is important each year to locate and destroy the _ worst infested trees for the purpose of killing the borers in the wood, and to conduct the thinning and commercial cutting operations during the period between October of one year and April of the next, in order to destroy the young borers before they enter the wood. Worthless, scrubby, borer-infested trees should be killed outright by _ stripping the bark from 4 or 5 feet of the lower stem during August to prevent sprouts and seed production from them, and at the same time to destroy the eggs and young borers. Trees deadened in this manner will usually be so completely killed that not a single root sprout will appear. Therefore this method is of special value in preventing sprout reproduction from inferior individual trees. SELECTING AND BREEDING BORER-RESISTANT TREES. The fact that some trees are more or less resistant to attack or injury by the borer, while adjacent ones in the same grove are attacked year after year and seriously damaged, suggests breeding races and varie- ties of the species which would be permanently resistant. Breeding experiments have been begun in cooperation with the _ Bureau of Plant Industry and the Forest Service, but it will require several years to get definite results. In the meantime, however, it is important that seed and cuttings for commercial planting should be selected, as far as possible, from trees which show least damage from AQ SOME INSECTS INJURIOUS TO FORESTS. the borer and are otherwise vigorous and healthy. Froma well-estab- lished principle in the heredity of plants and animals, this practice of propagating from the best examples must certainly yield better results — than would follow a disregard of the character of the trees from which | seed or root propagations are made. For reference to literature, and other information not included in this paper, the reader is referred to Part I of this bulletin, pages 1 to 16. U.S. D. A., B. E. Bul. 58, Part IV. F. I. 1., November 10, 1909. SOME INSECTS INJURIOUS TO FORESTS. THE SOUTHERN PINE SAWYER. (Monohammus titillator Fab.) By J. L. Wess, M.8., Agent and Expert. INTRODUCTION. Monohammus titillator, or the southern pine sawyer, has been ' known to systematic entomology for over a century. It is some- what surprising to note, therefore, that scarcely anything is to be found in literature upon the economic importance of this insect, which may truly be said to be one of the most destructive enemies of the crude product of pine forests, especially in the Southern States. Of late years the increasing number of severe storms, so destructive to pine forests in the Southern States, has provided such excellent breeding places for the sawyer in felled trunks and standing stubs that its work is now known to every lumberman in that section of the country as one of the worst injuries to his industry with which he has to contend. The increasing demand by these lumbermen for exact information in regard to the insect rendered necessary a personal investigation of the seasonal history, habits, and facilities for control. To that end the writer spent the months of July and August, 1908, in southern Mississippi, near the town of Baxterville, for the purpose of studying the insect and its habits and conducting a few experiments to determine the best remedy for combating it. Subsequently trips were made to this region in October, 1908, and March, 1909. Investigations were also made, in the latter part of July, 1908, in a district near Kentwood, La., that had been visited by a cyclone, and in a similar district near De Queen, Ark., in October, 1908. The results of these investigations are given in the following pages. The writer desires to acknowledge, in this connection, the courtesy and kindness of Mr. E. McLennan, of Hattiesburg, Miss., general agent for a company controlling timber land in that vicinity, in furnishing trees on the company’s property to be felled for use in seasonal history experiments. 61830°—Bull. 58—10 4 41 42 SOME INSECTS INJURIOUS TO FORESTS. HISTORY. In 1775 Fabricius published a short description of the adult from a specimen in the British Museum, calling it Lamia titillator, and gave its habitat as ‘‘Carolina.”’ He also published short descrip- tions under the same name in 1781 and 1787. Somewhere between 1788 and 1793, the exact date unknown, Linneus, in the Systema Nature, edited by Gmelin, published a short description under the name Lamia titillator Fab. In 1792 Fabricius again published a short description of titillator, and also published a description of Lamia dentator, with ‘‘Carolina” as habitat. The latter name has since been placed in synonymy. Olivier, in 1795, published a short description and figure of the adult under the name Cerambyx titillator Fab. He gives it the common name ‘‘Capricorne chatouil- leux” or the “long-horned tickler,” and the habitat as ‘‘Carolina.”’ At the same time he published a short description and figure of Cerambyx carolinensis (common name, the Carolina longhorn), which has since been made a synonym of titillator, and gave the habitat as South Carolina. Somewhere between 1795 and 1811, the exact date not being known, the same author published short descriptions of Lamia titillator and Lamia carolinensis, giving the habitat of the former as ‘‘Carolina,’”’ and of the latter as South Carolina. In 1805 Beauvois published a short description and figure under the name — Lamia dentator. In 1835 Serville described the genus Monohammus, and placed dentator and carolinensis in it, without mentioning ftitil- — lator. Le Conte, in 1854, published a short description and placed — dentator and carolinensis in synonymy. In this connection he says: © ‘“Olivier’s carolinensis very obviously is the female of his titllator. * * * Jt is common in the Southern States.” | In 1862 Harris, in his Insects Injurious to Vegetation, published a short description, with a figure and a note on the habits of adults, but stated that the kind of tree the ‘‘grub”’ inhabited was unknown to him. In 1873 Le Conte published a description of Monohammus minor, which has since been made a synonym of titillator. At the same time he published a short description of M. titillator. Of the — genus Monohammus, he says: ‘‘The species infests pine trees through- out the whole extent of the United States and contiguous northern regions.”’ In the same year Bowditch, under the name WM. dentator, published short descriptions of the larva, pupa, and adult, and a short note on seasonal history and habits. He found it infesting Pinus matis (echinata) in Massachusetts. In 1885 Horn published a short description under the name WM. titillator and placed the names carolinensis, dentator, and minor in synonymy. He gave the dis- tribution as from Canada to Washington Territory and south to Florida. In 1899 Hopkins published a short note on the occurrence THE SOUTHERN PINE SAWYER. 43 of this species resting upon pitch and scrub pine trees at Tibbs Run, near Dellslow, W. Va. In the same year Chittenden published a a short account of the destructive habits of the species of the genus Monohammus. J. B. Smith, in his Insects of New Jersey, published the same year, mentions this species as occurring throughout the State on pine in June and July. In 1906 Felt, in his Insects Affect- ing Park and Woodland Trees, under the name WM. titillator (common name, tickler), published a very short description, saying further that it was met with in very small numbers [in New York] in 1901 on both white pine and hard pine. DISTRIBUTION. The records of the Bureau of Entomology indicate that this species is to be found over the whole eastern half of the United States, from Maine to Texas. As stated in the historical notes, Doctor Horn gave the distribution as from Canada to Washington Territory, and south to Florida, but I have not been able to verify his state- ment as to the northern and western limits of distribution. HOST PLANTS. So far as known, this species attacks only pine trees, not favoring any one species of pine, but apparently attacking all species of pine trees within its range of distribution. CONDITION OF TREES ATTACKED. Only felled or injured trees are attacked by this species. So far as known, healthy standing trees are never in any danger whatever from this source. INJURY TO PINE FORESTS BY STORMS. In September, 1906, a high wind accompanied by rain, blowing _ steadily for two or three days, uprooted a vast amount of pine tim- ber in the southern part of Mississippi. In May, 1907, near Tuscaloosa, Ala., a storm occurred which felled about 800,000 feet of pine timber. On April 24, 1908, a cyclone of huge proportions passed through Mississippi and Louisiana, tearing down a swath of timber from 1 to 2 miles wide (fig. 13). The cyclone passed through some of the finest pine forests in these States, thus bringing down or breaking off many millions of feet of timber. It is quite probable that the Same storm did damage in Arkansas. At any rate, two storms occurred in Arkansas, one in April and one in May, 1908, both of which were very destructive to pine timber. During the fall and winter of 1908 two or three more storms occurred in the same State _ which doubtless contributed to the destruction of the pine forests. 44 SOME INSECTS INJURIOUS TO FORESTS. INJURY TO STORM-FELLED TIMBER BY THE SOUTHERN PINE © SAWYER. Practically all timber felled by the storm of September, 1906, became infested by the sawyer. When the writer reached Bax- terville, Miss., July 6, 1908, the broods had all matured and emerged from these trees. In this vicinity, where most of his investigations were carried on, from 75 to 90 per cent of the trees felled by the storm of April 24, 1908, were infested by the sawyer. Adults were at that time actively engaged in laying eggs in the uninfested trunks Fig. 13.—The effect of the storm of April 24,1908. (From a photograph taken near Baxterville, Miss.) and stubs. This continued for the balance of the summer, so that it is safe to say that a very small percentage of the pine timber injured by this storm escaped infestation. The damage to each _ log infested is the work of the larve or grubs which mine in and | through the sapwood, and even penetrate the heartwood, making | large unsightly holes which cause the lumber made from this por- tion of the log to be thrown into the very lowest grade, known to | the lumbermen as ‘‘No. 2 common.” = | THE SOUTHERN PINE SAWYER. 45 PECUNIARY LOSS. Approximately 25 per cent of the lumber in each log infested by the sawyer is seriously damaged. The pecuniary loss may therefore be computed as follows: Lumber undamaged by insects was worth, in 1908, $19 a thousand feet b. m. at the mill in southern Mississippi. When infested by the sawyer the 25 per cent damaged was reduced in value to $7.50 a thousand. It is estimated that‘in the storm of September, 1908, 2,000,000,000 feet of timber were blown down. In the 1907 storm, in Alabama, 800,000 feet were blown down, and in the storm of April 24, 1908, which passed through two or three States, 180,000,000 feet were blown down. This gives us 2,180,800,000 feet of timber blown down by these three storms. Practically all of this storm-felled timber was damaged by the sawyer. As stated above, 25 per cent of each log damaged is reduced from $19 a thousand feet to $7.50 a thousand feet; therefore we may consider that 25 per cent of the whole, or 545,200,000 feet b. m. was reduced from $19 a thousand to $7.50 a thousand. At $19 a a thousand this amount of timber would be worth $10,358,800. At $7.50 it would be worth $4,089,000. The difference between these two sums is $6,269,800. Therefore, if this timber had been used, or could have been used before the sapwood decayed, the last figure given would represent the total loss chargeable to the sawyer. CHARACTER OF THE INSECT. Adult.—The adult (fig. 14) is an elongate beetle varying from 16™ to 31.5™" in length and from 5 to 10™" in width. The color is a mottled gray and brown. In the male the horns, or antenna, are very long, often being two or three times the length of the beetle. In the female they are much shorter than in the male, but are still somewhat longer than the body. Kgg.—The egg (fig. 15) is elongate-oval, approximately 4™™ long, by 1.5™™ in diameter at the middle. The color is opaque white. There are two distinct coverings, which correspond to the outer and inner shells of the egg of a fowl. The outer is known as the chorion (fig. 15, a, d), and the inner as the amnion (fig. 15, 6). At one end _isfound a depression or little round hole, which is known as the micro- pyle (fig. 15, ¢). Under a high-power microscope the chorion is seen to be very prettily sculptured on its outer surface (fig. 15, e). _Larva.—The larva (fig. 16) is an elongate, footless, white grub with powerful jaws or mandibles for boring through the wood. The size varies considerably in different individuals and according to age. The largest at maturity have been found to measure slightly over 60™™" in length and 9™™" in breadth at the broadest point (the pro- 46 SOME INSECTS INJURIOUS TO FORESTS. Fia. 14.—The pine sawyer (Monohammus titillator): 3, Male; Q,female. Enlarged about one-third. (Original.) = pata oes. THE SOUTHERN PINE SAWYER. 47 thorax). Larve which develop into the smaller sized adults are, of course, much smaller than this at maturity. The body is divided into 14 well-marked segments. The first is the head. The following three constitute the thorax, the first being the prothorax, the second the mesothorax, and the third the metathorax. The following 9 seg- ments constitute the abdomen, and are desig- nated as the Ist, 2d, 3d, etc., abdominal seg- ments. The last segment is called the anal segment. The head (fig. 16, a) is considerably longer than broad, and is capable of being deeply retracted into the thorax. The pro- - thorax, upon the anterior part of the upper or dorsal surface, is smooth and shining, but the oe eee nore _ posterior part has an opaque leathery appear- >, amnion; c, micropyle; e, ance. This opaque surface is dotted over by pavers Nara small shining spots more or less longitudinally __ inal.) elongate in shape. The mesothorax is smooth upon the upper or dorsal surface, but on the lower or ventral surface is found a double transverse row of fine fleshy granules. On the ex- treme anteriorportion of the side of this segment isfound a transverse, oval, brown spot. Thisis the first spiracle or breathing pore. On the Fic. 16.—The pine sawyer. Larva, slightly enlarged: a, Fore partof head; 6, second abdominal segment; c, abdominal spiracle. a, b, Greatly enlarged. (Original.) metathorax a double transverse row of granules occurs, both on the dorsal and on the ventral surface, but there is nospiracle upon this segment. On the first 7 abdominal segments there are 4 rows of granules on the dorsal surface (fig. 16, 6), and 2 on the ventral. The 48 SOME INSECTS INJURIOUS TO FORESTS. last 2 segments are free from granules. On the anterior half of the side of each abdominal segment except the last, a spiracle (fig. 16, c) similar to that on the mesothorax, except that it is much smaller, is to be found. In mature larve each abdominal segment bears a longi- — tudinal fold on each side, known as the pleural fold. On immature larve the pleural folds on the first 2 abdominal segments are so obscure as to be scarcely noticeable. The anal fold is quite hairy and bears the anal opening. Numerous hairs occur upon each segment of the entire body. Pupa.—The pupa (fig. 17) shows the form in some degree of both the larva and the adult. The number of segments is the same as in the larva; the first abdominal segment, however, is not visible upon the under side of the body. The head is of the same general shape as that of the adult, but is bent forward and under, so that the mouth-parts point directly back toward the posterior end of the body. Several bristles are found upon the anterior part of the head. The antenne are well developed and are coiled on the under side of the elytra, or wing covers, which extend from the mesothorax ina posterior lateral direction, the tips being directly underneath the body and attain- ing the fourth abdominal segment. The elytra thus he between the body and the first two pairs of legs. The third pair of legs is between the body and the elytra. The wings are flattened against the under side of the elytra, each one projecting tron, under whichit lies. The elytra are attached to the mesothorax and the wings to the meta- Fic. 17.—The pine sawyer: thorax. aa een nat- There is a large fleshy tubercle at each side of the prothorax. The legs are folded underneath the body. The first pair is borne by the prothorax, the second by the mesothorax, and the third by the metathorax. The mesothorax bears a spiracle in the same position as that of the larva, and the first 5 abdominal segments bear spiracles; the rest apparently donot. Upon the dorsal surface all segments of the thorax and abdomen bear bristles. The ventral surface of allabdominal segments, except the last, issmooth. The last abdominal segment, which occupies the extreme posterior end of the body, has a peculiar triangular shape. One of the points of the triangle is prolonged upward into a sharp, chitinized spine. The two lower points of the triangle are armed with several chitinized bristles. The anal segment occurs directly beneath the last abdominal segment, and is inclosed on three sides by the latter. A strongly marked sexual difference is to be found between the anal segment of the male and that slightly beyond the outer side margin of the ely- - * THE SOUTHERN PINE SAWYER. 49 of the female. In the male this segment shows merely the anal open- ing. In the female two globular tubercles are borne side by side on this segment. SEASONAL HISTORY. There are four stages in the life of the sawyer, first, the egg (fig. 15); second, the larva (fig. 16); third, the pupa (fig. 17); fourth, the adult (fig. 14). In southern Mississippi the egg-laying period lasts from about the first of March to the middle of October. In some cases eggs may be laid earlier or later than the dates given, but the main activity in egg-laying will be found to be comprised within this period. The young larve hatch from the eggs in about five days after the eggs are deposited.% The length of time from the hatching of the young larva to the time of maturity and change to the pupa appears to vary considerably in different individuals. The comparative periods of time spent in the larval and pupal stages arenot known. However, it is probable that while the larval period may last for several months the pupal period is not longer than two or three weeks. The length of time occupied in passing from the egg to the adult stage varies greatly ‘in different individuals. It appears that normally there is one generation a year, with a partial second generation. Thus, on August 12, 1908, the writer found larve, pupz, and emergence holes in the trunk of a tree which had been felled by storm April 24, 1908. The fact that the tree was felled on this date makes it certain that the eggs of the sawyer were deposited subsequently. This gives us a period of less than four months for the development | from the egg to the emerged adult, in some individuals. Returning _ to the same tree October 6, 1908, more emergence holes were found, but there were still plenty of larve in the trunk. Also, scattering emergence holes were common at this date in other trees felled by the storm of April 24, 1908, which were also abundantly infested with larve. On March 19, 1909, the writer again visited the tree _ just mentioned, and found a good many larve and one pupa still in the log. Thus it is seen what a great variation in the length of time taken for development there may be among different individuals in the same log. The case of the sawyer in the Southern States appears to be somewhat analogous to that of certain species of _ Lepidoptera, a few adults of which emerge in the fall, while the greater number of the pupx go through the winter before changing @ This statement is based upon observations made during the hottest part of the | summer. Possibly eggs laid in the spring or fall might not hatch so quickly, as there _ would be less heat at those periods. 