S B 939 T68 EIMTD ENTOMOLOGY LIB- EL o. j: NEW MEXICO ,e of THE MECHANIC flgricultursl ExpspimEnt Slaliim BULLETIN NO. 7. /r/7^^, 1892 Scale-Insects in New Mexico LAS ('RUCKS. N. M. Kro (JRANDK RKPTJI'.MC\N 1892. The Agricultural Experiment Station. BOARD OF CONTROL: Board of Regents of the College. STATION STAFF. ' Hiram Hadley, A.M., Director. Aiiisworth E. Blount, A.M., Horticulturist and Agriculturist. Elmer O. Wooton, B.S., Botanist. C. H. Tyler Townseiid, Entomologist and Zoologist, Arthur Goss, B.S., A.C., Chemist, Harvey H. Griffin, B.S., First Assistant to Agriculturist and Horticulturist, Watt Gilmore, Assistant in Meteorology. SCALE-INSECTS IN NEW MEXICO. By ('. H. Tyler TowiiHeml. The question of scale-insects is a vital one to the fruit-grower. A considerable number of scales infest our fruit and shade trees, as well as our various native ornamental shrubs and plants; and in view of the recent recognition and quite rapid spread of the San Jose scale in the southern part of this territory, it becomes very desirable that accounts of our species be embodied in a bulletin for the benefit of the horticultural public. The people of southern California years ago set the example of arousing public opinion and securing valid legislation for the suppression of scale-insects and other pests, and it is gratifying to note that we have had in this territory, for one year, a similar law which compels fruit-own- ers to rid their orchards of all such pests. Being practically in close proximity to southern California, it is rather to be wondered at that we have not more of the fruit enemies which abound there, and which may at any time make their appearance within our limits. It is only by the greatest vigilance, and by measures of the utmost precaution on. the part of all concerned, that such a con- tingency can be prevented. The action which California has taken in the matter is commendable, and demonstrates the entire practica- bility of proper legislation on this point. We may well follow the example set us. and no pains should be spared, nor any feasible means neglected, to accomplish the suppression of such insects as the Smi Jose scale and kindred species. CLASSIFICATION OF SCALE-INSECTS. Iii order that the fruit-grower may be better enabled to recognize the various genera and species of scale-insects, a few paragraphs are devoted to their classification. SCALE INSKCTS They constitute the family known as the Coccidae, and belong to the Homoptera, which, is generally accepted by entomologists as a division of the order Hemiptera. Other familiar examples of the Homoptera are the plant-lice (Aphididae), the seventeen-year Cicada, the vine leaf -hopper, and the tree-hoppers. The cochineal and lac insects belong to the Coccidae. As there is considerable diversity of structure among the species of Coccidae, this family has been divided into five sub-families. One of these, the Bfachyscelinae, includes species which live in galls, and are wholly confined to Australia. The four remaining sub-fam- ilies may be ordinarily distinguished by the following table: 1. Scale composed partly of .molted skins, and partly of a secre- tion of the insect Scale composed of a secretion of the insect alone, or else absent; never in part composed of molted skins ........... . '2 2. Individuals usually fixed to plant on which they live ; the body of the female scale-like or rather globular, with segmen- tation absent or indistinct ................ L<>canhi(t<>. Individuals usually retaining the power of motion ; the body of female usually distinctly segmented .............. 3 3. Abdomen never terminating in two long caudal filaments .... ................................ Monophloebinae. Abdomen always terminating in two long caudal filaments . . ....................................... Cocci n( ic. Diaspinae. — Examples are the various species of Aspidiotus, to which belong the San Jose scale, the greedy scale, and the red scale of the orange in California. The genus Aspidiotus is distin- guished by the female scale being circular, or nearly so, with the exuviae either central or more or less marginal ; and the male scale somewhat elongated, with the exuvia more or less central. The fe- male scale may be distinguished by having two cast skins or exuviae beneath it, while the scale of the male has but one. Near the cen- ter of the scale, or between the center and the margin, will be seen IN NEW MEXICO. a small dot of a darker color than the rest of the scale. This marks the location of the cast skin or skins (exuviae) lying beneath the scale, and its position serves as a character for distinguishing differ- ent species and even genera of this sub-family. Lecaninae. — Examples are the various species of Lecanium, to which belong the black scale of California; the cottony maple- scale (Pnlvinaria innumerabilis Rathv. ) ; and the lac insect (Carter ia lacca Ker. ). In the genus Lecanium the female lays her eggs be- neath the scale, and secretes no cottony material. In the genus Pulvinaria the female secretes a mass of cottony material, in which the eggs are deposited. Monophloebinae.