50. SOME INSECTS INJURIOUS TO FORESTS. to the adult. In the case of the sawyer, however, the winter is passed in the larval stage and not the pupal stage. In November, 1908, Mr. R. W. Van Horn found emergence holes of the sawyer in trees felled the previous spring near Virginia Beach, Va., thus showing that the same conditions prevail there. Among the larve which pass the winter in the logs, those which are farthest advanced in development are, of course, the first to go through the changes to the adult, and to emerge in the spring. It is probable that this emergence begins about March 1. At the time the writer was in southern Mississippi, March 18-20, 1909, many adults had already emerged and others were ready to emerge. Fe- males were actively engaged in laying eggs at this time. Just how long it takes for all the overwintered larve, which have not already done so, to go through the changes to the adult stage and emerge is not known, but it is probable that this will be accomplished at least by June 1. ; From the last of July, 1908, to the first of February, 1909, the writer had trap trees felled at stated intervals, for the purpose of getting seasonal history notes. The following tabulation shows the net results of these experiments: Seasonal history records of the pine sawyer from pine trees felled from July, 1908, to February, 1909. Hopk. Date of | Firsteggs U.S. Condition on March 18-19, 1909. No. | felling. noted. 1908. 1908. 5873 | July 29 | Aug. 6] Larve and pupzin wood. A good many adults have emerged. 5874 29 6 | Larvee, pupz, and youngadultsin wood. A good many adults have emerged. 5879 | Aug. 10 13 | Larvee and pupz in wood. No emergence holes noted. 5880 10 i3 Do. 5885 BOW Rae az ee | Larvee and pupe plentiful in wood. No emergence holes noted. 5886 PAD) isc Larve and pup commonin wood. Three adults have emerged. 5893 Sy le cere Larve and pupein wood. Several adults have emerged. 5894 SD ety Se Larvee and pup in wood very scarce. One young adult (quite small). Two adults have emerged. aes || Seo 1b ee eee Larve and pup# in wood. No emergence holes. 5896 iL eee. yikes Larve and pupe rather scarce in wood. A few adults have emerged. A few larvee between bark and wood, scoring the wood. 5897 28 | Oct. 7 | Larve and pupzin wood. One larva found between bark and wood, which © crawled back into its holeinthe wood. Oneadult has emerged. 5898 28 7 | Larvee, pup, and young adults in wood. Several adults have emerged. BOAR Octal) oe gate Larvee, some of which have not entered wood, othersin wood with exit burrow — excavated nearly to surface. No pupz or emergence holes. — 5915 UG |S Serae ee Larve, some between bark and wood, scoring the wood, not having made ~ entrance holesinto wood. Othersin wood with emergence gallery excavated — nearly to surface. No pups or emergence holes noted. SED INO 6) lsoesuessee A few inconspicuous egg pits evidently made last fall. Two half-grown larve, - one of which had commenced to mine into the wood. The other had not commenced to do so. im é 5913 Sete es ae Two or three egg pits, evidently made last fall, but no larve or eggs found. SOOM DCC rSass eee e Many egg pits. Eggs and young larve in some cases, in others the conditions — seem to have become unfit by reason of the excavations of other insects. 5911 Sai ae se aes Many egg pits. Eggs and young larve under bark. f 1909. 1909. v4 Ry dais. 9 7S s ae teceae A few egg pits of Monohammus witheggs. Onesmall larva found. 4 5909 ONGC aa Spe egg pits over thelog. Eggs and larve apparently one or two weeks © old. 5906 | Feb. 6 | Mar. 18 | A few egg pits, both in trunk and stump. Eggs under bark, but none found that have hatched. March 20, female digging egg pit. 5907 6 18 | A few egg pits with eggs under the bark. One larva found apparently just hatching. March 20, six beetles, three males and three females, observed — on this log, the females excavating egg pits, two males fighting and the other male hanging on to a female. ] THE SOUTHERN PINE SAWYER. 51 HABITS. Preparatory to laying the eggs, the female digs with her mandibles quite a conspicuous egg pit in the bark (figs. 18, a, and 21, ¢c). This pit is more or less funnel shaped, though sometimes it is merely : transverse slit, and reaches as far as the outermost layer of soft, sappy bark. The female, while digging the egg pit, is generally accompanied by the male, who clasps the posterior end of her body with his fore- legs, and frequently fertilizes her while she is digging the pit. In one instance where the operation was noted, the female did not dis- continue digging while copulation took plies: Many combats take Fic. 18.—The pine sawyer: a, Egg pit; b, eggs in position in which they were placed by female, the outer bark being removed. About one-half natural size. (Original.) place between males for the possession of a female during oviposition. [he ovipositor is thrust into the egg pit and in between the soft, sappy bark and the first layer of outer hard bark, and the eggs are leposited in a circle around the bottom of the egg pit, the egg (or he end of the egg nearest the pit) being placed from one-eighth to | one-quarter of an inch away from the egg pit (see fig. 18, a. As “Many as nine eggs have been found deposited through a sacle pit ypening. In about five days these eggs hatch, and the small larve issuing therefrom begin feeding upon the soft inner bark, and soon work their yay through it, but do not enter the wood until they have attained onsiderable growth. During this period they make irregular gal- Teries through the inner bark just next to the wood, deriving their entire sustenance from the bark and making no marks or cuttings upon the wood. In from eighteen to thirty-two days after hatching the larve mine into the sapwood (fig. 19). A few days previous to this they are to be found cutting rather broad, irregular paths upon the surface of the sapwood with ied: eatal hice fie: 19, d). This rocess is called ‘‘scoring.’”’ After making the entrance into the wood the larvze come out again to feed upon the inner bark, evidently 52 SOME INSECTS INJURIOUS TO FORESTS. retiring into their holes to rest and for protection from their enemies. The chips cut in excavating the hole in the wood, as well as the excre- ment, are packed between the bark and wood and are not thrown Fic. 19.—The pine sawyer. Gallery: a, Entrance hole in wood; 6, emergence hole; c, pupal cell; — d, surface scored by larva before entering wood. About natural size. (Original.) } out upon the ground, as appears to be the case with some other species. In moving about from the entrance of the hole in the wood to the place where food is obtained, very distinct channels are made through this mass of refuse (fig. 21). This habit appears to continue until the this species differs as follows: Second dorsal abdominal segment without a triangular elevated area but with shallow, almost oblique im- pressions as diagrammatically represented — nS SE in figure 23. . Female: Length, 11™™, exclusive of ovi- — BiG Preco ue Fig. 24.—Bracon yositor, which is 6™™; antennz 69-jointed; lanobracon) webbi: (Melanobracon) ; an ies DOrSUnn Or weed ake webbi: Firstfour Proportions and relation of first four joints dominal segment. antennal joints. approximately asin figure 24; joints 4 to : Greatly enlarged. Greatly enlarged. 55 subequal, becoming wider than long; cOnetal-) (Oneal) joints 55 to 69 becoming longer than wide, the apical joint conical. Petiole of first discoidal cell about as long as second and ~ third joints of antenna combined. Second dorsal abdominal segment perfectly smooth. Type.—No. 12585, U.S. National Museum. Type locality, Baxterville, Miss., March 19, 1909. , ; Hopk. U. S. No. 5896a; reared by Mr. J. L. Webb, of the Bureau © of Entomology. REMEDIES. Fire—During the logging operations upon the storm-felled ~ timber near Baxterville, Miss., in 1908, the felled timber was burned — over with the object of destroying the broods of the sawyer. Sub- ~ sequent examinations of this burned-over area disclosed the fact — that a very small percentage of the larvee had succumbed to the ~ heat. This method is, therefore, not to be recommended. Scoring.—Several experiments were tried to determine the effi-— ciency of “scoring,” or removing a strip of bark along the upper — surface of a log. In some instances salt was sprinkled along the — a By H. L. Viereck, Agent and Expert, Bureau of Entomology. 6 1906, Trans. Am. Ent. Soc., pp. 176-177. Le a | cr THE SOUTHERN PINE SAWYER. scored surface, and in others the strip was covered with brush, these having been recommended locally as remedies. In not a single instance was the scoring, either with or without salt, found to deter the larve in the slightest degree. This method is not recom- mended. Placing logs in water.—Investigation of the method of destroying the larve in infested logs by placing the logs in water was made at Lumberton, Miss., where logs from the storm-felled trees were placed in the mill pond. The water killed all the larve in the log, "both between the bark and wood and in the wood itself. This method is to be recommended wherever practicable. _- Barking the logs.—Barking the logs is effective up to the time the _ larve enter the wood, and for a short time thereafter—perhaps a week. As stated elsewhere, the first part of the life of the larva is spent between the bark and the wood, during which the larva feeds upon the soft inner bark. It is absolutely impossible for the larva to live for the first month of its existence without this soft inner _ bark to feed upon. ‘Therefore, if the bark be removed from the log - during this period all larve between the bark and wood will be destroyed. As stated elsewhere, the larve continue to feed upon the inner bark for several days at least, after first entering the wood. _ The writer determined by experiment that the barking of the log during the first few days after the larve have entered the wood was effective in destroying the larve, by cutting off their food supply. _ At this period the larve have not gone deeply into the wood, so _ that there would still be a saving if the barking were done at this timé. Where this method is practiced as a remedy, it should be done within forty days after the eggs are laid. If trees are felled between March 1 and October 15, egg laying will probably com- ~ mence at once after the trees are down. An important point to be taken into consideration in this con- _ nection is whether or not logs and trees barked to destroy the sawyer’ can be taken to the mill before the sapwood decays from lying on the ground. As the greater part of the injury by the sawyer is con- fined to the sapwood, there will obviously be little or no saving in parking logs which can not be used before the sapwood is destroy ed by decay. _ The writer realizes, also, that in some cases barking may not be profitable for other reasons. The local conditions in regard to labor are often far from satisfactory. And it may be quite impos- sible to assemble enough laborers to bark all the trees felled by a _ heavy storm in time to save them from injury by the sawyer. It is also true that in cyclone-felled timber the trunks are often so_ piled up and entangled that it would be necessary to saw them into logs and separate them before they could be barked. However, taking all these points into consideration, the writer feels that in the 56 | SOME INSECTS INJURIOUS TO FORESTS. majority of instances a great saving can be accomplished if the matter is promptly taken in hand, and as many trunks as possible barked before or shortly after the larve enter the wood. In each case the holder of storm-felled timber must decide for himself. If the cost of barking the felled trunks is low enough to give a fair profit on the material saved from injury, it is a simple proposition — of business economy. In any case the matter should be given careful consideration before all effort to prevent loss from the ray-— ages of the sawyer is abandoned. SUMMARY OF REMEDIES. If possible saw all storm-felled trunks into logs and place the logs vn water before the larve enter the wood, or within forty days after the eggs are laid. If it is impossible to place the logs in water, they should be barked within forty days after the first egg pits are observed vn the bark. BIBLIOGRAPHY. 1775. Fapricius, J. C. Lamia titillator. Systema entomologiz, p. 172, No. 11. 1781. Fasricrus, J. C. Lamia titillator Fab. Species insectorum, Tom. I, p. 219, No. 17. 1787. Fasricius, J. C. Lamia titillator Fab. Mantissa insectorum, Tom. I, p. 187, No. 21. 1788-93. Linnzus, C. Lamia titillator Fab. Systema nature, edit. Gmel., p. 1831, No. 162. 1792. Fasricius,J.C. Lamia titillator Fab. Entomologia systematica, emend., Tom. I, V, pars 2, p. 279, No. 47. Lamia dentator, ibid., p. 278, No. 43. 1795. Giger A. G. Cerambyx titillator. Bngewiotaci ou histoire naturelle des — insectes, Vol. IV, p. 85, genus 67, pl. 15, fig. 109. 1795. OurvieR, A.G. Cerambyx carolinensis. Ibid., pp. 85-86, pl. 12, fig. 88. 1795-1811. Ontvier, A. G. Lamia titillator Fab. Encyclopédie méthodique, Vol., VII, p. 463. - 1795-1811. ‘Ouiv ER, A.G. Lamia carolinensis. Ibid. 1805. Patisot DE Beauvoris. Lamia titillator. Insectes recueillis en Afrique et en Amerique, pp. 244-245, pl. 36, fig. 5 : 4 1854. Le Conte, J. L. Monohammus nicdlatar Fab. Journ. Acad. Nat. Sci. Phila. 2d series, Vol. II. 1862. Harris, T. W. Menohammus titillator Fab. Insects injurious to vegetation, pp. 105-106. (Possibly M. scutellatus.) 1873. Le Conts, J. L. Monohammus minor. New species of North American — Coleoptera, p. 231. 1873. Le Conts, J. L. Monohammus titillator Fab. Thid. 1873. Bowpircu, F. C. Monohammus dentator. Am. Nat., Vol. VII, pp. 498-499. 1885. Horn, Geo. H. Monohammus titillator Fab. Trans. Amer. Ent. Soc., Vol. XII, pp. 190-193. 1899. Hopkins, A. D. Monohammus titillator. Bul. 56, W. Va. Agr. Exp. Sta., p. 439. | si | 1899. CHITTENDEN, F. H. Monohammus titillator. Bul. 22, Div. Forestry, U. Sa Dept. Agr., pp. 57-58. 1899. SuirH, J.B. Monohammus titillator Fab. Insects of New Jersey, p. 293. 1906. Feit, E. P. Monohammus titillator Fab. N. Y. State Museum, Memoir 8, | vol. 2, pp. 339, 365. “ : sd wD. S. D. A., B. E. Bul. 58, Part V. F. I. I., December 4, 1909. SOME INSECTS INJURIOUS TO FORESTS. _ INSECT DEPREDATIONS IN NORTH AMERICAN FORESTS AND PRACTICAL METHODS OF PREVENTION AND _ CONTROL. | By A. D. Horxkins, Ph. D., In Charge of Forest Insect Investigations. INTRODUCTION. It is the purpose of this part of the bulletin to give a summary of acts, conclusions, and estimates relating to the forest-insect problem ; as applied to North American conditions and to call attention to its —— ~ importance in the future management of private, state, and nati forests. The matter is presented in as brief and concise a form as possible, in order that the information may be readily available to the general reader, as well as to the forester and student, and references are made to publications in which more detailed accounts may be found. The statements and conclusions relating to the insects and their work and to methods for their control are based almost entirely on ‘Investigations and observations by the writer and by assistants in the Bureau of Entomology working under his direction, carried on in all of the principal forest areas of the United States. The his- torical data have been gathered from the publications listed on pages 96-97. The estimates of the amount and value of standing tim- ber killed by insects and of the forest products destroyed and reduced in value through insect injuries to the crude and seasoned products are based on our published results of investigations (pp. 97-100), on unpublished notes, on technical and practical knowledge of the sub- ject, and on the published forest statistics relating to the amount and value of timber, fire losses, etc. (pp. 100-101). INSECT DEPREDATIONS IN NORTH AMERICAN FORESTS. CHARACTER AND EXTENT OF DEPREDATIONS. The records of notable depredations by insects on the timber sup- ply of Europe during the past four hundred years, on that of the 61830°—Bull. 58—10-——5 ay 4 a 58 SOME INSECTS INJURIOUS TO FORESTS. United States during the past century, and especially those that have come under the observation of the writer and assistants engaged — in forest insect investigations during the past eighteen years, furnish conclusive evidence that this class of enemies has been, and is now, an important factor in the destruction and waste of forest resources. — INSECTS CAUSE THE DEATH OF TREES. It has been conclusively demonstrated that certain species of insects are the direct or primary cause of the death of forest trees of all ages, and that from time to time they multiply to such an alarming: extent that their depredations assume the character of a destructive invasion, which results in the death of a large percentage of the best timber over thousands of square miles. There are many species of barkbeetles which prefer to attack matured and healthy trees, and there are many examples of whole forests of century-old trees having perished from the girdling effect of the mines of the beetles, which are extended in all directions through the inner living bark on the main trunks of the trees. Indeed, we find among these bark-boring beetles the most destructive insect enemies of North American forests. Some notable examples of the depredations of these barkbeetles are given below. The southern pine beetle——In 1890-1892 a destructive invasion of the southern pine beetle (Dendroctonus frontalis Zimm.) extended from the western border of West Virginia through Maryland and Virginia into the District of Columbia, northward into southern Pennsylvania, and southward into North Carolina. In this area, ageregating over 75,000 square miles, a very large percentage of the mature and small trees of the various species of pine and spruce was killed by this beetle. In many places in West Virginia and Virginia nearly all the pine trees of all sizes on thousands of acres were killed, while shade and ornamental trees within the same area suffered the same as those in the forest. Since 1902 this barkbeetle has been more or less active in the Southern States from Virginia to Texas, and in some localities and during certain years it has killed a large amount of timber. Records of extensive destruction of timber in the Southern States are found dating back to the early — part of the nineteenth century (Wilson, 1831). This species may be — considered one of the most dangerous insect enemies of southeastern — conifers and, therefore, a constant menace to the pine forests of the Southern States. (Hopkins, 18996, 19036, 19090.) The eastern spruce beette.—During the period between 1818 and 1 1900 there were several outbreaks of the eastern spruce beetle (Den- — droctonus piceaperda Hopk.) in the spruce forests of New York, | New England, and southeastern Canada (Peck, 1876, 1878; Hough, — 1882; Packard, 1890; Pinchot, 1899, p. 74; Hopkins, 1901a, 1909). ee ae ee ed eg ee ee INSECT DEPREDATIONS IN NORTH AMERICAN FORESTS. 59 This species caused the death of a very large percentage of the ma- ture spruce over an area of thousands of square miles. In the aggre- _ gate many billions of feet of the best timber were destroyed. The larger areas of this dead timber furnished fuel for devastating for- est fires, with the result that in most cases there was a total loss. The Engelmann spruce beetle-——Another barkbeetle (Dendrocto- nus engelmanni Hopk.), similar in habits to piceaperda, has from time to time during the past fifty years caused widespread devasta- _ tions in the Rocky Mountains region to forests of Engelmann spruce, in some sections killing from 75 to 90 per cent of the timber of mer- _chantable size. (Hopkins, 1908a, p. 161; 1909, pp. 126-132.) The Black Hills beetle—One of the most striking examples of the destructive powers of an insect enemy of forest trees is found in the Black Hills National Forest of South Dakota, where during the past _ ten years a large percentage of the merchantable timber of the entire forest has been killed by the Black Hills beetle (Deadroctonus pon- _ derose Hopk.). It is estimated that more than a billion feet of _ timber have been destroyed in this forest as the direct result of the work of this beetle. This destructive enemy of the western pine is distributed throughout the forests of the middle and southern Rocky Mountains region, where, within recent years, it has been found that in areas of greater or less extent from 10 to 80 per cent of the trees have been killed by it. (Hopkins, 1902a, 1903, 19056, 1908a, and 1909, pp. 90-101.) The mountain pine beetle and the western pine beetle—The sugar pine, silver pine, western yellow pine, and lodgepole pine of the region north of Colorado and Utah, westward to the Cascades, and southward through the Sierra Nevadas are attacked by the mountain pine beetle (Dendroctonus monticole Hopk.) and the western pine beetle (Dendroctonus brevicomis Lec.), and, as a direct consequence, billions of feet of the timber have died. In one locality in north- ~ eastern Oregon it is estimated that 90 to 95 per cent of the timber in a dense stand of lodgepole pine covering an area of 100,000 acres has been killed within the past three years by the mountain pine beetle. Throughout the sugar-pine districts of Oregon and California, as the result of attacks by this same destructive barkbeetle, a considerable percentage of the largest and best trees is dead. (Webb, 1906; Hop- kins, 1908a, 1909, pp. 80-90.) The Douglas fir beetle—The Douglas fir throughout the region of the Rocky Mountains from southern New Mexico to British Co- ~ lumbia has suffered severely from the ravages of the Douglas fir beetle (Dendroctonus pseudotsuge Hopk.), with the result that a large percentage of dead timber is found, much of which will be a total loss. (Hopkins, 19096, pp. 106-114.) Three other species of beetles, having destructive habits similar 0 those above mentioned, depredate on the pines of New Mexico mee . a 60 : SOME INSECTS INJURIOUS TO FORESTS. and Arizona, and still another has-contributed greatly to the de- struction of the larch throughout the northeastern United States and southeastern Canada. (Hopkins, 19090, pp. 49, 53, and 77.) The hickory barkbeetle-—Within the past ten years the hickory oarkbeetle (Scolytus quadrispinosus Say) has caused the destruction of an enormous amount of hickory timber throughout the northern tier of States from Wisconsin to Vermont and southward through the eastern Atlantic States and into the Southern States as far as central Georgia. (Hopkins, 1904, pp. 314-317.) The larch worm.