— Examples are the various species of Icerya, to which belongs the famous fluted scale, so destructive to the orange in California and originally brought from Australia ; also the mes- quite scale mentioned in this bulletin, and which will probably form a new genus. There are some gigantic species of this sub-family in Australia, some of them reaching, the length of nearly two inches ! Coccinae. — Examples are the cochineal insect (Coccus cadi L.); and the mealy bugs (Daotylopiu8\. GENERAL HABITS OF SCALE-INSECTS. The female scale-insect is always wingless, and does not undergo a complete metamorphosis. She fixes her beak in the bark, stem, leaf, or fruit while young, and becomes stationary (except the Mon- ophlochlnac and Coccinae), excreting and forming her scale as she grows. The male, however, of all scale-insects undergoes a complete metamorphosis, and is furnished in the adult state with a single pair of wings. The hind pair is wanting, but is represented by a pair of club-like appendages called halteres or balancers. Each of these appendages is furnished with a hooked bristle, which fits into a pocket on the margin of the wing of the same side, and doubtless serves to brace and strengthen the flight. The adult male has no organs for obtaining food, and takes no nourishment, his sole SCALE-INSECTS object in life being to impregnate the female, which is soon accom- plished. The mouth parts are lost during the metamorphosis, and what is strange enough, their place is supplied by a second pair of eyes ! As soon as the female scale-insect is fertilized, her body increases in size and becomes distended with eggs. These are deposited either beneath the scale, the body of the female meantime shrivel- ing until it remains but a shrunken skin beside the mass of eggs ; or a cottony sac is excreted by the female posteriorly to contain the eggs, and in which they hatch. When the young insects hatch, they may be seen with a lens crawling over the surface of the bark or leaf, preparatory to set- tling down and fixing their beaks therein (except the two sub-fam- ilies above mentioned, which do not become stationary). At this time, their bodies are very tender, but shortly after fixing themselves they begin to exude a scaly covering to serve as a protection to themselves. Scale-insects can spread from one orchard to another by the female crawling, or being carried by birds or the wind. She may even be carried by attaching herself to bees, and other insects. The larger species of scales more frequently spread by crawling ; but the smaller ones, such as the species of Aspidiotus, are no doubt often spread by the other means referred to. NO. i. THE SAN JOSE SCALE (Aspidio1n-x pemiriosus Conistock). Plate I. fig. 1. Scale of Female. — The female scale is flat and circular, with the exuviae central or nearly so. It is grayish in color, except the ex- uvial spot which varies from yellowish to blackish. In some spec- imens, according- to Comstock, the outer part of the scale is marked with radiating ridges. Diameter, 2 mm. (.08 inch). Female. — Body yellowish and nearly circular in outline, segmen- tation distinct. The last segment presents the following characters : Only two pairs of lobes visible, first pair converging at tip, notched IN NEW MEXICO. about midway their length on lateral margin, and often bearing a slight second marginal notch near tip. Second pair notched once on lateral margin. Scale of Male. — Smaller, quite different in appearance, being somewhat elongated instead of circular, blackish in color, and with the exuvia between the center and the anterior margin. ^99' — According to Comstock,the eggs are white ; but according to my own observation, they turn to an orange-yellow color in the spring. They hatch here about the first or second week in May. Food-plants. —Found here on apple, pear, plum, peach, quince, and rose. Attacks bark, leaves, and fruit. It has not yet occurred here on the apricot, but has been reported on this fruit in Califor- nia. It also infests the cherry; in fact, all the deciduous fruits are liable to its attacks. - This species is also known as the pernicious scale, and has been brought into New Mexico on young trees from California. It was first noticed as injurious in San Jose, whence the popular name. In California, it has proven to be the most destructive scale known on deciduous fruits, and also the most difficult to kill. It spreads rapidly. A reliable characteristic by which this scale may be recognized, when numerous, consists in the red discoloration of the bark occa- sioned by its attacks. The discoloration appears in reddish blotches over the bark, and when the latter is badly infested, extends through the bark and into the sapwood. It seems that the weather during the past winter has had some effect on the scales, many of them ap- pearing winter-killed. Parasites. — Three species of minute hymenopterous parasites of this scale are known in California. They are : Aphelinus myUlaspidis Le Baron (Plate I, fig. 4) : This is a little four- winged fly, the female of which is about 0.64 of a millimeter in length, with a wing expanse of 1.28 mm. Its general color is bright lemon-yellow; the base of the antennae or feelers is more or less dusky, the eyes blackish, the ocelli or simple eyes carmine, mandibles or SCALE-INSECTS jaws brown, and legs and wing- veins bright yellow. The wings are delicate and hyaline, but sometimes with a pale yellowish shade. The males average slightly smaller in size, and the club of anten- nae is a little more truncate at tip. With these exceptions they can hardly be distinguished from the female. (Drawn from Howard's description.) This species has been found parasitic on Mytilaspis pomorum (in 111., Mo., N. Y. ?, Calif.) ; Chionaspis pinifoliae (in Mo. ?, B.C.); Mytilaspis sp. on linden (D. C.) ; Diaspis carueli on juniper (D.C.); and Aspidiotus p&rniciosus. It was bred from the last scale by Mr. E. M. Ehrhorn, of California (see Insect Life, vol. iii, p. 487). In order to show the efficiency of this parasite, Mr Howard has compiled the following table from Dr. Le Baron's tables, showing that it alone destroyed more than 63 per cent, of the whole number of scales. . Whole number of scales collected from apple in different gardens 844 Number with round holes through which this parasite had escaped 289 Number having larvae of this parasite under them .... 244 Number destroyed by mites or unknown cause 254 Number of healthy and sound scales 57 Whole number 844 Aphelinus fusdpennis Howard : This is a very much smaller par- asite, only 0.06 of a millimeter in length, and with a wing expanse of 1.3 mm. Its general color is dull honey-yellow ; the antennae are smoky, blackish at tip ; eyes blackish, ocelli dark crimson ; a distinct transverse black band on occiput behind eyes, scutellum somewhat blackish at tip, abdomen with five dusky transverse lateral bands, legs and wing-veins honey-yellow. Front wings with an indefinite smoky patch below the stigma (spot near front border of wing), and another darker crescent-shaped streak near base of wing, convex on inside. (Drawn from Howard's description.) The male was un- known to Mr. Howard. This species is also widespread and quite a general feeder. It has been bred from Axpidiofus pcrnlclos/is (Cal.); Chionaspis euontjnn (Ma.); MyHlaspi* f a small pin; its eggs are laid singly in or upon the scales, and the larva or grub that hatches from this egg feeds upon the scale insect, and after com- pleting its growth arid passing through its preparatory stage, it gnaws a round hole through the scale and thus makes its escape. This parasite occurs in nearly all of the orange groves in the San Gabriel Valley, and in some of them its work is very noticeable. This is especially the case in the large. Chapman groves, in which I de- tected this parasite two years ago. During a visit to this grove a few days ago it was almost impossible to find any young red scales on the infested trees, while in other localities where this parasite does not occur, almost every leaf contains one or more of the young scales, this being the season of the year when they are most abundant. Mr. A. B. Chapman informs me that there is less red scale on his fruit this year than there has been since first his trees became so seriously in- fested with these pests. I have taken the necessary steps for introducing this par- asite into a locality where it did not previously exist, but it will be several months yet before the result of this experiment can be determined. This parasite destroys the red scale of the orange (Aspldiotus auranfii), and its yellow variety (A. citrinus) in California; and Mr. E. M. Ehrhorn has also bred it in California from the San Jose Scale (A. perniciosus). See Insect Life, vol. iii, p. 487. NO. n. THE WHITE PEAR SCALE (Aspidiotus rapax Comstock). Plate I, fig. 2. Scale of Female. — Very convex; exuviae between center and one side, and covered with secretion. Scale is gray, somewhat trans- 10 SCALE-INSECTS parent so that it appears yellowish when covering a living female; prominence covering exuviae is dark brown or black, usually with a central dot and concentric ring which are white. Ventral scale snowy white, usually entire. Diameter 1.5 mm. (0.06 inch). Female. — Body nearly circular in outline, bright yellow in color with more or less translucent blotches. The last segment presents the following characters: Groups of spinnerets wanting. Only one pair of well-developed lobes, the median, present. These are prominent, and each one is furnished with a notch on each side. Second and third pairs of lobes represented by minute pointed pro- jections of margin of body. Egg. — The eggs and newly hatched larvae are yellow. (From Comstock's description.) Food-plants. — This scale attacks a great number of plants, trees and shrubs. In California it has been found on olive, moun- tain laurel ( Umbellularia californica), almond, quince, fig, willow, eucalyptus, acacia, apple, pear, and others. In Florida, on