—There are also many examples of widespread ~ depredations chargeable to insects which defoliate the trees, thus contributing to their death. Notable among these are the. depreda-— tions by the larch worm (Nematus ertchsonizi Hartig), which, during ~ several extensive outbreaks since 1880, has killed from 50 to 100 per cent of the mature larch over vast areas in the northeastern United States and southeastern Canada. It is evident that the amount of merchantable-sized timber that has died as the result of defoliation by this insect will aggregate many billions of feet. (Packard, 1890, pp. 879-890; Pinchot, 1899; Hopkins, 1908q.) Insz¢€r INJURIES TO THE Woop or LIVING TREES. It has been determined that insects of a certain class attack the wood and bark of living timber and that, while they do not con- tribute materially to the death of the trees or give much external evidence of their presence, they produce wounds in the bark and wormhole and pinhole defects in the wood which result in a depre- ciation in commercial value amounting to from 5 to 50 per cent. These defects in the wood are not detected until after the trees have been felled and the logs transported to the mill and converted into lumber. Thus to the actual damage to the lumber is added the. expense of logging and manufacture of the defective, low-grade ma- terial, much of which must be discarded as worthless culls. (Hop- kins, 1894a, 18940, 19040, 1905a, 19060.) Ae is oak timber worm aa of the most Ager age of the class of depredators just mentioned is the oak timber worm (L'upsalis minuta Dru.). It enters the wood of the trunks of living trees through wounds in the bark and at the base of broken or dead branches and extends its “ pinhole” burrows in all directions through the solid heartwood. The losses occasioned by this insect in the hardwood forests of the eastern United States are enormous and usually affect the wood of: the finest examples of old trees. (Hopkins, 1894a, 19040.) The chestnut timber worm.—The chestnut throughout its range is damaged in a like manner by the chestnut timber worm (Lymeaylon sericeum Harr,). Practically every tree of merchantable size is PR RMN Mh his OBEN Ns Wei Se ee INSECT DEPREDATIONS IN NORTH AMERICAN FORESTS. 61 more or less affected, and a large percentage is so seriously damaged that the product is reduced to that of the lowest grade. It is esti- mated that the reduction in value of the average lumber product at any given time is not far from 30 per cent, thus involving extensive waste and an increased drain on the forest to supply the require- ments for clear lumber. This insect also attacks the oaks, and especially the red oak, the older trees of which are often as seri- ously damaged as are the chestnut. (Hopkins, 1894a, 19040.) Carpenter worms.—The oaks, especially the white oak and the red oak, are seriously damaged by carpenter worms of the genus Prion- oxystus. The holes made by these insects through the heartwood of the best part of the trunks are sometimes 1.5 inches in diameter one way by 0.75 inch the other, thus causing serious damage to the wood. These, with other large wood-boring beetle larvze, sometimes infest the top part of the trunk and the larger branches of oak trees, where their continued work results first in the dead and so-called “ stag- horn” top and subsequently in broken, decayed, and worthless trunks. (Hopkins, 1894a, 19040.) Ambrosia beetles —One of the commonest defects in white oak, rock oak, beech, whitewood or yellow poplar, elm, etc., is that known to the lumber trade as “ grease spots,” “ patch worm,” and “ black holes.” This defect is caused by one of the timber beetles or ambrosia beetles, Corthylus columbianus Hopk., which makes successive attacks in the living healthy sapwood from the time the trees are 20 or 30 years old until they reach the maximum-age. Thus the black-hole and stained-wood defect is scattered all through the wood of the best part of the trunks of the trees. The average reduction in value of otherwise best-grade lumber amounts, in many localities, to from 25 to 75 per cent. The defect is commonly found in oak and elm furniture and in interior hardwood finish in dwellings and other buildings. (Hopkins, 18939, 18940, 19040.) The locust borer.—The locust, as is well known, suffers to such an extent from the ravages of the locust borer (Cyllene robiniw Forst.) that in many localities the trees are rendered worthless for commercial purposes or they are reduced in value below the point of profitable erowth as a forest tree, otherwise this would be one of the most profit- able trees in the natural forest or artificial plantation and would con- tribute greatly to an increased timber supply. (THopkins, 1906/, 1907a, 1907c.) Turpentine beetles and turpentine borers—While the softwood trees, or conifers, suffer far less than the hardwoods from the class of enemies which cause defects in the living timber there are a few notable examples of serious damage. There is a common trouble affecting the various species of pine throughout the country known as basal wounds or basal] fire wounds. It has been found that a large 62 SOME INSECTS INJURIOUS TO. FORESTS. percentage of this injury to the pine in the States north and west of the Gulf States and in the Middle and South Atlantic States is caused by the red turpentine beetle (Dendroctonus valens Lec.) and in the Southern States by the black turpentine beetle (Dendroctonus terebrans Oliv.). These beetles attack the healthy living bark at and toward the base of the trunks of medium to large trees and kill areas varying in size from 1 to 10 square feet. These dead areas are sub- sequently burned off by surface fires and are then generally referred to as fire-wounds. The further damage to the exposed wood by successive fires, decay, and insects often results in a total loss of the best portion of the tree, or a reduction in value of the lower section of the trunk of from 10 to 50 per cent. (Hopkins, 1904a, 1909.) These and similar wounds in the bark of trees, including those caused by lightning and by the uncovering and exposure of the wood in tur- pentining, offer favorable conditions for the attack of the turpentine borer (Buprestis apricans Hbst.), the work of which, together with that of two or three others with similar habits, is very extensive, and causes losses amounting to from 10 to 50 per cent of the value of the wood of the best part of the trees thus affected. (Hopkins 19042.) The white pine weevil_—The abnormal development of white pine trees as the result of succesive attacks on the terminals of the sap- lings and young trees by the white pine weevil (Pissodes strobi Peck) is an element of loss of considerable importance, especially in mixed stands and in open pure stands of this timber. The value of such trees is reduced from 20 to 50 per cent below those of normal develop- ment, and there is an additional loss from the effect of their spread- ing branches or crowns in the suppression or crowding out of trees which would otherwise occupy the space thus usurped. (Hopkins, 1906c, 1907d.) There are many other examples of insects which damage the wood and bark of living trees, but those mentioned should be sufficient to demonstrate the importance of insects in this relation. INSECT INJURIES TO THE Woop or DYING AND DEAD TREES. Timber dying from insect attack and other causes, including fire, disease, storms, etc., is attacked by certain wood-boring insects which extend their burrows through the sound sapwood and _ heartwood, and thus contribute to the rapid deterioration and decay of a com- modity which otherwise would be available commercially during periods of from one to twenty years or more after the death of the trees, depending on the species of trees and on the character of the product desired. This loss often amounts to from 25 to 100 per cent during the period in which the dead timber would otherwise be almost as valuable asif living. (Hopkins, 1894a, 1901d, 1904a, 1905a; Webb, 1909. ) pews Ti PM a eta) ge INSECT DEPREDATIONS IN NORTH AMERICAN FORESTS. 63 CONIFEROUS TREES. Sawyers.—One of the most striking examples of the destruction or deterioration of the wood of dying and dead timber, familiar to all lumbermen, is the injury to fire-killed and storm-felled pine, fir, spruce, etc., caused by boring larve known as “ sawyers.” These borers hatch from eggs deposited by the adult beetles in the bark of the dying trees, and after feeding on the inner bark for a time they enter the solid wood and extend their large burrows deep into the heartwood. Fire-killed white pine is especially liable to this injury, and is often so seriously damaged within three or four months dur- ing the warm season as to reduce the value of the timber 30 to 50 per cent. The shortleaf, loblolly, and longleaf pines of the Southern States are damaged to a somewhat less extent, but instances are known in which more than one billion feet of storm-felled timber within limited areas were reduced in value 25 to 35 per cent within three months after the storm. (Webb, 1909.) The fire-killed and insect-killed sugar pine, silver pine, and yellow pine of the western for- ests are also damaged in a similar manner and the value of the prod- uct greatly reduced within a few months after the trees die. The aggregate losses from this secondary source in the coniferous forests of the entire country contribute largely to the annual waste of mil- lions of dollars’ worth of forest products which otherwise might be utilized. (Hopkins, 1905a, p. 385; Webb, 1909.) Ambrosia beetles —W ood-boring insects of another class, known as timber beetles or ambrosia beetles, cause pinhole defects, principally in the sapwood, although some of them extend their burrows into the heartwood. These insects make their attack in the early stage of the declining or dying of the tree, or before the sapwood has materially changed from the normal healthy condition, and often in such num- bers as to perforate every square inch of wood. Thus the wood is not only rendered defective on account of the presence of pinholes, but the holes give entrance to a wood-staining fungus which causes a rapid discoloration and produces still further deterioration of the _ product. The sapwood of trees dying from the attack of other insects or from fire, storm, or other causes is often reduced in value 50 per cent or more, and in some cases the value of the heartwood is reduced in a like manner from 5 to 10 per cent. (Hopkins, 18940, 1895c, 1898, 1904a, 1905a.) Pinhole borers in cypress —An example of the destructive work _ of insects which attack dying and dead trees is found in the cypress - in the Gulf States, where these trees are deadened by the lumbermen and left standing several months, or until the timber is sufficiently dry to be floated. Upon investigation it was found that trees dead- 64 SOME INSECTS INJURIOUS TO FORESTS. ened at certain seasons of the year were attacked by the. ambrosia beetles or pinhole borers, and that in some cases millions of feet of © timber had been reduced 10 to 25 per cent or more in value. (Hop- kins, 19070.) HARDWOOD TREES. Roundheaded borers, timber worms, and ambrosia beetles —The principal damage to dying and dead hardwood trees is caused by cer- tain roundheaded wood-borers (Cerambycide) with habits similar to the sawyer, by the timber worms mentioned as damaging living timber, and by ambrosia beetles having habits similar to those that attack the sapwood and heartwood of conifers. All of the hardwoods suffer more or less, but the greatest damage is done to the wood of hickory, ash, oak, and chestnut, which are often reduced in value 10 to 25 per cent or more within the period in which it would otherwise remain sound and available for commercial purposes. (Hopkins, 1894a, 19044, 1905a.) INSECT INJURIES TO FOREST PRODUCTS. Damage is caused by various species of insects which are attracted by the varying conditions prevailing at different stages during the process of utilizing the forest resources, from the time the trees are felled until the logs are converted into the crude and finished product and until the latter reaches the final consumer, or even after it is placed in the finished article or structure. As a result, additional drains are made on the timber to meet the demand for the higher grades of lumber and for other supplies to replace those injured or destroyed. From the writer’s personal investigations of this subject. — in different sections of the country it is evident that the damage to forest products of various kinds from this cause is far more extensive than is generally recognized. This loss differs from that resulting from insect damage to standing timber in that it represents more directly a loss of money invested in material and labor. (Hopkins, 1894a, 1903c, 1904a, 1905<.) CRUDE PRODUCTS. Roundheaded borers, timber worms, and ambrosia beetles—Round timber with the bark on, such as poles, posts, mine props, sawlogs, — etc., 1s subject to serious damage by the same class of insects as those — mentioned under injury to the wood of dying and dead trees. The — damage is especially severe when material is handled in such a man- ~ ner as to offer favorable conditions for attack (Hopkins, 1905a), as when the logs are left in the woods on skidways or in mill yards for — a month or more after they have been cut from the living trees. Under such conditions there is often a reduction in value of from 5 to ~ 30 per cent or more, due to wormhole and pinhole defects caused by INSECT DEPREDATIONS IN NORTH AMERICAN FORESTS. 65- roundheaded and flatheaded wood-borers and timber beetles. Fre- quently the insects continue the work in the unseasoned and even dry lumber cut from logs which had been previously infested. They also continue to work in mine props after they have been placed in the mine, and in logs and other material used for the construction of cabins, rustic houses, etc., and in round timbers generally. The products from saplings, such as hickory hoop-poles and like _ material, are often seriously injured or rendered worthless by round- headed and flatheaded borers and wood-boring beetles, sometimes resulting in a loss of from 50 to 100 per cent of the merchantable _ product. (Hopkins, 1905za.) _ Stave and shingle bolts left in moist, shady places in the woods or in close piles during the summer months are often attacked by ambrosia beetles and timber beetles. The value of the product is _ often reduced, as a consequence, from 10 to 50 per cent or more. ; _ (Hopkins, 1894a, 1905a.) Handle and wagon stock in the rough is especially liable to injury j by ambrosia beetles and roundheaded borers. Hickory and ash bolts 7 from which the bark is not removed are almost certain to be greatly ; damaged if the logs and bolts cut from living trees during the winter and spring are held over for a few weeks afier the middle of March or first of April. (Hopkins, 1905z.) Pulpwood, and cordwood for fuel and other purposes, cut during :. winter and spring and left in the woods for a few weeks or months or in close piles after the beginning of the warm weather, are sometimes riddled with wormholes or converted into sawdust borings, causing a loss of from 10 to 100 per cent. One example reported from near Munising, Mich., represents a loss of $5,000 from injury to ‘spruce and fir pulpwood cut in the winter and kept in piles over ‘summer. | MANUFACTURED UNSEASONED PRODUCTS. Ambrosia beetles and other wood borers.—Freshly sawed hard- wood placed in close piles during warm, damp weather during the period from June to September is often seriously injured by am- brosia beetles. Heavy 2-inch to 3-inch stuff is also liable to attack by the same insects, even in loose piles. An example of this was found in some thousands of feet of mahogany lumber of the highest grade, which had been sawed from imported round logs and _ piled with lumber sticks between the tiers of plank. Native species of ambrosia beetles, principally Pterocyclon mali Fitch, had entered the wood to such an extent as to have reduced the value 50 per cent or more within a few weeks. Oak, poplar, gum, and similar woods often suffer severely from this class of injury, causing losses vary- ing from 5 to 50 per cent. (Hopkins, 1905c.) 66 SOME INSECTS INJURIOUS TO FORESTS. Lumber and square timbers of both soft and hard woods with the bark left on the edges are frequently damaged by flatheaded and — roundheaded wood borers, which hatch from eggs deposited in the — bark before or after the lumber is sawed. There are examples of losses from this character of injury amounting to from 20 to 50 per cent or more. | Telegraph and telephone poles, posts, mine props, etc., are fre- quently injured before they are set in the ground, especially if the bark remains on them during a few weeks after the middle of March. SEASONED PRODUCTS IN YARDS AND STOREHOUSES. Powder-post beetles—Hardwood lumber of all kinds, rough handles, wagon stock, etc., made partially or entirely of sapwood, — are often reduced in value from 10 to 90 per cent by a class of insects known as powder-post beetles. The sapwood of hickory, ash, and oak is most lable to attack. The reported losses from this source during the past five or six years indicate that there has been an average reduction in values of from 5 to 10 per cent or more. (Hop- kins, 1908c, 1905a.) | Old hemlock and oak tanbark is often so badly damaged by vari- ous insects which infest dead and dry bark that in some tanyards as much as 50 to 75 per cent of the bark that is over three years old is destroyed. In one tannery in West Virginia it is estimated that more than $30,000 worth of hemlock bark was thus destroyed. (Hop- kins, 1905a. ) FINISHED PRODUCTS. The greatest loss of finished hardwood products, such as handle, wagon, carriage, and machinery stock, is caused by powder-post beetles. This is especially true of hickory and ash handles and like products in the large and small storehouses of the country, including the vast amount of material held in storage for the army and navy. When material of this kind is once attacked it is usually worthless for the purposes indicated, and therefore must be replaced with new — material. In some cases losses have amounted to from 10 to 50 per — cent, and it 1s estimated that the average losses have been as much as_ 10 per cent on nearly all sapwood material that has been in storage more than one year. (Hopkins, 1903¢, 1905a.) UTILIZED PRODUCTS. Powder-post beetles, white ants, and other wood-boring insects.