Euony- mus japonicus. It has been found here on apple, pear, and peach. Like the preceding scale, it affects not only the bark of the trunk and limbs but the leaves and fruit as well. This species is also known as the greedy scale. It sometimes occurs in a locality in great numbers, when it becomes very destruct- ive, but as a rule it does not spread rapidly and is not to be com- pared with the San Jose scale. If, however, it is allowed to gain a good foothold, it will be troublesome to exterminate it, owing to the large number of plants upon which it subsists. Parasites. — Aphelinus fuscipennis Howard, mentioned under San Jose scale, is suspected by Mr. E. M. Ehrhorn of being a parasite of this species also. (See Insect Life, vol. iii, p. 487.) NO. in. THE CONVEX SCALE (Aspidiotus coiii'cxus Comstock). Plate I, fig. 3. This species very closely resembles A. rapcur. in the shape and color of its scale. It is only by a careful study and comparison of the two forms that it can be distinguished. A careful examination IN NEW MEXICO. 11 of their structure shows them to be specifically distinct. This species may be distinguished from A. rapax by the following char- acters of the last abdominal segment of the female : Four groups of spinnerets (none in A. rapax)', the superior lateral groups con- sist of about seven, and the inferior lateral groups of about four spinnerets. Food-plants. — Very common in California on the bark of the trunk and limbs of the native willows. It has been found in great numbers here on the bark of trunk and branches of our native cottoiiwood (Populus fremontii). The bark of the trunk of one tree was entirely covered. It has also been found here in great num- bers on the limbs and twigs of an ash (Fraxinus sp/). Parasites. — Great numbers of the scales on cottonwood showed minute holes from which some hymeiiopterous parasite had emerged. There were no living insects under such scales, showing that the parasite had done much good work in keeping the scales in check. Those on ash were also well parasitized. NO. iv. CHILOPSIS SCALE ( Aspidiotus n. sp. ?). This species bears some resemblance to Aspidiotus nerii Bouche, but is probably a new species. Professor Comstock, after an examination of specimens, writes that it is an Aspidiotus unknown to him, and probably undescribed. Further material is necessary before a description can be drawn up, therefore nothing more than a mere notice of its occurrence is given here. -__ . Food-plants. — This species was found plentifully infesting the leaves, mostly on the upper side, of a bush of Chilopsis saligna in the yard of Hon. A. L. Christy, of Las Cruces, who first called my attention to this scale. At date of examination, August 25, 1891, the scales were nearly all very small, and some orange-yellow young were seen outside. There were a few larger scales, containing eggs beneath them. The scales seemed to be confined to the leaves. NO. v. THE LOCUST SCALE (Lecanium robiniae Riley MS.). This is an entirely different scale, in appearance and size, from all of the preceding species, which belong to the genus Aspidiotus. 12 SCALE-INSECTS It is a brown, or reddish-brown scale, hemispherical in form, hard in texture, and varies from 3 to 5 mm. in breadth and 4 to (> mm. in length. Some of them are very dark brown in color. Be- neath this scale, as in the preceding species, is to be found either the soft insect or the eggs. The species has not been described, and I will not attempt to give other than the above brief description here. Professor Riley, who has seen specimens, has furnished the above manuscript name to be used in referring to the species. The short description and the food-plant will doubtless enable its recognition. Egg. — The eggs are pale reddish-pink in color, very small, and a great many are to be found under one scale. They were ob- served to be hatching May 22. Food-plants. — This scale has been found here only on im- ported trees of black locust (Rob In id jwinldcdcid), the branches and twigs of which it very plentifully infests. It is more or less unnoticeable on account of its color being much the same as that of the twigs upon which it occurs. Parasites. — No true parasites have been observed. A locust tree which was infested with the scale was found to be well stocked with the California Cooclnella oculata, and its ashy gray variety (C. abdominalis). These undoubtedly prey upon this and other scales. The variety seemed to predominate, and though all stages from eggs to adults were to be found May 22, the pupae were by far the most abundant. NO. VI. SOFT PEACH SCALE (LcCfllUHIK Sp.). A single specimen of a soft, brownish, more or less hemispher- ical scale-insect, about 5 mm. in length, was found April 11, 011 a branch of the peach. No others were found, and it is simply men- tioned here so it may be looked for by fruit-growers. We shall be glad to receive any specimens of it that may be found. Unlike all the preceding species, it is simply the bare, soft insect that must be looked for, as it apparently does not cover itself with a scale. IN NEW MEXICO. 13 NO. vii. THE YUCCA SCALE (LecanocUaspis yuccae Kiley MS.). This is a round, hemispherical, whitish scale, about 3 to 4 mm. in diameter, and of hard texture. The scale bears a median longi- tudinal carina or keel above, and is a little narrower than long. This species is also undescribed, and the above manuscript name was furnished by Professor Riley. It can be easily recognized when seen. Egg. — The eggs under dried scales are pale yellowish or whitish, and a considerable number occur under one scale. Food-plants, — This scale was found on leaves of DasyUrion tvheeleri, March 14, 1891, in the Organ mountains. It was later found on the large-leaved yuccas (probably Yucca macrocarpa), in the same mountains. In both plants, it infests the upper side of the leaves very plentifully, chiefly at and near their bases. These plants are highly ornamental, and the yuccas especially may be used to advantage on lawns. Therefore this scale becomes of con- siderable importance from an economic standpoint. Parasites. — Some of the scales which have been collected were found infested with a hymenopterous parasite, the black perfect in- sect of which could be seen inside the scale through a small round hole where it was about to emerge. NO. vin. THE LARREA SCALE (Signoretia sp. ? ). This scale is enclosed in a white felted or cottony covering. The insect itself is of a light reddish-brown, with the legs and antennae concolorous. The adult female has apparently 8 joints in the anten- nae, and the legs are present. The first antennal joint is short. The larva has only six antennal joints. The dimensions are as follows: Length of adult female, about 4 mm ; width, 2 mm. Length of felted sac, 5 to 6 mm; width, 2 to 2.5 mm. Egg.— The eggs are whitish in color and are enclosed in the end of the felted sac, behind the body of the female, the head of the female being usually more or less thrust through the anterior end of the sac. 14 SCALE-INSECTS Food-plants. — Found abundantly, May 13, on leaves of the creosote bush (Larrea mexicana) ; occasionally on the stems also. It is usually on the underside of the leaf, which is small and very nearly covered by the felted sac. Young specimens were also found this date, which were beginning to exude a sac, though the eggs found in the sacs of adult females were unhatched. It was ob- served that the whitish sacs were likely to escape notice among the young fruit of the Larrea, which was just setting and was cov- ered with a whitish, woolly pubescence. NO. ix. PALMER'S ICERYA (leery a palmer i Riley and Howard ). Plate II, figs. 1 and 2. This scale does not, so far as the writer is aware, occur in New Mexico. As will be seen, however, it becomes very desir- able to treat it here, since it is not unlikely that it may some day reach us. The adult stages are as yet unknown to science, and consequently can not be described. A description of the first and second larval stages will be found in Insect Life, vol. iii, pp. 104-5, but is too technical to be inserted here. The larvae are apparently reddish-yellow in color, but their cast skins are white. Food-plants. — This species was found by Dr. Edward Palmer July 30, 1887, on the Muscat of Alexandria grape, at San Jose de Guaymas, nine miles north of Guaymas proper, in Sonora, Mexico. The specimens found were only the younger stages, and were fixed alon^the main ribs of the leaf, principally on the under side. This would prove a new and most undesirable pest to our Muscat grapes if introduced here, and with the Santa Fe K. R. connections be- tween Guaymas and this territory it is by no means an impossibil- ity. All vines brought from Old Mexico should be most thoroughly overhauled before they are allowed to enter American territory. Parasites. — It is reported in Insect Life, 1. c., that the pupa- rium of a dipterous parasite, apparently of the family Phoridae, was plainly to be seen within one of the mounted larvae of the second stage. IN NEW MEXICO. 15 NO. X. COTTONY MESQUITE SCALE (n. gen. et n. Sp.). This is a large, soft scale, red or brick-red in color, and bear- ing a snow-white, more or less distinctly fluted, cotton-like, but compact egg-sac, which is attached to the postero- ventral portion of the insect, and is cylindrical in general form. The insect is en- tirely red, except the legs, antennae and proboscis, which are black ; and the egg-sac, which is white. Pinned specimens usually become reddish-yellow in color, while alcoholic specimens acquire a reddish-brown color. This scale also exudes, particularly around the edge of its body, a certain number of curled white cottony fila- ments, in addition to the egg-sac. The dimensions of the larger spec- imens collected in July, 1891, and May, 1892, are as follows: Length of body, 5 to 7 mm. ; anterior width of body, 2 to 3 mm. ; posterior width 4 to 5 mm. Length of egg-case, 5 to 6 mm. ; width, about 4 mm. Specimens collected June 8, 1892, measure 12 to 13 mm. in length, including egg-sac; sac measures 10 