—_ The finished woodwork in implements, machinery, wagons, furniture, and the inside finish in private and public buildings are often seri- ously damaged by powder-post beetles, thus requiring increased de- mands for new material. (Hopkins, 1903c, 1905.) __, Construction timbers and other woodwork in new and old build- ings are often so seriously damaged by powder-post beetles, white ants, and other wood-boring insects that the affected material has to be removed and replaced by new, or the entire structure torn down and rebuilt. (Hopkins, 1905a.) Construction timbers in bridges and like structures, railroad ties, telephone and telegraph poles, mine props, fence posts, ete., are sometimes seriously injured by wood-boring larvae, termites, black ants, carpenter bees, and powder-post beetles, and sometimes reduced in efficiency from 10 to 100 per cent. INSECTS IN THEIR RELATION TO THE REDUCTION OF FUTURE SUPPLIES OF TIMBER. Insects not only reduce future supplies by killing the mature trees and destroying the wood of timber that is inaccessible for utilization, but through injuries inflicted upon trees during the flowering, fruiting, germinating, seedling, and sapling periods of early growth they prevent normal reproduction and development. (Hopkins, 1904a, 1906c.) INTERRELATIONS OF FOREST INSECTS AND FOREST FIRES. Investigations conducted by the writer and assistants in all sec- tions of the country during the past ten years indicate to them quite conclusively that the average percentage of loss of merchant- able timber in the forests of the entire country to be charged to insects during a five or ten year period is infinitely greater than most people realize. (Hopkins, 1906a, pp. 4-5, 19084, p. 345, 19090, pp. 5, 24; Forbes, 1909, pp. 51-52.) Losses from forest insects —The writer estimates (p. 70) that for _a ten-year period the average amount of timber in the forests of the entire country killed and reduced in value by insects would represent an average loss of $62,500,000 annually.* _ It has been estimated (Hopkins, 1905, p. 5; 1908, p. 162) that the Black Hills beetle killed approximately 1,000,000.000 feet b. m. of timber during a period of ten years, which at $2.50 per thousand would amount to an average of $250,000 annually. This is merely | ~- yn one example of very destructive depredations by a single species of barkbeetle in a single national forest.’ (See also p. 70.) _ Prof. Lawrence Bruner, state entomologist of Nebraska, at a meet- ing of the American Association of Economic Entomologists, held at _ *Losses from forest fires—lIt has been estimated that ** on the average, since 1870, forest fires have yearly cost $50,000,000 in timber.” (Cleveland, T., jr., 1909, p. 3.) ‘It has been estimated that the losses of timber from forest fires on all of the National Forests of the United States from 1905 to 1905, inclusive, average only $165,062 annually. (Cleveland, T., jr., 1908, p. 541.) INSECT DEPREDATIONS IN NORTH AMERICAN FORESTS. 67 a 68 SOME INSECTS INJURIOUS ©O FORESTS. Baltimore, Md.. in December, 1908, spoke as follows: “I can agree with Doctor Hopkins that the insects are far more important in destroying our forests than fires.” (Bruner, 1909, p. 53.) Insect-killed timber as fuel for fires——It has often happened that after insects have killed the timber over extensive areas the standing — and fallen dead trees furnished fuel for great forest fires which have not only destroyed or charred the dead timber but killed the living — timber and reproduetion and swept on into adjacent areas of healthy | timber. Indeed, abundant evidence has been found during recent {n- | vestigations to indicate that some of the vast denuded areas in the ~ Rocky Mountains and other sections of the country are primarily due ~ to widespread devastation by insects, and that subsequent fires de- — stroyed the timber and prevented reproduction. (Hopkins, 1906a.) — It is also evident that a considerable percentage of dead timber, — and especially that found in coniferous forest regions, which has gen- | erally been believed to have been fire-killed is a result of primary at- — tack by insects. This has been demonstrated in many cases by the pitch-marked galleries of the destructive barkbeetles on the surface of the wood of the old dead trees which had escaped subsequent fires. ; Fire-killed timber injured by insects.—It is true that a vast amount — of timber has been killed outright or has died as the direct result of forest fires, but in almost every case observed insects have contributed — to a greater or less extent to the death of recently fire-injured trees — which might otherwise have recovered, and especially to the rapid — deterioration of the wood of a large percentage of the injured and killed trees. It is evident that in some cases fire-scorched and fire-— killed timber has contributed to the multiplication of one or more of © the insect enemies destructive to living timber, and thus the injury started by the fire may have resulted in a destructive outbreak of beetles. However, it is evident that this has happened only when the destructive beetle was already present in abnormal numbers in the forest surrounding the fire-swept area. Therefore, it is believed that injuries by fire are not as a rule an important factor in contrib-— uting to subsequent depredations by barkbeetles. Such fires, how- ever, contribute to the multiplication of the insects which depredate | on the bark and wood of dying and dead trees, so that in forested areas where fires are frequent the damage to the wood of such trees’ is more severe, and fewer injured trees recover on account of the abundance of secondary barkbeetle enemies which do not, as a rule, attack and kill ving timber. Destruction of insects by fire.—There is another important feature in the relation of insects and fire, in which the fire contributes to the destruction of the principal barkbeetle enemies of the living timber. This happens when the fire burns the timber while it is infested, thus effectually destroying the broods of the insects. It is perfectly plain that the dying and dead foliage of the beetle-infested trees and the INSECT DEPREDATIONS IN NORTH AMERICAN FORESTS. 69 ~ dead bark on the trunks would contribute to the spreading of crown fires and thus the bark on the entire infested trunks would be suffi- ciently scorched to kill the insects. Therefore, complete fire control may easily contribute to more extended depredations by insects on the living timber, thus increasing, rather than diminishing, the need for insect control. However, the setting of fires or permitting them to burn for the purpose of combating insects should never be under- taken or permitted. Durability of insect-killed timber—Some of the matured larch trees which evidently died as a result of defoliation by the larch - worm between 1881 and 1885, and which had escaped subsequent _depredations by fire and wood-boring insects, were found by the writer in 1908 to be standing and sound enough to be utilized for railroad ties and many other purposes. Under similar conditions the heartwood of red spruce and white pine in the East, of Engelmann spruce in the Rocky Mountains, and of Douglas fir in the Northwest coast region have been found by the writer to be sound enough for _ profitable utilization for pulp wood, lumber, fuel, and other pur- poses from twenty to thirty years after it had been killed by insects or fire. Thus it is shown that timber killed by insects and fire would _ be available for utilization for many years were it not for injuries _ through the secondary attacks of wood-boring insects and the de- struction of insect-killed timber by forest fires. INTERRELATION OF FOREST INSECTS AND FOREST FUNGI. Decay following mjury by imsects—lIt is well known that the _ burrows in the bark and wood of living and dead trees and in the crude and finished products often contribute to the entrance of ‘ bark and wood decaying fungi. Deterioration and decay are thus ; far more rapid than would otherwise be possible. It is also known be that trees injured and dying from primary attack by parasitic fungi are attractive to certain insects which breed in the bark and wood _ of sickly and dying trees, and that certain other complicated troubles affecting forest trees are the result of an intimate interrelation and interdependence of insects and fungi. There can be no doubt, how- ever, that certain species and groups of both insects and fungi are independently capable of attacking and killing perfectly vigorous and healthy trees. SUMMARY AND ESTIMATES RELATING TO CHARACTER AND EXTENT OF | INSECT DAMAGE. The killing of trees by insects; the damage by them to the wood F of living, dying, and dead timber; the destruction of insect-killed _ timber by subsequent forest fires; the damage to fire-killed timber _by insects; and the damage from decay resulting from insect injuries to the wood, have all been more or less continuous for centuries and are still going on in the forest and woodland areas of this country. 70 SOME INSECTS INJURIOUS TO FORESTS. While these depredations are not always evident or important in all forests or localities, yet almost every year, somewhere in the forests of the country, there are widespread depredations. In every forest and woodland there is an ever present but incon- spicuous army of insects which require the bark, wood, foliage, and seeds of the various tree species for their breeding places or food. Thus, the accumulated but inconspicuous injuries wrought during the period required for the growth of a tree to commercial size go far toward reducing the average annual increment below the point of profitable investments. The accumulated damage to crude, finished, and utilized products reduces the profits of the manufacturer, increases the price of the higher grades to the consumer, and results in an increased drain on the natural resources. In any attempt to estimate in dodlars or feet, board measure, the extent of losses or waste of timber supplies caused by insects there are many conflicting factors which contribute to the difficulty of ar- riving at accurate conclusions. The published information concern- ing the amount in board feet of standing timber in the country is admittedly only an estimate, as are also the published data relating to average stumpage value. The published statistics relating to the amount and value of forest products are of course more accurate, but until more complete data can be furnished by the forest experts on the various complicated phases of forest statistics, any figures given by the forest entomologist relating to the value of timber and com- mercial products destroyed or reduced in value by insects must be considered on the same basis as the other estimates, and as the best that can be presented on available evidence. Standing timber killed and damaged by insects—When we con- sider the amount of standing merchantable timber killed by insects and the amount of standing timber, living, dying, and dead, which has been reduced in quantity and value through their agency during a ten-year period, we would estimate that such timber represents an equivalent of more than 10 per cent of the quantity and stumpage value of the total stand of merchantable timber in the United States at any given time.“ A certain percentage of such timber is a total @The estimate of the area and stand of the present forests of the United States, as given in Circular 166 of the Forest Service, page 6, is two trillion five hundred billion feet (2.500,000,000,000) board measure. The average stumpage value has been given as $2.50 per one thousand feet b. m., making a total value of the standing merchantable timber of $6,250,000,000. Ten per cent of this amount would be $625,000,000, as the amount to be charged to in-_ sects for a 10-year period. or an average of $62,500,000 annually. AS an ex- ample, it has been estimated that over 1,000,000,000 feet b. m. of timber was killed by the Black Hills beetle in the Black Hills National Forest within a period of ten years. This, at $2.50 per one thousand feet stumpage, would be an average of $250,000 annually in a single forest of 1,294,440 acres. ~~» «INSECT DEPREDATIONS IN NORTH AMERICAN FORESTS. 5 ie loss because of the impossibility of utilization; but in some cases a greater or less percentage can be, and in some cases is, utilized within the period in which it is of sufficient value to yield a profitable return ‘on the cost of logging and manufacture, although its value is greatly reduced. Reduction in the Nation’s wealth—When we consider the forest esources both in merchantable timber and young growth as an im- portant asset of the Nation’s wealth: as representing a given value to the people for direct utilization; as a cover to the soil for protec- tion of the land from erosion; as protection of headwater streams and of game; and as contributing to the esthetic value of health and pleasure resorts, it would be difficult indeed to estimate the amount or percentage of loss of timber or the reduction in the land values, in each case, chargeable to insects. It is plain, however, that in the aggregate it is considerably greater than when estimated on stumpage values alone. Reduction in cash revenue-——When we consider the problem from the standpoint of direct utilization we can estimate the annual loss on a basis of mill values; but here again we meet with complications, ince much of the damaged material is left standing or is discarded in the woods or at the mill without measurement. Therefore we are left to judge from our observations and knowledge of. the general ronditions as regards dead and damaged timber found in the forests of the country, and the information from lumbermen in different sec- fons, as to the percentage of loss from defective timber. On this asis we can estimate that the amount of insect-killed and damaged amber left in the woods, plus the reduction in value of that utilized, to be charged to insects is not far from an equivalent of 10 per cent of the value of the annual output of forest products of all kinds, in the rough. The total value of the forest products of the United States in 1907 is given as $1,280,000,000; the losses from insect depre- lations would therefore represent an annual loss in a cash value of more than $100,000,000. (Hopkins, 1895c, 1904<.) Reduction in value of finished and commercial products —When re consider the aggregate loss to the manufacturers of the finished yroducts, to the trade, and to the consumer from insect injuries to he wood, it is evident that it amounts to many millions of dollars in iddition to the estimated loss of crude products, or at least 3 per ent of the mill value. METHODS OF PREVENTION AND CONTROL. The results of extensive investigations and of practical applications f the knowledge gained during recent years have demonstrated that ome of the most destructive insect enemies of American forests and f the manufactured and utilized products can be controlled, and te SOME INSECTS INJURIOUS TO FORESTS. 3 serious damage prevented, with little or no ultimate cost over that involved in forest management and business methods. (Hopkins, 1904, 1905a, 1908a, 19090.) | There are, of course, certain insects and certain injuries which, — under present conditions and available information, can not be con- trolled or prevented, but it is very evident that if the information now available through the publications of the Department of Agri-— culture and through direct correspondence with its experts is properly — utilized in the future it would result in the prevention of at least 30 — per cent of the estimated annual waste of forest resources that has been caused by insects within recent years, and thus contribute greatly to the conservation of forest resources. . GENERAL PRINCIPLES OF CONTROL. The ordinary spraying and similar methods employed in dealing © with fruit and shade tree insects are, of course, not available for — practical application in the case of forest trees. But there are other — and less expensive methods of accomplishing the desired results. é In all efforts to control an outbreak or prevent excessive loss from_ forest insects it should be remembered that as a rule it is useless to ~ attempt the complete extermination of a given insect enemy of a_ forest tree or forest product. Experience has demonstrated that it~ is only necessary to reduce and weaken its forces 75 per cent or more. It can not then continue an aggressive attack, but must occupy a defensive position against its own enemies until conditions resulting from avoidable negligence and mismanagement by the owners of the — forests and manufacturers of forest products favor its again becom-_ ing destructive. Forest insects can thus be easily kept under control by good management. ? The desired control or prevention of loss can often be brought about by the adoption or adjustment of those requisite details in forest management and in lumbering and manufacturing operations, stor- ing, transportation, and utilization of the products which at the least expenditure will cause the necessary reduction of the injurious ~ insects and establish unfavorable conditions for their future multipli- ~ cation or continuance of destructive work. It is, however, of the utmost importance that any adjustment or modification in management or business methods should be based on ~ expert technical knowledge or advice relating to the species, habits, | life history, and natural enemies of the insects involved and the es-— sential features of the methods for their control. This should be — supplemented by expert knowledge or advice on the principles of © technical and applied forestry in the proper management, care, and utilization of the forest and its resources, and still further supple-— mented by practical knowledge and experience relating to local con- ca INSECT DEPREDATIONS IN NORTH AMERICAN FORESTS. 73 ditions and facilities favorable and unfavorable for sticcess in prac- tical applications according to the recommended method or policy of control. As has been shown, the mature or merchantable timber is the most usceptible to injury or death from the ravages of insects. There- fore, considered from the standpoint of insect control and the pre- vention of one of the greatest items of loss, it is important that such atured timber should be utilized before it begins to deteriorate, or before it reaches the stage of unprofitable growth. For the greatest success in dealing with forest insects, it must be recognized that there are certain features in the habits and seasonal history of each species which differ to a greater or less extent from those of all other species, even of the same genus; that there are cer- ain features in the characteristics of the various species of trees which differ from those of all other species; and that as a rule it is the technical knowledge of these peculiar features or characteristics of ‘the trees and their enemies which furnishes the clew to successful methods of control. _ There are also many peculiar features in the prevailing conditions in different localities, some of them favorable, others unfavorable, for the practical application according to a given method, so that while certain general advice may apply in a broad sense and be available for utilization by the practical man, whether owner, manager, or forester, without further advice, it is often necessary to diagnose a ‘given case before specific expert advice can be given as to the exact cause and the most effective method or policy to be adopted, just as a physician must diagnose a case of illness or injury before prescribing the required treatment for his patient. | Therefore, in a consideration of the problem as to how far the waste of forest resources caused by insects can be prevented and how far the damaged timber can be utilized, we will attempt to give only general statements based on the results of our observations relating to ‘some of the principal kinds of loss discussed in the first part of this paper, namely, by insects which (1) kill the trees, (2) cause injuries to the wood of living timber, (3) reduce future supplies, and (4) ‘cause injuries to the manufactured products. In addition, we will consider the utilization of natural enemies of injurious insects, the ‘utilization of damaged timber, and the present conditions and opportunities for success in the general control of forest insects. ———_ CONTROL OF BARKBEETLES WHICH KILL TREES. The barkbeetles which kill trees attack the bark on the trunk and destroy the life of the tree by extending their burrows or galleries in 5 directions through the inner living bark. The broods of young grubs or larve develop within the inner bark, on which they feed. 61830°—Bull. 58—10——6 "A SOME INSECTS INJURIOUS TO FORESTS. Those of some species develop to the adult stage within the inner bark and are exposed when the bark is removed, while those of other species transform to the adults in the outer corky bark and the larve are not exposed when the bark is removed. Some species have twe or more generations in a season or annually, while others have but one, and in a few species it requires two years for a single generation to develop. (Hopkins, 19090.) The barkbeetles of the genus Dendroctonus represent the most destructive enemies of the principal coniferous tree species of Ameri- can forests, and at the same time are among the easiest of control. The general requisites for success are embodied in the following rules: (a) Give prompt attention to the first evidence of a destructive outbreak, as indicated by an abnormal percentage of yellow or red topped dying trees, and especially when such trees occur in groups of ten or more or cover large areas; (0) secure authentic determination of the particular species of insect responsible for: the trouble; and (c) take prompt action toward its control according to specific expert advice, published or otherwise, on the best method for the destruction of the necessary 75 per cent or more of the insects in the infested trees, Some of the methods to be adopted to meet the requirements of various local conditions are as follows (1) Utilize the infested timber and burn the slabs during the period in which the broods of the destructive beetles are in the imma- ture stages or before the developed broods emerge from the bark; o1 (2) Fell the infested trees and remove the bark from the main trunk and burn the bark if necessary;¢ or » (3) Remove the infested bark from the standing timber and burn the bark when necessary; or (4) Immerse- the unbarked logs in ponds, lakes, or streams, wher the bark will remain soaked ihre enough to kill the insects; or (5) Remove the unbarked logs or products to a locality where there are no trees liable to attack within a radius of 20 miles or more MAINTAINING CONTROL OF BARKBEETLES. Future trouble of a serious nature from barkbeetles which kill trees ean be prevented within a given forest or area of greater or less extent / if an insect-control policy is adopted in connection with, or independ- ent of, a fire-control policy by which groups of dying trees will receive similar prompt attention as that required for the prevention — or control of forest fires. » | In state and national forests——In all forest reserves in which there is an organized force of rangers and fire wardens or patrols each “Tf the broods develop to adults in the outer bark, it must be burned; if they develop in the inner bark and are exposed when the bark is removed, burning 18° not necessary. AS a rule the burning of the tops to destroy the insects is not necessary. . 3 INSECT DEPREDATIONS IN NORTH AMERICAN FORESTS. 75 % .. officer should be furnished with instructions for the location of beetle- infested trees, and with equipment and directions for taking the necessary action whenever the conditions demand or warrant it. In private forests.—Private forests should receive the same atten- tion as public forests, but this is often far more difficult on account of intervening forests, where the owners either can not or will not give the matter the required attention. While it may be advisable to have some laws to govern the treatment of timber infested with a dangerous pest, when the owner refuses to take any action such a law should apply only to the more extreme cases or as a last resort on authoritative advice. It is probable that in most cases legislation will not be necessary, and more ultimate good will result without than with strict laws, especially when it can be made clear to the owner that his personal interests demand that he take the proper action and that, when necessary, his neighbors will render assistance, as is done in the case of a forest fire. Inaccessible areas-——There are yet large inaccessible areas in the East and West where it is not practicable or possible at present to con- trol the depredations by these beetles and which must therefore be left to the same natural adjustment that has been going on in all for- ests from their beginning. While under such natural control much of the older matured timber will be lost it will usually be replaced by young growth, either of the same species of trees or of a different species, so that under normal conditions the forest will be perpetu- ated; but under exceptional conditions and combinations of detri- mental influences, such as secondary insect enemies, fire, drought, ete., extensive areas may be completely denuded, never to be reforested under natural conditions. Therefore it will evidently not be very long before it will pay to adopt insect-control policies even in the areas that are inaccessible for profitable lumbering. EXAMPLES OF SUCCESSFUL CONTROL OF BARKBEETLES. We have a sufficient number of examples of successful control of depredations by the destructive barkbeetles to demonstrate the prac- ticability of the advice based on the results of recent entomological investigations. Control of the eastern spruce beetle—The control of an alarming outbreak of the eastern spruce beetle (Dendroctonus piceaperda Hopk.) in northeastern Maine in 1900 and 1901 was effected by the concentration of regular logging operations into the areas of infested timber and placing the logs in lakes and streams and driving them to the mills on the Androscoggin River. Thus, with little or no addi- tional expense, there was a saving to one firm, according to its esti- mates, of more than $100,000. ———— 76 SOME INSECTS INJURIOUS TO FORESTS. Control of the Black Hills beetle—An extensive outbreak of the Black Hills beetle (Dendroctonus ponderose Hopk.) in the vicinity of Colorado Springs, Colo., in 1905-6, which was threatening the living pine timber of the entire section, was brought under control through the efforts of the private owners of forests and those of for-_ est officials in the adjoining National Forests. It was accomplished by cutting and barking about 1,000 beetle-infested and beetle-killed — pine trees. The cost of the operations was largely, if not entirely, covered by the utilized felled timber, although there was consider- able unnecessary expense involved through the felling and barking of trees from which the beetles had emerged and from the unnec- essary burning of the bark and tops. The successful control of another serious outbreak of the Black Hills beetle, in 1906, on an extensive private estate in southern Colo- rado, was effected through the efforts of the owners, who had some 500 infested trees felled and barked within the necessary period to destroy the broods. A large percentage, but not all, of the infested timber was thus treated. These operations were so successful that not a single infested and dying tree could be found when the area was imspected in 1908. In this, as in the other case, considerable unnec- essary expense was involved in the burning of the bark and tops, — but the value of utilizable timber was evidently more than enough to pay all expenses. It is evident that in this case a destructive inva- sion was prevented. The most striking example of success relates to a large estate near Idaho Springs, Colo., and in the adjoining Pike National Forest. In May, 1907, it was found that some 63,000 feet of standing timber | on the estate was infested by the Black Hills beetle, and the owner was advised by the Bureau of Entomology that unless the ravages were checked at once the beetle would Inill the timber not only on _— this estate but that on the adjoining estates and National Forest, and that therefore radical action should be taken according to the rec- ommendations and detailed instructions given relating to a necessary — control policy. No action was taken, however, before the first of the following July, and therefore not in time to prevent the broods of beetles from swarming from the infested trees and extending their ravages. In December, 1907, another examination of the timber was made, and it was found that instead of 65,000 feet of timber in the old infestation there was nearly four times as much timber involved in the new, or over 250,000 feet. The owner was again notified of the serious character of the outbreak, and further | suggestion made that if the logs from the infested trees were con- verted into lumber and the slabs burned before May, 1908, it would result in the protection of the remaining living timber. Immediate steps were then taken by the owners to carry out the original ecommendations. An expert in locating infested timber, working under instructions from this Bureau, gave instructions to the mana- ger of the estate in locating and marking the infested trees and in the essential features in the methods of utilization to destroy the necessary number of beetles; he also marked infested timber on an adjoining estate and on the National Forest. Five months later, in ‘May, 1908, this expert reported that the larger clumps of infested trees on the estate had been converted into lumber and the slabs burned, and that the marked trees on the adjoining estate and National Forest had been cut and barked. In November, 1908, another inspec- tion of the forest on the estate and surrounding area was made by the expert, and on December 1 he reported as follows: Nothing could be more satisfactory than the results obtained by the cutting of the infested timber on the estate. Your recommendations and instructions submitted to the owner, and carefully followed by the manager of the estate, have clearly demonstrated that insect infestation can be controlled, and at no expense to the owner of the timber involved; in fact a very satisfactory price was realized, resulting in a net profit, I understand, of over $5 per thousand feet, board measure, on the 240,000 feet cut. This, of course, does not inelude the profit of the milling operations, but for the logs sold at the mill, after de- ducting the expenses of cutting and logging. The sawmill was owned and oper- ated by an Idaho Springs firm, and the manufactured article sold in that town. _ I spent six days on the estate, November 18 to 23. After a very thorough ex- amination of the timber, I found only three infested trees, isolated individuals, and over a mile from where the large clumps of infested trees were cut. With the exception of those three trees, there is no new infestation on the estate. I also examined the adjoining lands, but no new infestation was observed. The infested trees which I marked in December, 1907, had been cut and barked. On the Pike National Forest, contiguous to the first mentioned estate, where you will remember I marked some clumps of infested trees, no new infestation was found, not one tree. This most gratifying result demonstrated two important things: One, that an extensive outbreak by the most destructive barkbeetle enemy of the pine timber of the central Rocky Mountain forests, in- volving in this case more than 1,000 infested trees, can be controlled without expense, and even at a profit, whenever the conditions are favorable for the utilization of the infested timber; the other, that the essential details of the recommendations and expert advice, based ‘on the results of scientific research, can be successfully applied by a manager of a private forest or by the rangers of national and state forests. It also indicates quite conclusively that the widespread dep- redations in the Black Hills National Forest could have been prevented with very little expense to the Government if the matter had received prompt attention in 1901, when the first investigations were made and essentially the same recommendations submitted. But, through the lack of public appreciation of the importance of the problem at e time, and the lack of sufficient authority and funds later, the out- break was allowed to extend beyond practical control, and in conse- INSECT DEPREDATIONS IN NORTH AMERICAN FORESTS. (a ¥ oe ee 78 SOME INSECTS INJURIOUS TO FORESTS. quence a large percentage of the timber of the entire National Forest has been killed. There were, then, no forcible examples of the prac- tical value of such recommendations based on scientific research, and no other argument was effective in arousing public interest in the threatening character of the outbreak or confidence in scientific ad- vice or methods of control. Now we have several examples demon- strating the practicability of forest-insect control in America which should lead to confidence in the results of scientific research as a basis for success in practical application. Control of the hickory barkbeetle—The complete coe of the hickory barkbeetle (Scolytus quadrispinosus Say), which threat- ened the total destruction of the hickory trees on Belle Isle Park, at Detroit, Mich., in 1903, was effected by felling and removing the infested trees and converting them into merchantable products, all without cost to the park commission. (Hopkins, 19040.) CONTROL OF INSECTS WHICH CAUSE DEFECTS IN LIVING TIMBER. The class of insects which causes defects in the wood of living timber can be controlled to a greater or less extent, depending upon local conditions, and a large percentage of the losses prevented through the adoption of certain requisite details in forest manage- ment. Of these the following are especially important: (1) The utilization of all of the defective and infested timber that will pay expenses for manufacture into merchantable products, such as lumber, cordwood, ete. (2) The burning of infested timber and waste material not avail- able for use, including dead standing and fallen timber, to remove the breeding places of insects like the oak timber worm and the chestnut timber worm, which go from the dead to the living timber. (3) The prevention of wounds of any kind in the bark of /living trees. (4) The prevention of future losses by the practice of improved forestry methods which will eliminate favorable conditions for injury and contribute to a perpetual supply of vigorous, healthy timber to be utilized before it passes the stage of profitable increment. PREVENTION OF INJURY TO DYING AND DEAD TREES. A large percentage of the injury to the wood of insect, fire, and hghtning killed trees and those killed or dying from injuries by storms, disease, etc., can be prevented as follows: (1) By the prompt utilization of such timber within a few weeks or months after it is dead or found to be past recovery. (2) By removing the bark from the merchantable portions of the trunks within a few weeks after the trees are dead (the work to be done either before or after the trees are felled). INSECT DEPREDATIONS IN NORTH AMERICAN FORESTS. 79 (3) By felling the trees and placing the unbarked logs in water. _ (4) By the adoption of a system of forest management which will provide for the prompt utilization of all trees which die from any ~—eause. PREVENTION OF LOSS FROM INSECT INJURIES TO NATURAL AND ARTIFICIAL REPRODUCTION. The successful control of the insects which destroy or prevent the normal development of natural reproduction is a far more difficult problem than that presented by other classes of insect injuries, but in this as in the others a great deal can be accomplished toward pre- venting the reduction of future supplies. Much can be accomplished in nurseries and small plantations by the adoption of the ordinary methods of controlling farm and or- chard insects, but in the natural forests reliance must be placed largely on systems of forest management which will bring about unfavorable conditions for the work of the more important enemies. _ (Hopkins, 1906c.) ia i > r . | _ UTILIZATION OF IMMUNE AND RESISTANT VARIETIES AND RACES OF TREES. | 2 Certain .individuals representing varietal or racial forms of trees of a given species are sometimes found to be either immune or de- -cidedly more resistant to the insects which are destructive or seri- ously injurious to the life or wood of other individuals or varieties of the same species. This fact suggests the importance of recogniz- ‘ing the well-known principle of improvement by selection. Thus, selecting seed or cuttings from such immune and resistant trees for artificial propagation, or taking great pains to leave such trees in commercial or selection cuttings for natural reproduction, will un- oubtedly be an important step toward providing against damage nd loss in the future. (Hopkins, 19060, 1907a, 1907c, 1907d.) PREVENTION OF INSECT INJURIES TO FOREST PRODUCTS. — The problem of artificial control and prevention of insect injuries 0 forest products offers less difficulties perhaps than that relating o many other branches of the general subject of forest-insect con- trol. In most cases the principle of prevention is the only one to be considered, since the damage is done soon after the insects enter the ‘wood, and therefore it can not be repaired by destroying the enemy. i | , CRUDE Propucts. ; b The proper degree of moisture found in the bark and wood of 80 SOME INSECTS INJURIOUS TO FORESTS. during a few weeks or months in the spring and summer, or during the period when the particular species of injurious insects are flying, are some of the conditions most favorable to attack. The period of danger varies with the kind of timber and the time of the year it is i felled. Those felled in late fall and winter will generally rental attractive to ambrosia beetles and adults of round and flat headed — borers during March, April, and May. Those felled during the pe-— riod between April and September may be attacked in a few days — after they are felled, but the period of danger from a given species of insect may not extend over more than a few weeks. Thus cer- tain kinds of trees felled during certain seasons are never attacked, while if they are felled at other times and seasons the conditions for — attack may be most favorable when the insects are active, and then — the wood will be thickly infested and ruined. The presence of bark — is absolutely necessary for successful infestation by most of the wood- — boring grubs, because the eggs and young stages must occupy the in- ner and outer portions before the latter can enter the wood. Some ambrosia beetles and timber worms will, however, attack barked logs, © especially those in close piles or otherwise shaded or protected from rapid drying. A large percentage of the injury to this class of products can be prevented, as follows: (1) Provide for as little delay as possible between the felling of the tree and its manufacture into rough products. This is especially — necessary with trees felled from April to September in the region north of the Gulf States and from March to November in the latter, while the late fall and winter cuttings should all be worked up by March or April. (2) Do not leave the round timbers in the woods or on the skid- ways during the danger period, or, if this is unavoidable, take every ~ precaution to facilitate the rapid drying of the inner bark by keeping — the logs off the ground, in the sun, or in loose piles, or else, if possible, the opposite extreme =tunt be adopted and the logs kept in water. (3) Remove the bark within a few days after the trees are felled, from poles, posts, and other material which will not be injured byl checking or season cracks. (4) Take advantage of the proper months or seasons in which to fell or girdle different kinds of trees to avoid danger. Damage to products cut from saplings and left with the bark on can be prevented by transporting the material from the woods soon — after it is cut, so that it will not be left in piles or bundles in or near the forest during the season of insect activity. Damage may also be prevented by care not to leave the material stored in one place for several months. Pinhole damage to stave and shingle bolts cut during a warm season can be prevented by removing the bark from the timber as d z i sae ee ae ee - © & a # INSECT DEPREDATIONS IN NORTH AMERICAN FORESTS. 