mm. This scale will probably form a new genus, according to Profes- sor Kiley who has examined specimens. It is nearly related to the Icerya of California, though somewhat more removed from it than the preceding species, which is a member of the same genus. Egg. — In color the eggs are orange-red. They were just be- ginning to hatch within the sacs, June 8. Food-plants. — Found on twigs and branches of mesquite (Prosopis juliflora) rather plentifully, July 28, 1891, many of them being at this time small. Found more sparingly, but in larger specimens, May 13 to 18, 1892; though two or three smaller ones without egg-sacs were also seen. A good number of large specimens were found June 8. This scale, it is possible, may some day take to certain cultivated plants, in which case it will prove a serious enemy. Parasites. — No true parasites have been found, but the two species of lady-birds, previously mentioned, frequented the mesquite branches where the scales were found, and doubtless prey upon them. In the same connection, it may be mentioned that two species of 16 SCALE-INSECTS ants, one of moderate size and the other very small, were seen at- tending these scale-insects, from which they obtain a honey-like ex- udation. The ants rather serve to protect the scales by warding off parasites and predaceous insects. This scale-insect was noticed to exude a drop of a clear honey-like fluid from the back posteriorly, upon which the ants fed. PARASITES AND OTHER ENEMIES OF SCALE-INSECTS. The insect enemies of scale-insects may be divided into two cate- gories : True parasites, which live internally in the host insect, and predaceous insects, which attack the scales externally and devour them bodily. The true parasites are very small members of the orders Hy- menoptera and Diptera, more particularly the former in the case of scale parasites. The hymenopterous parasites belong principally to the families Chalcididae and Prodofrupidae, two or three spe- cies of which have been more or less briefly described in the pre- ceding pages. The dipterous parasites belong principally to the Ochthiphilidae, a family of acalyptrate Muscidae, and perhaps to some other families of the same division. These parasites deposit their eggs in or upon the scale-insects, and the newly-hatched para- site lives within the body of its host until full grown, when it trans- forms and issues as a perfect insect. The chief predaceous insects, which are useful in destroying scales, are the following: Coccinellidae, or lady-birds; and certain predaceous lepidopterous larvae, belonging to the families Noc- iuidae, Phyvitidae, Tineidae, and Pyralidac. The predaceous ene- mies have proven of more value in California than the true para- sites, Of the Coccinellidae, or lady -birds, we have here two very efficient forms, which are mentioned in the preceding pages. They are Coccinella oculafa, and its ashy-gray variety ( C. abdomincdis, which looks like an entirely different species. The former is black with a yellow spot on each wing-cover, and the head and forward margin of thorax whitish. The variety is entirely creamy -jjray, with eight IN NEW MKXLCO. 17 spots normally on each whig-cover, seven on thorax with two fainter ones on front margin, while the eyes look like two black spots on the head. These lady-birds are California forms, and have not be- fore been reported from New Mexico. To the true dipterous parasites belongs the Lesfophonus icerijfu\ which was found parasitic on leery a in Australia, and was imported under Professor Eiley's direction into California. It has, however, been superseded in usefulness by the Vedalia, and some other coccinellid beetles which were imported later. REMEDIES FOR SCALE-INSECTS. Summer Washes. — As a summer wash for the San Jose scale, and other species of Aspidiotus infesting deciduous trees, the fol- lowing should be applied at various times after the young scales have hatched and are seen crawling on the bark : No. 1. Caustic soda (98 per cent.) . . 10 Ibs. Potash 10 Ibs. Tallow 40 Ibs. Eesin . . . 40 Ibs. Water to make 50 gals. The above forms a soap which will fill a barrel of 50 gallons measure, and will weigh about 450 to 500 pounds. It must be prepared as follows: First, dissolve the soda and potash in ten gallons of water, then place the whole in a 50-gallon barrel. Second, dissolve the tallow and resin together by heating it over a fire, add it to the soda and potash in the barrel, and stir well for about five minutes. Let it stand now for about two hours, when the barrel may be filled up with water, but the mixture must be well stirred as every bucket of water is added. It will be ready for use the following day, and should be applied warm in strength of one pound of soap to a gallon of water. This remedy is preferable for apples and pears, and was originally recommended, I believe, by Mr. Sol. Runyon, of Court- land, Cal. IS SCALE-INSECTS The following is recommended in California for same purpose, but for use on the peach: No. 2. Potash 14 Ibs. Caustic soda (98 percent.) .... 