81. oon as it is felled and by converting the bolts into the smallest prac- Hicable dimensions and piling them in such a manner as to facilitate rapid drying. - Damage to unseasoned handle and wagon stock in the rough can be prevented by taking special precautions to provide against the same favorable conditions for attack as mentioned in connection with round timbers. This is especially necessary with hickory and ash if cut during the winter and spring. Damage to pulpwood and cordwood can be prevented to a great extent by placing the sticks of wood in triangular or crib piles im- mediately after they are cut from the trees, especially if the timber is cut during the danger period or must be held for a few months during the warm season. Peeling or splitting the wood, or both, be- fore it is piled will also provide against damage from insects. MANUFACTURED PRODUCTS. UNSEASONED PRODUCTS. Freshly sawed hardwood lumber placed in close piles during warm, damp weather in the period from July to September, inclusive, pre- sents the most favorable conditions for injury by ambrosia beetles. In all cases it is the moist condition and retarded drying of the lum- ar which induces attack. Therefore any method which will provide for the rapid drying of the lumber before or after piling will tend » prevent loss. It is important, also, that heavy lumber should, is far as possible, be cut only in the winter and piled so that it will ye well dried out before the middle of March. The damage to lumber and square timber when the bark is left on he edges or sides can be prevented by removing the bark before or mmediately after the lumber is sawed, or by sawing and piling the jaterial during the winter, or if sawed at other times it should be led so that rapid drying will be facilitated. | SEASONED PRODUCTS. Unfinished seasoned products—kInjury by powder-post beetles to ry hardwood lumber and other material in stacks or storehouses can * e prevented as follows: (1) Have a general inspection of the material in the yards and forehouses at least once a year, preferably during November or ebruary, for the purpose of (a) sorting out and destroying or other- ise disposing of any material that shows the slightest evidence of jury, as indicated by the presence of fine powdery boring dust, and b) sorting out and destroying all old and useless sapwood material any kind that will offer favorable breeding places for the insects. 6O 32. SOME INSECTS INJURIOUS TO FORESTS. (2) Prevent the introduction into the lumber yards or store- houses of any infested material, remembering that the insect may be thus distributed to or from all parts of the world. (3) Adopt a system of classification of all dry or seasoned hard- wood stock which will provide for (a) the separation of the pure heartwood material from the pure and part sapwood material; (6) classification of all kinds of wood most liable to attack, such as hice ory, ash, oak; (c) the successive utilization or sale of the older ma- terial (remembering that material one year old or over is far more liable to injury); (d) providing against the accumulation of refuse material in which the insects could breed; and (e) treating the best. material with linseed oil or kerosene to prevent attack. Finished seasoned products——Damage to finished handles, oars, spokes, rims, hubs, wheels, and other unpainted wagon, carriage, machinery, and implement stock in factories, wholesale and retail storehouses, and army and navy stores can be prevented by the adop- tion of the same general rules as those given under rough products. In addition, damage can be controlled and prevented in the following manner : Sort out and (a) destroy all articles showing the slightest evidence of powder-post injury, or (d) treat with kerosene oil such infested and slightly injured articles as may be tested for required strength and found to be of sufficient value for retention, placing the same in quarantine for a sufficient time to determine whether the treat- ment is successful. Damage by powder-post insects to many kinds of articles can be pre- vented and at the same time the material otherwise benefited by treat- ing the sapwood with linseed oil or kerosene, either by immersing it in the oil or by applying the oil with a brush, the application to be made as soon as possible after the articles are Eened from recently sea- soned, uninjured stock. PAST AND PRESENT CONDITIONS OF POWDER-Post INJURY. Up to 1906 there were a great many reports of extensive losses of valuable material from the ravages of powder-post beetles which were seriously affecting all industries involved in the manufacture, sale, and utilization of the classes of hardwood products affected by them. In response to these reports and accompanying appeals to the Department of Agriculture for information on causes and remedies, the problem was thoroughly investigated and specific advice and in- structions relating to practical methods of. control and prevention have been widely disseminated, both through publications of the Department and special correspondence. Reports of present conditions from our principal correspondents, together with the less frequent requests for advice, indicate that INSECT DEPREDATIONS IN NORTH AMERICAN FORESTS. 83 the disseminated information has been extensively utilized and that it has been worth many millions of dollars toward eliminating the Josses and reducing the drain on the limited supply of the kinds of timber required to replenish the damaged and destroyed material. The army and navy stores of handles, tent poles, wheelbarrows, oars, and many other hardwood articles have suffered severely from -powder-post damage, involving an enormous loss, but the carrying out of the information already supplied has evidently contributed _ greatly toward the elimination of this source of loss to the Goy- ernment. TAN BARK. Damage to hemlock and oak tan bark by the class of insects which ' in some cases has been so destructive to these products in the past can be easily prevented without cost, as follows: (1) Utilize the bark within three years from the time it is taken from the trees. _ (2) Prevent the accumulation in the yards and store-sheds of old bark and waste material in which the insects can breed. | These simple methods have been extensively adopted since their recommendation in correspondence and publications between about 1894 and 1904, and afford one of the most striking examples of the value of expert information on the peculiar habits of insects and of how millions of dollars can be faiied without cost through a simple UTILIZED PRODUCTS. Damage and loss from insect injuries to timber and other woodwork in structures of various kinds, to telephone and telegraph poles, posts, railroad ties, mine props, etc., can be prevented to a large extent through the adoption of the proper methods of management or of _ treating the material with preservatives before and after it is utilized. TIMBERS AND WOODWORK IN STRUCTURES. Injuries to timbers and woodwork in dwellings, outbuildings, bridges, etc., by powder-post insects can be prevented as follows: (1) Use nothing but heartwood for the concealed parts most liable (2) If it is necessary to use all or part sapwood material, attack ‘can be prevented by treating the sap portions with kerosene, coal tar, creosote, or linseed oil. Facilities for future treatment can be pro- vided wherever the rough or finished woodwork is exposed, as in i outbuildings, bridges, etc., if care is taken to expose the sapwood portions. ; 84 SOME INSECTS INJURIOUS TO FORESTS. (3) If the untreated timbers and woodwork in old buildings show evidence of attack, the affected portions should be given a libera application of kerosene. 4 Damage by white ants, or termites, can often be prevented in the following ways: (1) By the use of nothing but sound wood for underpinning and foundation timbers and the removal of decaying timbers from old structures. | (2) By preventing moist conditions of the wood in any part of the structure and especially that in foundation timbers. (3) By the treatment of timbers necessarily exposed to moist con- ditions with creosote, zine chlorid, corrosive sublimate, ete. | (4) Ifthe timbers become infested, further progress of insect dam- — age can be prevented by removing the badly damaged parts and soak- ‘ing the remainder with kerosene, fumigating with bisulphid of carbon, and by removing any adjacent decaying or other wood in which the insects have been breeding or may breed, such as logs, stumps, etc. : Log cabins and rustic work.—Damage by bark and wood boring insects to the unbarked logs and poles used in rustic cabins, summer houses, fences, etc., can be largely prevented by cutting the material in October and November and utilizing it at once, or by piling it off the ground or under cover in such a manner as to offer the best facil- ities for the rapid and thorough drying of the inner bark before the middle of March or the 1st of April following. If these necessary precautions are not taken, and there is evidence that insects are at work in the bark and wood, the damage can be checked by injecting - bisulphid of carbon through natural or artificial openings in the affected bark, and immediately stopping these and other openings with putty or a similar substance. Poles, posts, piles, ties, mine props, and similar products.—Insect damage to poles, posts, and similar products can be prevented to a greater or less extent by the preservative treatments which have been tested and recommended by the Forest Service for the prevention of decay. These should be applied before the material is utilized for the purposes intended, or, if it be attacked after it has been utilized, — further damage can be checked to a certain extent by the use of the same substances. It is often of prime importance to prevent injury from wood-boring insects, for the reason that such injuries contribute to more rapid decay. Therefore anything that will prevent insect injury, either before or after the utilization of such products, will contribute to the prevention of premature deterioration and decay. INSECT DEPREDATIONS IN NORTH AMERICAN FORESTS. 85 _ OTILIZATION OF NATURAL ENEMIES AND FACTORS IN THE CONTROL OF j * INJURIOUS INSECTS. Were it not for the natural checks and natural factors of control of some of the more destructive insect enemies of forest trees and _ forest products, artificial control would in many cases be impossible, and the depredations would evidently be far more continuous and complete. These natural factors m the control of the depredating insects consist of parasitic and predatory insects, diseases of insects, birds, adverse climatic conditions, etc. While one or more of these beneficial factors exert a continuous and powerful influence toward the prevention of a more extensive waste of forest resources, it has been repeatedly demonstrated that they can not be depended on to prevent widespread devastations or to otherwise work for the best interests of the private or public owner by protecting the best trees and the best tree species. The insects and birds which prey upon the depredating insects also have factors to contend against, consisting _of insects, birds, diseases, and climatic conditions. Therefore under normal conditions the tendency is toward the preservation of a bal- ance between the warring factors, but frequently the enemies of the trees get the ascendancy and take on the character of an invasion, which may continue for two or three or even ten years before the bal- ance is again adjusted through the influence of the natural enemies or diminished food supply. Thus a vast amount of timber or of a \ given forest product may be destroyed before the factors of natural control can prevail. It is evident that the most effective utilization of the factors of _ natural control will be through the alliance with them of the owner of the forest in the artificial reduction of the enemies of the trees rather than by efforts to make the natural enemies of the injurious insects his allies through artificial introduction or dissemination. The former is accomplished by the adoption of methods of combating _ the invaders which will reduce and weaken their forces below their power of prosecuting aggressive movements and attacks, or, as pre- viously stated, to reduce their numbers to the point where they must occupy a defensive position against their natural enemies and be dependent for their supplies of food and breeding places upon that _ furnished through avoidable mismanagement of the forests and manu- facturing operations. Thus the owner of the forest can contribute f greatly toward the preservation of a balance which will be to his _ material benefit. On the other hand, he may in the future, as in the past, contribute greatly to the multiplication of the depredating insects and to greatly increased losses caused by them, through neglect or a disregard of available information on the fundamental prin- ; I 356 SOME INSECTS INJURIOUS TO FORESTS. ciples of insect control in the management of forests and manufa turing enterprises. BENEFICIAL INSECTS. The beneficial insects comprise those which are internal or external parasites of the immature or mature stages of the injurious insects, and predators which feed on the young or adults of insects either before or after they make their attack on the trees or products. These two beneficial factors are doubtless far more effective in the long run than any other agencies of natural control. Yet they, in combination with all other factors, can not be always relied upon to render con- tinued and efficient control. They can, however, be relied upon to respond to artificial assistance in reducing the numbers of the depre- dators. BENEFICIAL DISEASES OF INSECTS. It is very evident that the parasitic fungi and bacteria which some- times cause epidemics.among injurious insects often exert a powerful | influence toward the control of extensive outbreaks or invasions o insect enemies of forests. Indeed, it appears that the greatest serv- ice rendered by this class of natural enemies is in the frequent sud den appearance of an epidemic which kills off a destructive species of insect after the latter has increased to such numbers and extended its depredations over such vast areas as to be far beyond the control of man or his insect and bird allies. Numerous examples of this kind of natural control are found in the sudden ending of widespread depredations by various species of caterpillars and sawfly larvee which defoliate deciduous and coniferous trees. As a rule, however, the beneficial effects of the diseases of insects prevail only after the injurious insects have increased to excessive numbers. Therefore this factor of insect control can not be depended upon to hold the insects in check or prevent outbreaks. The fact, however, that it operates on a class of insect enemies of the forest (defoliators) which at present can not be controlled by any known artificial methods renders the sery+ ices of the diseases all the more valuable. It is beheved that with further knowledge of nature? s method of propagating, perpetuating, and disseminating the diseases which cause epidemics among insects, they may be utilized more or less: successfully through artificial propagation and dissemination to prevent threatened invasions of defoliating insects. BENEFICIAL BIRDS. It is very evident that certain kinds of birds, such as woodpeckers,” render valuable service toward the natural control of destructive bark and wood boring insects. They appear to render the greatest » INSECT DEPREDATIONS IN NORTH AMERICAN FORESTS. 87 service, however, where but few trees are being killed or injured, because their concentrated work on such trees may contribute toward. the prevention of an abnormal increase of the insects. They also render some service as allies of the other beneficial factors which assist in artificial control. It is evident, however, that where many hun- dreds or thousands of trees are being killed the comparatively lim- ited number of birds in any forest under the most favorable condi- tions could have little or no beneficial effect. Therefore, while the birds should be classed among the valuable friends of the forest, and should be protected, it is plain that they can not, even with the utmost protection, always be relied upon to protect the forest against destruc- tive ravages of insects. We must remember, in this connection, that there are complicated interrelations between birds, injurious insects, and beneficial insects which do not necessarily always operate to the benefit of the forest. In fact, it may sometimes be quite the reverse. Therefore, in order to derive the greatest benefit from the conflict between the birds, the insect enemies of the trees, and the insect friends of the trees, we must utilize our knowledge of the factors which are contributing toward the preservation of a balance, so that whenever the enemies of the forest threaten to get beyond natural control we may enter the field through artifitial means and endeavor to force them back to their normal defensive position. BENEFICIAL CLIMATIC CONDITIONS. The benefits to be derived from climatic conditions which are det-. rimental or destructive to insect enemies of the forest, while some- times very great, are necessarily unreliable, and thus can not be depended upon to assist in artificial control. Im fact, the very con- dition which may contribute to the destruction of one ag may favor the multiplication of another. UTILIZATION OF WASTE CAUSED BY INSECTS. When we come to consider the vast amount of standing timber in the forests of the country which has been injured or killed by insects, and will go to waste if it is not utilized within a limited period, we realize that there are great possibilities in its utilization as a means of preventing the reduction of future supplies of living healthy tim- ber. It is all the more important that the insect-infested timber should be utilized, because in so doing we can contribute more per- haps than in any other way to the reduction of the insects to or below their normal numbers, and thus provide against serious injury in the future, as well as to the maintenance of control. 88 SOME INSECTS INJURIOUS TO FORESTS. PRESENT CONDITIONS AND OPPORTUNITIES. Unfortunately, the examples of management, or rather misman- agement, which are contributing to an extension or‘increase of waste are far in excess of those which under proper management are con- tributing to the reverse. This is due in a large part to the conditions © that have prevailed in American forests in the past that have ren- ~ dered it impracticable to adopt improved policies of forest manage-— ment, but at present it is largely due to a lack of appreciation of the — importance of the subject, and of the opportunities to prevent such — losses, when it is not only practicable but possible to do so, and when it will, at the same time, yield large returns on the necessary addi- tionalexpense. This is especially true in thousands of farmers’ wood- lots and private holdings in the States east of the Mississippi River, in which from 25 to 90 per cent of all of the serious injury of the © past can be prevented in the future with little or no additional ex- pense over that required for ordinary good forest management. FoRESt ENTOMOLOGY AS APPLIED TO AMERICAN FORESTS. It is only within the past eleven years that any attempt has been © made toward a systematic investigation of the insect enemies of the — forest trees and forest products of the entire country. The state of — knowledge of the subject previous to that time can be judged by the “fact that a number of the most destructive enemies of forest trees are — found to be new to science, and that nothing whatever was known of the habits and seasonal history of a large number of the more im- portant known species which are common enemies of forest trees and forest products, while scarcely anything was known in regard to practical methods of controlling the principal enemies of the forest and its products, or of preventing losses from their ravages as apphed to conditions in this country. PRESENT KNOWLEDGE, Within the past ten years forest-insect investigations have been con- ducted by the Bureau of Entomology of the Department of Agricul- ture in all of the principal forest regions of the United States, and have led to the following results: Results of investigations.—Satisfactory progress has been made toward the attainment of some of the fundamental objects of the in- | vestigations, one of which has been the laying of a substantial founda- tion for forest entomology in this country on which future progress can be made along the lines of acquiring, disseminating, and applying information of immediate practical value in the protection of our forest resources. Acquired and new information—tThe principal insect enemies of the forests and forest products of North America have become — INSECT DEPREDATIONS IN NORTH AMERICAN FORESTS. 89 known, and the general character and extent of their depredations have been ascertained. The more important facts in the life history, habits, and practical methods of control relating to some of the more destructive insects have been determined. _ A mass of original data has been collected relating to forest in- sects in general, including not only those which are destructive or injurious, but also those which are beneficial or neutral in their rela- tion to the forest, as represented by a collection of more than a mil- ion specimens of insects and their work. As a direct result of the investigations of forest insects during the past six years, at a cost of less than $53,000, there has been accumu- | lated a reserve fund of information now available through publica- tions, correspondence, and field demonstrations which, if properly utilized for practical application, would evidently prevent from 10 to 30 per cent of the annual losses at a very small cost. _ Disseminated information.