8 Ibs. Unslacked lime 5 Ibs. Fish oil, polar or seal 10 gals. Water to make 50 gals. Prepare as follows: First, dissolve thevsoda and potash in ten gallons of water, as with the preceding formula. Then slack the lime with two gallons of water in the 50-gallon barrel to be used, add the fish oil and stir well until the lime and oil form a thick batter. Now pour the soda and potash solution, boiling hot, into the barrel containing the batter, and stir well with a dasher for five minutes. Leave standing from 4 to 6 hours; after this length of time the barrel may be filled up with cold water, about two buckets full at a time, stirring well to prevent lumps. Use the following day and apply cold, in strength of one pound to a gallon of water. In dissolving this soap for use do not boil, but weigh amount to be used, place in barrel and pour hot water thereon, in propor- tion of one pailful to every one hundred pounds of material ; then stir briskly with a dasher until entirely dissolved. It can now be reduced with cold water as above directed, making as many gallons of wash as there were pounds of soap dissolved. After being well stirred, it is ready for use. This wash is also recommended in Cali- fornia for leery a on citrus trees and evergreens, and for Lccanhunx on deciduous or other trees. Another summer resin wash, recommended by Professor Riley for the red scale on the orange in California, differs from the above washes by containing no potash, and proportionally more than twice as much resin. It will doubtless be efficient for all species of Aspidioius, except the San Jose scale, but if used on deciduous trees it should be experimented with first to determine effect 011 the foliage. If the foliage is injured, more water can be added. The formula is as follows: IN NEW MEXICO. No. 3. Eesin 18 Ibs. Caustic soda (70 per cent.). . . 5 Ibs. Fish oil < 2J pints. Water to make 100 gals. It also differs from the preceding resin washes in the manner of preparation, and in being ready for application when mixed ac- cording to the above formula, instead of forming a soap to be dis- solved again in water. It is prepared as follows: Place all the ingredients in a large boiler with enough cold water to cover them. Boil until dissolved, occasionally 'stirring, and continue boiling for about an hour after the materials are dis- solved, employing sufficient heat to keep the mixture in a constant state of ebullition, and adding hot water when it is in danger of boil- ing over. When sufficiently boiled it will assimilate perfectly with water, which should then be added hot up to 50 gallons, slowly at first and stirring occasionally, and then cold water until a sufficient amount is added to make 100 gallons of the mixture. Before the water is added the preparation is of a pale yellow color, but after a adding it becomes dark brown. It must be strained through a fine wire seive, or a piece of Swiss muslin, before applying to the trees. Virtually the same remedy as the above, only in a little greater strength and with the addition of a little kerosene, is re- commended by the Calif oraia State Board of Horticulture for the red scale on orange, and other scales on evergreen trees ; while the same thing, only a little stronger and without the kerosene, is recom- mended for Icc-r'ijfi on the orange. The following is the Riley-Hubbard formula for the kerosene emulsion, which at proper strength will be found a very efficient remedy for scales: No. 4. Kerosene oil 2 gals. Common soap ^ 11). Water . . 1 gals. o Prepare by boiling the water and soap together until dissolved, and then pouring it, while boiling hot, into the kerosene. The SCALE-INSECTS. mixture must now be pumped through a force pump for about five minutes, directing the stream back into the pail, until it forms a perfect emulsion. As a summer wash for San Jose and other scales on apple, pear, etc., dilute nine times with cold water. For use on peach, dilute fifteen times. The following summer wash for San Jose scale on deciduous trees is recommended by the California State Board of Horti- culture : No. .5. Whale oil soap (80 per cent.). 20 Ibs. Sulphur 3 Ibs. Caustic soda (98 per cent.) .... 1 Ib. Commercial potash 1 Ib. Water to make 100 Ibs. Boil the sulphur, soda and potash in two gallons of water for one hour, or until thoroughly dissolved. Dissolve the soap by boiling it in water, then add to the other, mix and boil for a short time when it may be applied hot. Winter Washes. — In order to thoroughly destroy the San Jose scale, it will be necessary to use the following winter wash, which is much stronger than any of the preceding and must be ap- plied only when the tree is dormant. If applied in the growing season, it will cause the loss of both foliage and fruit. It is recom- mended by Professor Riley as giving the best results of all for use as a winter wash against this particular scale. It therefore needs- no further commendation : No. 0. Kesiii 30 Ibs. Caustic soda (70 per cent.). . . 