—In addition to information dissemi- nated in all sections of the country through correspondence, lectures, _ demonstrations, exhibitions, etc., the published information, based ‘on results of investigations conducted by the West Virginia Agri- - cultural Experiment Station and by the Bureau of Entomology of the U. S. Department of Agriculture during the past eighteen years, is represented by over 1,300 pages, 99 plates, and 340 figures. (See list of publications. ) NEEDS. _ The work that has been done is only a beginning in the vast field of forest entomology. There is need of more systematic work (or so-called pure science) on the different stages of the thousands of species of injurious and beneficial insects involved. This is abso- lutely necessary in order to have the further scientific basis of facts on which to build the structure of complex details necessary to suc- cess in practical application in its broadest sense. There is need of further detailed study of habits and seasonal his- _ tory of the species of injurious and beneficial insects, as well as of the local and other conditions favorable and unfavorable for their mul- tiplication and work. Further information is desirable on the principal factors of nat- ural control of injurious insects, in order that it may be better util- ed to facilitate artificial control. There is special need of more general information and public in- terest in the subject of losses from insect depredations on standing timber and timber products, and a better realization of the possibility and practicability of preventing losses. Looking to this end, there is need of further demonstration and educational work along the lines which will bring the matter to the 61830°—Bull. 58—10——7 G0 SOME INSECTS INJURIOUS TO FORESTS. attention of the man in the woods, sawmill, factory, or trade who is in direct touch with the local conditions and business methods. | There is a special need of more experts in forest entomology, and there will be an increasing demand for such experts in the future, to organize and take charge of insect-control policies in state forests, in public parks, in the more extensive private or commercial forests, and in extensive manufacturing enterprises, and to give instructions © to students in forestry schools and forestry departments in state and — other institutions of learning. , The need of trained and experienced experts in forest entomology for all of this class of work can not be too strongly urged. There is perhaps no branch of economic or applied science which requires — more technical knowledge and practical experience as a basis for — proper investigations and authentic instructions and advice than | forest entomology, and there is perhaps no other feature in the | science and practice of forestry in which advice and application based — on insufficient knowledge is so dangerous. j There is quite a general recognition of the importance of guarding — against contagious diseases, of the necessity of consulting a physi- | cian in cases of serious illness, and of relying on authorized phar- | macists to fill the prescription, and then administering the prescribed treatment according to directions, but it is a notable fact that there are comparatively few persons who, even when deeply interested in ~ preserving the health of the forest, have heretofore recognized the importance of guarding against insect epidemics cr of consulting an ~ expert forest entomologist in case of a threatened or existing out- — break. It has often happened that when such advice has been sought © and received, the treatment was not administered according to the ~ recommendations but changed to suit the ideas of some one entirely | ignorant of the facts and principles upon which it was based. This © has often resulted not only in failure to accomplish the desired end, but has contributed to an aggravation of the trouble and increased ~ loss. The determination of the cause of specific troubles affecting the individuals of a given species of forest tree or an injury to a given 7 type of product is just as complicated and requires the same elements — of experience, training, and skill as that required for the determina- ~ tion of the cause of a given disease or the character of a given in- © jury affecting man. It is just as important to know the cause or — character of injury in the former as it is in the latter, in order to || prescribe the specific treatment which will vield the desired results. Therefore, in order to make the best progress toward preventing _ future waste of our forest resources from depredations by insects, © | every one interested in the subject, and especially those in authority in the public and private institutions of investigation and learning, © should see to it that the instructions to students and the information | hk | . i INSECT DEPREDATIONS IN NORTH AMERICAN FORESTS. 91 given out to the public is not only the best available but that it is limited to the range of expert knowledge of the subject possessed by | the instructor or investigator. ELEMENTARY AND TECHNICAL KNOWLEDGE OF FOREST ENTOMOLOGY FOR THE FORESTER. While it may be desirable that every professional forester should have an expert knowledge of forest entomology, it is rarely possible, even under exceptionally favorable conditions, for him to acquire more than the necessary elementary knowledge, and even this has not been possible under the conditions which have necessarily prevailed in the forest schools, and in the practice of forestry, in this country. Little or-no time has been available for acquiring the necessary in- formation from subsequent study and practical experience. There- fore this feature in the education of the American forester has been practically neglected. PRESENT REQUIBEMENTS OF INSTRUCTION. As long as expert forest entomologists and authentic text-books based on American insects and conditions are not available for giving a complete course in technical and applied forest entomology the requirements of such a course should be limited to instruction in ele- mentary entomology, and in elementary principles of applied forest entomology, which will give the necessary foundation for intelligent observations and utilization of available information as required in future practice. CONCLUSION. There is conclusive evidence that insects have been in the past, and are now, important factors in the waste and reduction of timber _ supplies, and will continue to be such in the future (pp. 57-58). They attack perfectly healthy trees of all ages and kill them (p. 58). They have at times killed a large percentage of the best timber over thousands of square miles of heavily forested lands (pp. 58-60). They reduce the value of living timber and that of crude and finished products (pp. 60-66). The accumulated evidence through many years of investigation and observation in the principal forest areas of the entire country by the writer and the field assistants in forest insect investigations furnishes .the basis for the following summarized statements and estimates: A large percentage of pine and spruce timber was killed by the southern pine beetle in 1890-1892 over an area of 75,000 square miles in West Virginia, Maryland, Pennsylvania, Virginia, and North Carolina (p. 58). 99 SOME INSECTS se TO FORESTS. Billions of feet of matured spruce have been killed by the eastern spruce beetle during the past half century in the northeastern United | States and southeastern Canada (p. 58). . A large percentage of the matured Engelmann spruce of the Rochy Mountains region has been killed by the Engelmann spruce beetle within the past fifty years (p. 59). : A large percentage of the pine timber of merchantable size in the | Black Hills National Forest and other national and private forests of the central Rocky Mountains region has been killed during the past ten years by the Black Hillis beetle (p. 59). A large percentage of the best-matured pine timber of the region north and west of Colorado and Utah has been killed within the past — twenty years by the mountain pine beetle and the western pine beetle (p. 59). | A large percentage of the matured Douglas fir, or red fir, of the Rocky Mountains region has been killed by the Douglas fir beetle (ys:D2)).. The supply of hickory timber in the forests and woodlots of the States east of the Mississippi River has been greatly reduced by the ravages of the hickory barkbeetle (p. 60). Practically all of the matured eastern larch has been killed over © vast areas in the northeastern United States and southeastern Canada by the larch worm and eastern larch beetle (p. 60). The wood of living timber has been rendered defective by wood- boring insects to such an extent as to reduce the value of a vast amount of standing timber from 50 to 75 per cent (p. 60). Rapid deterioration of the wood of dying and dead trees has been — caused by wood-boring insects, often amounting to from 25 to 100 per cent during the period in which it would otherwise be available for utilization (p. 62). ; Crude manufactured and finished forest products have been dam- — aged by insects to such an extent as to cause an estimated average annual loss of 10 per cent of its mill value (pp. 64-67). _ Insects are the cause of greatly reducing our forest resources by killing the inaccessible timber; by reducing the quantity through injuries to the wood of living and dying timber; by preventing nor- — mal reproduction and development of future ones and through - destroying forest products. GENERAL ESTIMATES OF AMOUNT OF DAMAGE CAUSED BY FOREST INSECTS. The results of extensive observations during the past ten years in* the principal forested areas of all sections of the country, and during — an additional eight years in West Virginia, indicate to the writer that the amount of standing timber killed by insects, together with ES ry Oe ae INSECT DEPREDATIONS IN NORTH AMERICAN FORESTS. 93 the standing living, dying, and dead timber reduced in quality and value by them in the forests of the country, to be found at any given | time, has been not far from 10 per cent of the total stand of mer- chantable-sized timber (pp. 70-71). Considering the forest in its broadest sense as a source of national _ wealth of a given value for all purposes, including direct utilization, protection of land from erosion, protection of headwater streams, protection of game, and as contributing to the real and esthetic value of health and pleasure resorts, it is evident to the writer that the total damage caused by insects has been equivalent to an average addi- tional 5 per cent of the value of the merchantable-sized timber of the entire country (p. 71). Considering the problem of insect damage to standing timber and crude products on the basis of direct utilization of the forest re- sources, it is evident that the reduction in value below that of healthy timber or sound products at the time of utilization, including losses from handling defective material, has amounted to an equivalent of at least 10 per cent of the average annual mill value of the aggre- gate output of forest products of all kinds. This, of course, includes the killed and damaged merchantable-sized timber considered under the estimate relating to standing timber, given above. Since the killed and damaged standing timber is involved in any given annual output, this estimate on a basis of utilization represents more nearly a direct reduction in cash values (p. 71). The writer estimates that the annual loss caused by insects injuri- ous to finished and utilized products, including the consequent in- creased drain on the forest resources to replace that prematurely de- stroyed by insects, is equivalent to at least 3 per cent of the original or mill value. | HOW LOSSES CAN BE PREVENTED. The results of extensive investigations and of practical applications during recent years have demonstrated that some of the most de- structive insect enemies of American forests and of manufactured and utilized products can be controlled and serious damage prevented with little or no ultimate cost over that involved in good forest man- agement and business methods. It is evident that if the information now available through publica- tions of the Department of Agriculture and through direct cor- respondence with its experts is properly utilized in the future it will result in the prevention of an equivalent of at least 30 per cent of the estimated annual waste of forest resources that has been caused by insects within recent years and thus contribute greatly to the conservation of the forest resources. This can be accomplished as follows: 94 SOME INSECTS INJURIOUS TO FORESTS. (1) By the adoption or adjustment of certain requisite details in | forest management, in lumbering and manufacturing operations, and in storing, transporting, and utilizing the products which, at the least expense, will bring about the necessary reduction of the injurious insect and unfavorable conditions for their future multiplication or destructive work. (2) By the adoption of policies of control, based upon expert tech- nical knowledge or advice relating to the species, habits, life history, and natural enemies of the insects involved, and methods for their control, supplemented by expert knowledge or advice on the prin- ciples of technical and applied forestry in the proper management, care, and utilization of the forest and its resources and still further — supplemented by practical knowledge and experience relating to local conditions and facilities favorable and unfavorable for suc-— cessful application according to a given method or policy of control. (3) By reliance on technical advice furnished by recognized ex- perts in forest entomology and forestry as a basis for success in prac- | tical application by the owner or forester. (4) By utilization of so-called matured timber, and especially dense or pure stands of such timber, thus removing one of the favor- able conditions for rapid deterioration through attacks by wood- boring insects or death through the attack of destructive bark-boring or defoliating insects. (5) By the utilization of a knowledge of the principles of natural control as a means of contributing to the efficiency of artificial control. (6) By prompt recognition of the first evidences of the work or destructive outbreaks of the principal insect depredators, by authentic — identification of the species involved. and by prompt action in adopt- ing the proper method or methods of control for the prevention of — losses. It should be remembered that as a rule it is useless to attempt the extermination of an insect enemy of the forest or its products. It is — only necessary to reduce and weaken its forces at least 75 per cent, so that it can not continue an aggressive invasion, but must occupy a defensive position against its own enemies and become dependent upon favorable conditions resulting from avoidable negligence and mismanagement by the owners of the forests and the manufacturers of forest products. While beneficial insects, beneficial birds, and: beneficial diseases exert a continuous and powerful influence toward the prevention of a more extensive waste of forest resources, it has been repeatedly demon- strated that they can not be depended upon always to prevent wide- spread devastations or otherwise to work for the best interests of the private or public owner by protecting the best trees _ the best tree species. INSECT DEPREDATIONS IN NORTH AMERICAN FORESTS. 95 F The best way to utilize the factors of natural control is to become _ their allies and assist in the reduction of the enemy, rather than to | try to make them our allies through artificial introduction or dissem- ination. A large percentage of the waste caused by insects can be prevented by the utilization of infested material, and at the same time, without _ additional expense, this will contribute gr eatly to the control of insects _ which cause such waste and also’prevent injuri ies and depredations in _ the future. Under past conditions the poor management or neglect of the average forest has contributed to the increase of depredations by insects. Under present conditions of better management of local forests and of the more progressive manufacturing enterprises much is _ being accomplished toward the reduction of losses. In the average forest, and in the average business enterprise dealing with forest _ products, present conditions are little better than in the past. This is largely due to a lack of appreciation of the importance of the sub- ject and failure to realize the opportunity and practicability of pre- _ venting a large percentage of the loss. a a a 1831. 1876. 1878. 1882. 1882. 1885. _ 1884. 1884. 1885. 1887. 1888. 1889. 1890. 1891. 1895. 1897. 1898. 1899. 1899. _ 1900. 1901. 1904. Fyrtes, THomas W.—Nematus erichsonii. A retrospect. <22d Ann. Rep. PUBLICATIONS RELATING TO FOREST INSECTS. HISTORICAL AND GENERAL. WILSON, ALEXANDER, and CHARLES LUCIEN BONAPARTE.—American Orni- thology. (Robert Jameson.) Edinburgh. Vol. I, pp. 183-134. Peck, C. H.—The black spruce. <(Trans. Albany Inst., VIII, pp. 283-301. Peck, C. H.—30th Rep., N. Y. State Museum. Hoveu, F. B.—Report on Forestry, submitted to Congress by the Com- missioner of Agriculture, Part VIII. Insect Ravages, pp. 259-274. 1. The injuries done to spruce and other coniferous timber by insects. StretcH, R. H.—Notes on Pieris menapia Felder. yl ata en 33-34 Ger aRerR: MELIVILY: 2255 Sooo on ee oo ks 31-32 proms, eters mye TOW. oo een 5 oe a wine en es 36 a ee ee reas Stes Bn a ie a Wieeemaeeni, qepeetrsaiittee oo Soe ea foie sence 3 Se I St re eh oe 11-13 enna tee te oe en he ee Sr et 35-36 ey. Sate aha eel Se eee | Sok feu As aes eee a 1 observations by A. D. Hopkins, 1890-1905............-------- 7-9 oe skewed ve 9-11 ; members of Forest Service. ...........------- 4 ORs ee ers Se BO Nae Ry a alates Sula av 8 publications retating thereto, fist... 2. = ..-.------.---- 15-16 published data, review-...... ORE ee tn cd ers he 4-6 oe Mage ae, adh lh SDE. Piece corny. ee Claes 6-7 NRE MIRON Dee ce. ee Ro il vine ee A ino wp ae me we 31-32 variation between different latitudes and alti- REO eS Seca e CN Cos ce eh ee 32 Cypress, injuries to wood of dying and dead trees by pinhole borers or ambrosia Nr ts Se Oe Ets asin ys Bean She oye a He Gli <> nem as x oa 63-64 Decay following injury by forest insects........ pete ato sas ateaers$ Deck 69 Th Paply nag Set ol ra Dla] a a ae 17-30 RE ee oud ars Goo arse cok oe tea ood en a 27 , causes death of sugar pine, silver pine, western yellow pita, Od todeetiore PIG... 252 ks sn 59 RN ee io nen wie pe ss en 18-19 NT cae pawns ed 18-19 61830°—Bull. 58—10——8 ee eeere ees —EEEEEEE——E——E————— .- ' 106 SOME INSECTS INJURIOUS TO FORESTS. Page Dendroctonus brevicomis, combating, first reeommendations..........-......-.. 27-38 methods: . 4. Ss5)..9¢ ae ne eee ee 27-30 damage, extemt?) 22.20%) 4.2. 2 Se eee 19 death of pine resulting therefrom.!5?22)-— 332232-5--- 18 distribution 2222.22.22 2 a eee 19 early history i¢.02 lees 4. 2 4 dee ee ee eee 20-21 first generation. 25. '. 2. 2 ye eee ee 23-24 habits. 02... A eee 25-27, 29 hibernation® <2 42222 ‘5 a > wih aR ese eae ee Be insect enemies! s.2.. 2... oe eee ee oe ae life history “-2)\.3.5 2.02 oS eee 23-25, 29 losses; extenti.<:'4- se. 265 eee eee eee 19 prevention, possibilitigs Bhs \ayetabe sth oe: PATA MN 19 yMatural enemiess.....4.. 4.-)24). yee eye ee = 27 observations by A. D. Hopkins, 1899-1904 ........... 21-22 H. EB. Burke 1900s go ee ee 22-23 J. Li Webb; 1905. er s355-42- 5 eee 23-27 publications, lish. <2. ¢2 = oo eee Pues A Rentees 30 remedies; summary... 2.522 4838425 eee eee 29-30 second generation : 2. .... 255.4 252s eee eee ee eee 24-25 summary of habits... : 222.3 5se Gee Seeee eee 29-30 hie history. s..# 455 see eee eee ee 29-30 remedies... 22 ...)2 Daa eae eee vee ae hel 29-30 engelmanni causes death of Engelmann spruce............--.---- - 59 frontalis causes death of pine and spruce...........--.-.-------- 58 monticole causes death of sugar pine, silver pine, western yellow pine; and lodgepole pine. .2.222 222.25. 255. ae eee ee eee 59 piceaperda. causes death of spruce. +2522 - 3 sees eee eee 58-59 control, successiul, example. 2322-2). See 75 ponderosx causes death of western yellow pine.......-.....-.-.--- 59 control, ‘successful, examples’: 2 oes sea tae ae eee 76-78 pseudotsuge causes death of Douglas firs). 42552 5222242-2 4 eee 59 terebrans, Injuries to wood of living pines: 2-25 2- - 2 s--see44 sees 62 valens, injuries to wood of living pines: 2-4-22e4-5e5-ceeee ee 62 Dipterous larva in mines of Cyllene robiniz......--- Tg OS Pee J en eae 35 Diseases in control of forest. sects... 22 2..2- 22.2 ese See eee ae 86 Douglas fir beetle. (See Dendroctonus pseudotsug2.) Mlaterid enemy of Cyllene robimiz: ... .2...-5...2450 02 eee ee eee eee eee 8 Elm, injuries to wood of living trees by Corthylus columbtanus........--.----- 61 Entomology, forest. (See Forest entomology. ) : Hupsalis minuta, injuries to wood of living oak trees........-....-..---------- 60 Kelling infested trees'to control barkbeetles: 2: 222 225 es eee eee eee 74 trees at proper month or season to prevent injury from insects that infest crude forést products. 002 2.4 2.5.44 0254 eee ee 80 to prevent injury from insects that infest dying and dead wood... 79 Fir beetle, Douglas. (See Dendroctonus pseudotsug2.) Mouglas, killed by Dendroctonus pseudotsuge-- 23. - se ee 59 pul pwood,injutiestby msects..2 2... .'.... 2/55. e eee 65 Bare-lalled timber injured by insects. ........... 223.92 22 eee 68 Fire not recommended against Southern pine sawyer. .........-- Us, ok aya 54 Fires, forest, and forest insects, interrelations.......... Sak os RE Rik > 67-69 as agency in destroying forest insects....... gad 5, arr 68-69 losses therefrom . 224.2202. ee Ss oe 67 private, control of barkbeetles therein..........................---. 7 EE 74-75 INDEX. 107 Page area, insect-killed timber as fuel therefor.................2-2-0-0020-2220000%- 68 Forest entomology as applied to American forests..........-........----2------ 88-89 present knowledge ........-- 88-89 elementary and technical knowledge needed by forester. . . . 91 oe eS hE EE AS a le ee 89-91 present requirements of instruction ..............---.-.---- 91 fires. (See Fires, forest.) insect investigations, information, acquired and new.................- 88-89 TennImEMePS 2 2.1/2: 4. FIOT 89 Cl Ba oS eee eras 2% 88 insects. (See Insects, forest.) en peicw: Crude, imjiries We aMBerii: 225-560) 2... 2.2.2.2 64-65 US re: 79-81 finished, injuries by powder-post beetles...............--..-. 66 prevention.........-. 82 reduction in value through insect 2 es SAS 71 seasoned, injuries by insects, prevention. i 82 in yards and storehouses, injuries aliy powder-post beetles.............-...-- 66 injuries by insects ............-..- Be a Ee ee 64-67 (OS 8 ee oe Slot ya ee nee 79-84 manufactured unseasoned, injuries by ambrosia beetles and other wood-borers. . 65 : insects, prevention . . 81 ’ unfinished seasoned, injuries by insects.......--.-:--------- 66 prevention .........-. 81-82 PRATER Aero We SREP IS es oo es = SS. | - 66-67 preweniamrite ss. U2: Pike ccnp. 83 PGnGmiagm. Bbiames Hy iisecis. .. .--. 2) cepu ase Be ests. 2 he. eds 67 prevention euoreee A. . .222258-221. 22.2 79 resources, publications relating thereto...............--.-------------- 100 statistics, publications relating thereto.........-.-.-.- aS stent Forester, need of elementary and technical knowledge of forest entomology... 91 Forests, inaccessible, natural control of barkbeetles therein................-. 75 national, control of barkbeetles therein .......:..................-.--- (4-75 North American, forest entomology as applied thereto ---.........-.-- 88-89 insect Meprenamemmsue ts jad S. OF). he. Utell 22 Te 57-71 and practical methods of preven- is, i CONOl... 632-2222 52 57-101 and practical methods of preven- tion and control, conclusion ... 91-95 re i es RE I a SE 57-67 control, general principles - .. . . - 72-73 UMN 5 oes <3 a Sad 71-91 ANE ca ial aa Se a Aen 57-67 prevention methods -..........-.- 79-91 reduction in cash revenue there- je eee cioagty Gates 71 nation’s wealth thereby ......... 71 present knowledge of forest entomology as’ applied cg oe 2 OS Sy eee ee 88-89 ow 108 SOME INSECTS INJURIOUS TO FORESTS. Page Fungi, forest, and forest insects, imterrelation\. 22,2202. 24) ae eee ee eee 69 Fungous disease of Cyllene robinix.-. 22s) 2 o25-2oee ee 5 ee 36 | Fungus, wood-staining, following work of ambrosia beetles in conifers......... 63 Furniture, injuries:b y powder-post beetlesi2= 4: 52-2: 522 yeaa eee eee 66 Girdling trees to avoid injuries from insects that infest crude forest products. . 80 Golden-rod flowers attractive to adults of Cyllene robinix............ 2,6, 7, 13, dae ‘‘Grease spots” in timber caused by Corthylus columbianus.......-..-...--.:.-. 61 Gum, manufactured unseasoned, injuries by Pterocyclon mali...............-- 65 Handles, finished seasoned, injuries by powder-post beetles.................- 66 prevention. -.....- 82, 83 in the rough, injuries by ambrosia beetles and roundheaded borers . - 65 insects, preventiont 2.24/45. 2 sce: 12d pomder-post beetles>--2: Sasa =e ee 66 Hardwood trees, insect injuries to wood of those dying and dead..-........... 64 Hemirhipus fascicularis, enemy of ‘Cyllene robiniz ._--— -- = 32s ee eee 35 Hemlock tanbaxld injures: bynmsecisesas 2:2 t 2 ae eee ee ee eee 66 prevention: ..eaeee soe dak Cees 83 Hickory barkbeetle. (See Scolytus quadrispinosus.) bolts, injupies by, Iaseetes, Jac SGN AAS? We. 5:6 See eee 65 handle and wagon stock, unseasoned, injuries by insects..........-- 65 prevention. - 81 handles, finished seasoned, injuries by powder-post beetles............ 66 prevention. . 81 heop-poles; injuniestby msects.....~..- 24.22 es ee ee 65 injuries to wood of dying and dead trees by insects.........-- 64 products, seasoned, in yards and storehouses, injuries by fami aaa beetles... 205.5. 2. RL ees. Sk ee 66 trees killed by Scolytusquadrismnosus:.2 =. 234s eee oe ee eee 60 Hop-peles, hickory, injuries by insects. 2...) de. 9 See ee ee 65 Uopkins, A. D., paper, ‘‘ Additional Data on the Locust Borer (Cyllene robiniz Forst:)??. 0-2. , Set) Seen vee 31-40. ‘Insect Depredations in North American Forests and Practical Methods of Prevention and Control”... ._. 57-101 ‘“The Locust Borer (Cyllene robiniz Forst.)”.......... 1-16 Hubs, finished seasoned, injuries by insects, prevention..............-.....-- 82 Implement stock, unpainted, injuries by insects, prevention..-......-........- 82 Insect. depredations in North American feresisiss25) 3 99ene 29 eee 57-71 and practical methods of pre- vention and control... ... . 57-101 and practical methods of pre- vention and control, conclu- SIOM. G.. yee oo ee ee 91-95 character... 725.8: fe ae eee 57-67 control, general principles. ... 72-73 methods: 2 =. 44eeeae (diss damage therefrom, general esti- mates of amount Geese esos 92-93 damage therefrom, summary and estimates as to charac- ter andextent > = ee eee 69-71 Oxbeniticince = ker eee pega a. 57-67 prevention methods........-- 71-91 reduction in cash revenue - thereby. .2:3 4 ee ee ce sin Renn al RE {2 ee Ap teniamne INDEX. 109 Page. - Insect depredations in North American forests, reduction in Nation's wealth SE I 2 ROI RE oo on onan ee ais awd ew thee ahy ee eens as's 7 Sanne it eI CONNIE os i ow ap wie ote Pa and ise dea rag 35 WP TNOIIEORUS 2 a ee Sb ee seed 27 ERNIE a wn ini dss on Foe 53-54 ee ee ee ener re 64-67 MRNA oe Oh ra. ae to le 79-84 natural and artificial tree reproduction................-.-.---- 67 prevention. 3 2 79 North American forest products, general eainmbesti ofamount.. 92-93 reduction in value of fi ished and commercial are ucts thereby .- ig 71 summary and estimates as to character and extent...__. 69-71 wood. ef dying: and dead teres (27. Ws suns 222. = - 2 et 62-64 (5 mes Be 78-79 Timea ieCes Ss... wa nS Beet ee dy 60-62 preveniign: seas Ste 2S 7 ele peer eet tories... Fe Ue ee. J). ee 68 ARE es Sea: obi os er ee Br 69 eestawian tie oad Griteds. |. 3... ke Se, es se Se 58-60 Sin Ane RCRN eS 693). 7. 22s)... ee, 90k. 68-69 EN EE | ee: : a eS 86 estimated loss of standing timber killed and damaged thereby... ..-... 7071 forest (see also Insects injurious to forest and forest products). injurious to forests. (See Insects, forest.) and forest products, control by utilization of natural enemies and factors.. 85-87 general principles . . ... 72-73 reetthads. 2. bisud. yuo 71-91 damage, general estimates of metre, . cen ul. . 2.25 - 92-93 damage, summary and esti- mates as to character and BESAMNGIG ad Bua 69-71 information, acquired and NR oe on sg 88-89 disseminated... - 89 prevention of losses. ........ 71-91 gud. forestsares) ieterrelationsa) =. ole... -.---------- 67-69 pump gmabterrelation i) is seeB uta... 2-2-2 69 control by utilization of natural enemies and factors. - .-.......... 85-87 present conditions and opportunities. ................. 88-89 mea, saealietiunates . 222925 ete = 5 ses ls 2 oe 92-93 samenreOlneenbe MeCAY 2 «bn oc eh eens rode Soe. ~~ - 25 69 edete Billed timbers od 5s5e., . isa ses. Sos - hes ee tt 68 in their relation to the reduction of future supplies of timber. -.. 67 ipa ieaiOie, teeGliiadreS Her. 4! wales. 2. 88 losses therefrom compared with losses from forest fires ..-..... 67-68. prevenmison, summarysced...-....--...---.-.-. 93-95 results of Me maior is foe OT Tr PAS 58 ets ss 2 88 utilization of waste caused deine een om i) eet... sued <2 87 4 b { en See ene 110 SOME INSECTS INJURIOUS TO FORESTS. Page. Insects injurious to forests and forest products, prevention of losses, summary.. 93-95 publications relating thefeto!.'. ch 2ices Shee ee 96-100 reduction in cash revenue there- Dyes icc ie (eh Nation’s wealth thereby...-.- (fi which cause defécts in living timber, control: 22 552222588-- 2222-22. 78 Ips, enemy, of Cyllene:robiniz -....-2-.-- 22 222-2 35 Kerosene against powder-post beetles: : 902-7145 1272/4 = ete ee ee eee 82, 83, 84 Germitese jess snc. 2. Ses BAS oe ee oe 84 locust borenls.. sc. 22.40 0-.26)< oe Ae ae ee 37-38 Lamia carolinensis, bibliographic reierence . 442/222 sep eee ee 56 = Monohammus titillation . 20... 52..2 Se ee ae ee 42 denidior.,,pibliographice relerence. <2... 50-2. eer eee ee 56 = Monohammus trtillaton. 222)) 1728 eae ee eS es eee 42 fitillator, bibliographic welerences: = =.= -- 22> 2 epee eee ee 56 == Monohammus hitllator......- 93924 GER ee eee eee 42 larch. killed: by Nematus erichsom2ea295 720-0 -- = = oes ee ee 60 worm. (See Nematus erichsoni.) Lightning-struck trees, menace to healthy forest........0./20.-......--..-.--- 30 iainseed oil against powder-post, beetles... - . ....-... -5aae ye eee Ae eee 82, 83 Locust, black or yellow, destruction of trees and wood infested by locust borer. .....2.5..2+.. 422 SER ee UE A hosttree of Cyllene robe. asa See 1-16, 31-40 injuries to wood of living trees by Cyllene robiniz. .. - 61 plantations, extensive, preliminary requisites to : avoid damage by locust DOrerns Vee. MEARS So 12-13, 38-39 proper locations to avoid damage by locust borer.. 12, 38-39 subsequent management to avoid damage by locust boreres2es gah Ge Fe 0 Ot 13, 39 propagating borer-resistant trees. ......------- 13-14, 39-40 spraying trunks and branches to kill young larve of locust: borerss.,J2 3200 8 3 oes are eee 37-38 time to cut, to destroy young larve of locust borer.... 36-37 borer. (See Cyllene robiniz.) Log cabins, injuries by bark and wood boring insects, prevention... ...-.---.- 84 Lymexylon sericeum, injuries to wood of living chestnut and oak trees. .......- 60-61 Machinery, finished woodwork, injuries by powder-post beetles. ...........-- 66 prevention... - 82 Mahogany lumber, myuries\by Pterocyclon mali. .:--.2 5222s ee eee 65 Minelprops,injuries!by-imsects»prevention. .-.... ..../- 242 5a eee ee 83-84 unseasoned, injuriesiby imsects... 5... 66 utilized injuriesybyiamsects;: ..- 2. 252... ee ee 67 wath bark on. tajuries by insects. 2 22..)..2 260) ase ee ee 64-65 Monohammus dentator, bibliographic reference.................-.------------ 56 = VMonohammus titillator. 25-2. 34 eee 42 nuimor bibliopraphie reference... 2:....20 22) aes 56 == Monohammus tittllator: ... op ee er 42 INDEX. 111 Page. Monohammus scutellatus, bibliographic reference . ......-..------..---------- 56 ng Gere eG Ser OEE CLE ee ee Pee 41-56 Spare, eee fe 825 eo See Se bocscee ee. 45 8 Rg oo eS Cpeiiy ee ate? ee a 56 PEC EIN Cee. ca oe Se Pe 45-49 Pamison tn treen meecked 620208 6S oe eee 43 SUMMERS ara eT Foe So oc wee Po Wego OMe make sms 43 Dn aE eg hr are ae mer ree 45 Me ere te, ee es oe in sp eae 51-53 Pn eas es So. 2 a a ee ee 42-43 ET eg ee ple ea a ee a 43 injury to, eterm-felled timber. ...-2-......-----.---..- 44 | ee ama aedy Sa ee 45, 47-48 ee. ee Se gs ae a go 45 Spee ee er re rt 53-54 Pe ee ee oe ns 8 ee 48-49 oe el 0 Ee a 54-56 cg Se ee ea ee 56 nT OE ae eS EE ene EY EN, MM Ete soe oes oS 3 Eee .-- 2 2 ---- eo 5,6 Natural enemies and factors in control of insects injurious to forests and forest Oe BEEN CR ied op) RE ee are ee 85-87 eae bee Reereeth ere igh 8 is Ds ss 2 22 ewe Le! 89-91 Nematus erichsoni causes death of large trees. ............--------------------- 60 Neophasia menapia, defoliation of pine followed by work of Dendroctonus brevi- ee Msi 2 RE? so pe ie SE Sa 2 20 Oak, injuries to the wood of dying and dead trees by imsects..............--- 64 living trees by Eupsalis minuta...........------- 60 manufactured unseasoned, injuries by ambrosia beetles.................- 65 red, injuries to wood of living trees by Lymerxylon sericeum..........-.-- 61 Reayreeeeee 3 eke 61 rock, injuries to wood of living trees by Corthylus columbianus.........- 61 seasoned products in yards and storehouses, injuries by powder-post en enne ne hee a ree Se gest Ss) > eee eee so ck SE 66 nny mneiner te aeetino gS 2e oye eee 2 2 oe 66 Payee erent. 2 fo. ns 83 timber worm. (See Eupsalis minuta.) white, injuries to woed of living trees by Corthylus columbianus.........-- 61 Ee eee ee 61 Oaks, injuries to wood of living trees by Lymerylon sericeum..............---- 61 ; PemmuIEWNOMN 4. 44). 24 -- =. ee 61 nnn eis cemenen as Wi SEIEER / SIAWONIEIGR, 20,0. 02. )-~~---~ «02s eslsi-a leis le 82 powder-post beetles, prevention. . ods regi 83 ‘“*Patchworm” in timber caused by Corthylus iiliciadidae.. Sos eee xe 61 yy se S4 Pine beetle, mountain. (See Dendroctonus monticolz.) southern. (See Dendroctonus frontalis.) western. (See Dendroctronus brevicomis.) d butterfly. (See Neophasia menapia.) destruction by Dendroctonus brevicomis.................-----+.----.----.-- 17-30 ES Se TAGE ae Oe 41,43 eg ST le, a 58 loblolly, injuries to wood of dying and dead trees by ‘‘sawyers”........ 63 112 SOME INSECTS INJURIOUS TO FORESTS. Pine, lodgepole, killed by Dendroctonus brevicomis...-..--...----------+------ monticols ..... 5... Ree ee longleaf, injurious to wood of dying and dead trees by “‘sawyers”......- sawyer, southern. (See Monohammus titillator.) shortleaf, injuries to wood of dying and dead trees by “‘sawyers”-......- silver, injuries to wood of dying and dead trees by “‘sawyers”.........-- killed: by Dendroctonus brevicomis — 55-3) eee ee MONECOL sc -3sbo ole: eee eee er eee sugar, host tree of Dendroctonus brevicomis:...- 2p ne injuries to wood of dying and dead trees by “‘sawyers”.......... killed by Dendroctonus breviconis. 223 oe -) PROTNCOLR wim ints oA oR eS trees, hosts of Monohammusiitillator...2-- <2e es) eee ee weevil, white. (See Pissodes strobt.) western yellow, host tree of Dendroctonus brevicomis..........----------- 20 killed by Dendroctonus breviconms=--2-- = 22 220-2. eee 59 MONLICOL ae met oe 59 PONAHOSR oo Ne ee 59 white, injuries to wood of dying and dead trees by “‘sawyers”.......... 63 living trees by Pissodes strobi..........-..--- €2 yellow, injuries to wood of dying and dead trees by “‘sawyers”.......-.- 63 Pines, injuries to wood of living trees by turpentine beetles (Dendroctonus walens and D: terebrans)oi..2032025 20. 228s. - 8 eee ee eee 61-62 Pines, injuries to wood of living trees by turpentine borer (Buprestis apricans).. 61-62 Pinhole borers, injuries to wood of dying and dead cypress......-...---..---- 63-64 damage to stave and shingle bolts, prevention.........-.....-.-..--- 80-81 Pinus echinata, host treeof Monohammus titillator. 2+. ce J 22a ee a ee 42 mitis= Pinus ech noe nou oe en reo E Sy. tt at's ee hdl ee hs 2 Le 19 Spokes, finished seasoned, injuries by insects, prevention..............----.--- 82 Spruce beetle, eastern. (See Dendroctonus piceaperda.) Engelmann. (See Dendroctonus engelmanni.) Engelmann, killed by Dendroctonus engelmanni...........------------ 59 malice try Dendroctonmapromiauts..» 222. =. 2 5222 oo2- 2 2 og ee = 2+ -oe- 58 ON eg a 7 a 58-59 pie ere itigiried sy Amiseeis. 2.22.22) 222 lee ae be a - 2 65 Stave bolts, injuries by ambrosia beetles and timber beetles..........----.---- 65 IAEA PLOVPIEION | 2: asec eu es aha) - = ~- 6+ 2-2 - 80-81 storm-felled. trees, menace to healthy forest.......-.--.-2..+--:4---+-------- 30 Storms, cause of vast destruction of pine timber by Monohammus titillator. ... 41-43 Submergence of logs as remedy against southern pine sawyer.-...-....-...-.-.--- 5d unbarked infested logs to control barkbeetles..........-..--.-- 74 logs to prevent injury from insects that infest dying ee ee ee ee 79 WOU he Reena y Sie IG IGE Saco ie hoe oS Spe case hs Sr ne 12 Summer cutting of pine undesirable in regions infested by Dendroctonus brevi- er ae ee aA re ee es eae Pos eae SC ek A SS 30 Beet, Batiadets tin SHROC Mer Soo So dey fe pip nk folie 66 hn ee ia kn an 83 Tent poles, injuries by powder-post beetles, prevention................-.-.-- 83 im Termites, injuries to timbers and woodwork...................--.------+----- 67 SS se ee ee ee 84 ““Tickler, long-horned.’’ (See Monohammus titillator.) Peereniitaed Dy IROPIA, TOVERMON. .. 2200.2. 0 Vice es eee eee ee 84 Timber beetles. (See Ambrosia beetles and Corthylus columbianus. ) burning of that infested, to control insects which cause defects in living durability of that killed by insects......... LOS St Oe aOR 69 future supplies, insects in relation to reduction..................--.-- 67 EN gs Di UN eee eee ee eee 65 . 114 SOME INSECTS INJURIOUS TO FORESTS. Page. — Timber, infested, burning to control insects which cause defects in living wood. val | utilization for control of barkbeetles-2 22259. saan 74 newly felled, mjuries by msects, prevention. >. 22.22.2227... 5-- 2 see 79-80 | round, with bark on /inyjuries by -nmsects:_-: OSes. een eee 64-65 | standing, killed and damaged by insects, estimated loss........._.. 70-718 utilization, prompt, for prevention of injury from insects that infest | dyime and dead wood2.. 2225/22 2395 ae ee 78-79 — to control insects which cause defects in living wood.... 78 worm, chestnut (see also Lymexylon sericeum). | prevention of injury to living timber................ 785 | oak (see also Eupsalis minuta). prevention. of imjury to! lying) timbers. 48) 9 ee 78 || worms, injuries to-crudé forest, productss S920. 42 en 6 ee 64-65 | wood of dying and dead hardwood trees.......... 64 Timbers in dwellings, etc., Injuries by insects. . Lbs Le kh PU ee A eee 67 | Aeon 2). ee eee 83-84 Trap trees for control. of Dendroctonus/brenicomis ©: 32S! Se ee 28-30 Trees (see also Timber). utilizing varieties and races immune and resistant to insect attack... ... 79 Trogositidz, enemies of Monohammus titillator..........-....-. ta As Oe 53 | Turpentine beetle, black. (See Dendroctonus terebrans. ) red. (See Dendroctonus valens. ) beetles, injuries: to wood-of living pme:! 22)2222 72s eee 61-62 borer. (See Buprestis apricans.) Wagon stock, seasoned finished, injuries by insects, prevention ............-.- 82 powder-post beetles. ..........-.. 66 unseasoned, injuries by ambrosia beetles and roundheaded borers 65 insects, prevention’ =!) ! vis... Nemes 81 powder-post beetles.:. -..2. 22527222752. 66 Webb, J. L., paper, ‘‘The Southern Pine Sawyer ( Monohammus iitillator Fab.’’ 41-56 Western Pine-destroying Barkbeetle (Dendroctonus brevicomis Lee) Osis eee ee eee 17-30 Weevil, white pine. (See Pissodes strobi.) Wheelbarrows, injuries by powder-post beetles, prevention... -..-. eee "gs Wheels, finished seasoned, injuries by insects, prevention...........--..--- 82 Whitewashing against locust borer. 4.20 Py es ee 5, 6 Whitewood, injuries to wood of living trees ey Corthylus columbianus .....--- 61 Wood-boring larvee, injuries to utilized forest products...........-----..---- 67 — Woodpeckers, enemies of Dendroctonus brevicomis........-------- = Ge ee 27 Woodwork in new and old buildings, injuries by insects ....--..--...-.- Sats eee 67 PIEVENLION 2-9. oe 83-84 Aime echiorid. agaist termites... .'.5 2.5/3 a fee eee 84 WB) he " in he ie "a oe ee } Ro Wa , as PP Many : 7 - > ae Ce Panipes ieee te ‘ a Pes A eh, : in i ie A + 2 : : : 7 7 om J Bbc) ree wah p Ha ae es i i ok a) pile “an ; ay en bo ‘eh 7 th, ny ae ; Rake heb , on ae 7 %