1) Ibs. Fish oil 44 pints. Water to make 100 gals. Prepare by placing all the ingredients in a large boiler, and pouring over them about 20 gallons of water. Boil briskly for three hours, or until the compound is perfectly soluble in water. The boiler must now be slowly filled up with hot water, care being taken to stir well, until it makes 50 gallons of hot solution. This should NEW MEXICO. 21 be strained through a fine wire seive or a piece of muslin, when it can be diluted with an equal quantity of cold water as needed for spray- ing. It is recommended in California for Lecaniums, as well as San Jose scale, for winter use on deciduous trees. In the application of this wash a very fine spray is not essen- tial, as the object to be attained, that of thoroughly coating the tree with the compound, can be best accomplished by the use of a rather coarse spray, to be thrown on the tree with consid- erable force. The California State Board of Horticulture recommend the following as a winter wash against the San Jose and congeneric scales. It is claimed, and I believe with reason, that the addition of potash to the wash is necessary to prevent the dry atmosphere from exhausting the caustic properties of the soda. This is espec- ially important to us in New Mexico, as our atmosphere is much dryer than that of of California. If soda lye alone is sprayed on trees in sunny weather, it will often be found within an hour to have crystallized into solid carbonate of soda, and its action, so far as in- sects are concered, is at an end. If sprayed in moist weather, its action is prolonged. The addition of the potash, however, main- tains the corrosive action of the soda in the dryest atmosphere, by preventing the rapid evaporation and solidification which would otherwise put an end to it. Besides the potash ultimately reaches the soil, and acts as a fertilizer when needed. The above statements are on the authority of Professor Hilgard. No. 7. Solid concentrated American lye (80 per cent.). . 1 lb., or Powdered caustic soda (98 per cent.) 0.8 lb., or Powdered caustic soda (76 per cent.) 1 lb., or Powdered caustic soda (63 per cent.) 1£ Ibs., to Commercial potash (52 per cent.) 1 lb., and Water 2| gals. Simply dissolve the soda and potash in the water. First re- commended by Mr. M. Cooke. The following formula, recommended by Professor Hilgard, is 22 SCALE -INSECTS undoubtedly equally as good as the last, and costs one cent less per gallon. No. 8. Solid concentrated American lye (80 per cent.) . . 1 lb., or any one of the sodas in preceding formula, to Commercial potash (52 per cent. ) i lb. Water 2 gals. Simply dissolve. This is just a little more than one half the strength of potash that is given in the preceding formula. Comments. — The above 8 washes are given so as to allow some latitude in choice. They have been carefully selected, and will doubtless all prove more or less efficient. Those which will be of use for species of Aspidiotus and L&canium, are mentioned above. The last two formulas mentioned would, I believe, be especially ad- apted to our climate. For Lecanodiaspis, or other scales on Dasylirion and Yucca, I would recommend formula No. 6, to be applied at any time of the year. No. 4 diluted five times would also be of service, and would in all probability not affect the plants. As far as the scale on Larrea goes, it will probably not spread to any other plant, and doubtless the creosote bush is not valuable enough here to call for any protection. However, No. P> and No. 4, as above recommended, would be the proper remedies. For species of Icerya, and for cottony scale on mesquite, No. 3 is the formula which should be used, but the caution given above as to trying the wash first to get the strength which will not injure such foliage as grape or mesquite, must be heeded. No mention is made in this bulletin of the hydrocyanic acid gas method of destroying scale-insects, which is at the present time unnecessary in this territory. EXPLANATION OF PLATES. Plate I. ( All much enlarged. ) Fig. 1. — San Jose scale, Aspidiotus pprniciosits. last abdominal segment of female showing specific characters. IN NEW MEXICO. Fig. 2. — White pear scale. Aspidiotus rapax, last abdominal segment of female show- ing same. Fig. 3. — Convex scale, Aspidiotus convexus, last abdominal segment of female show- ing same. Fig. 4. — San Jose scale parasite, Aphelinus mytilaspidis. Plate II. Palmer's Icerya, leery a palmeri. Fig. 1. — a, newly hatched larva; 6, larva, second stage (both greatly enlarged — hairlines indicate natural size); c, antenna of 6 (still more enlarged). Fig. 2. — a, cast skins of larvae of second stage (much enlarged) ; 6, s ame clustered on ribs of grape leaf, on underside (natural size). Plate III. This plate shows a spraying outfit in operation, as used in orange groves in California against the fluted scale. NOTE. — The above plates were all received from the Agricultural Department in Washington, and appeared either in Insect Life or in the reports of the U. S. Entomologist. 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