J JLLETIN 442 JANUARY, 194^ MONTANA INSECT PESTS 1945 AND 1946 T/z/ery- F/z^sr Thirtieth Report of the State Entomologist by H. B. Mills, O. B. Hitchcock. and Ralph Schmiedeskamp MONTANA STATE CO AGRICULTURAL EXPERIMENT STATIO BOZEMAN, MONTANA Oct 3 1 2007 ^'ONTANA STATE L,BRARy HELENA. MONTANA 59620 Bozeman, Montana November 20, 1946 To His Excellency Gk>vernor Sam C. Ford State House Helena, Montana My Dear Sir: I take pleasure in presenting herewith the Thirty-first Report of the State Entomologist of Montana, covering the years 1945 and 1946. This report deals with cooperative large-scale insect control programs, the status of our more important or unusual insect control problems, and newly introduced pests. There have been some changes in the personnel of this office since the last report to you. Mr. O. B. Hitchcock, who was on military leave during the war period, returned to his duties on January 1, 1946, and Dr. J. A. Callenbach, who replaced him temporarily, is now on the staff of the Mon- tana State College and Agricultural Experiment Station. It has been possible to fill the position of State Apiarist, vacated through the resignation of Mr. J. F. Reinhardt, by the employment of Mr. Ralph Schmiedeskamp, a young man of considerable bee-keeping experience. Demands on this office continue to be heavy, and control work on the several important and wide^-pread insects requires much time. The work of the Apiculture Section has grown greatly, and law enforcement activities have subtracted from time available for disease control. The Apiculture Law was tested in District Court ai Hardin in December, 1945, and upheld by a unanimous jury verdict. If the duties of this office are to be properly performed in the next biennium, an increased budget is essential. Additional funds are needed for increases in salaries to offset higher living costs, for office help, and for seasonal assistance in the Apiculture Division. It was necessary, for finan- cial reasons, to terminate the duty of a deputy bee inspector at a critical time in 1946. The automotive equipment is old, the upkeep high, and the need great for replacement. Respectfully submitted, H.\RLOW B, IVDLLS State Entomologist Montana State Library 3 0864 1004 0549 "o MONTANA INSECT PESTS, 1945 AND 1946 Thirty-first Report of the State Entomologist H. B. Mills, O. B. Hitchcock, Ralph Schmiedeskamp* INTRODUCTION The constant and often insidious attack of insects on products which man desires and attempts to cultivate are so commonplace that they are accepted as a normal toll by most people most of the time. Different observers, using different methods of computation, have arrived at an estimate of 10 per cent as the usual expected loss, and often attempts at control are not employed unless obvious - losses are considerably in excess of this figure. The citizens of Montana, along with all others in the country, must pay this tax, whether or not they do it consciously. It is a func- tion of the State Entomologist's office to assist in reducing these losses by supervising, demonstrating, or otherwise assuming lead- ership in insect control work. Much of the damage caused by insects could be prevented by proper application of control measures at the right time. To make operations of this type effective, farm and ranch operators must obtain equipment to do the work quickly and efficiently, and they must also keep themselves informed as to the recommended prac- tices. Good operators spend large sums of money for equipment and materials and devote much time in discovering how to improve soil fertihty, breed better livestock, and generally develop their land and crops. In many cases, however, they have considered attacks by in- sects in the same category with weather, and therefore something that they could do little about. This attitude is erroneous, because at the present time satisfactory control measures have been worked out for most of the insects that cause heavy losses. New insecticides have been discovered that are more effective and easier to use than the old ones; new types of equipment have been invented, and im" provements on insect-control equipment have been made. The costs of material and equipment for insect control are not excessive in comparison to the savings that can be made. It is realized that much of the insect control work will come at a time when farmers and ranchers are extremely busy, but they do not neglect other farm practices and should not neglect insect con- trol. 'State Entomologist. Assistant State Entomologist, and State Apiarist, respectively. 4 MONTANA EXPERIMENT STATION BULLETIN 442 Farmers operating small units which would not justify the ex- tensive purchase of equipment can cooperate with their neighbors and purchase the machinery necessary to carry on effective insect control work. Farmers and ranchers should consider that insect control is as much a farm practice as cultivation, plant and livestock breed- ing, and many other operations that are necessary if their unit is to be productive. MAJOR INSECT CONTROL PROBLEMS GRASSHOPPER CONTROL, 1945-46 The grasshopper infestation in Montana has been increasing each year since 1942, when the State experienced the lightest in- festation in almost 10 years. During the period from 1938 to 1942 the dominant species in heavily infested areas of the State was, almost without exception, Melanoplus mexicanus. This was a result of the tremendous migra- tion of this species into the eastern part of the State during the fall of 1938, added to the heavy population already present. The carry- over and continued westward migration of this grasshopper made it the most important species for almost seven years. The present "build-up" is characterized by a gradual decrease of M. mexicanus, and an increase of Melanoplus hivittatus, M. jeraur-mhrum, and M. differentialis. The most noticeable increase of these species of grasshoppers is in the eastern part of the State, especially in the lower Yellowstone Valley, where they have re- placed M. mexicanus as the dominant species. The presence of M. differentialis is comparatively new in the State. Differential grasshoppers were first found in Dawson County in eastern Montana during the fall of 1932. It was believed that they flew in from South Dakota late in the fall." Their spread, since that time, has generally been in a southerly and westerly direction, almost to the Wyoming line in Big Horn County. In many areas in the eastern part of the State they have become the dominant species. During the last few years the standard bran bait has not been effective in controlling grasshoppers infesting alfalfa fields, field margins, and road right of ways where the vegetation remains green and succulent during most of the summer. As a result of in- adequate control methods, much grasshopper damage has occurred, especially in areas where seed alfalfa is grown. Experimental work has been carried on in an effort to find insecticides which will give *Mont. Agr. Exp. Sta. Bull. 269, p. 10. MONTANA INSECT PESTS 1945.-1946 5 satisfactory control of grasshoppers in alfalfa fields. A number of new insecticides, including 1068, Hercules 3956, benzine hexachlor- ide, and P. C. H. have been tried. Some of these have given very promising results and will be recommended for use in alfalfa fields to supplement present control methods. 1945 SEASON The grasshopper adult and egg surveys made in the fall of 1944 indicated that a severe outbreak was likely to occur in the eastern part of the State, especially along the Yellowstone valley. Light to threatening populations were expected in Big Horn, Yel- lowstone, Treasure, and Rosebud counties; in the northeastern comer as far west as Blaine County; in Hill, Liberty, Toole, Gla- cier, Pondera, Teton, Cascade, and Chouteau in the north central area; and in Ravalli, Missoula, Lake, Sanders, and Flathead coun- ties in the western part of the State. Cold weather in the spring delayed the egg hatch considerably, and it was late in June before the 'hoppers began to appear in large numbers. Hatching in some areas continued until late summer. Heavy weed growth along borrow pits, fence rows, and on idle lands furnished succulent feed during most of the season. Because of this, grasshopper movements into cultivated areas were delayed and the spreading of bait materially lessened. The most severe infestation developed in the lower Yellow- stone valley in Custer, Prairie, Dawson, and Richland counties and in Hill, Chouteau, Pondera, Cascade, and Teton counties, in the Tri- angle area. The dominant species in the Yellowstone valley was M. differentialis, with M. hivittatus second and M. mexicanus third. M. mexicanus was the dominant species in the Triangle area with M. hivittatus second in importance. Adult grasshoppers were first observed July 15, and egg laying started about August 15. Nymphal population in some areas was reduced by cold weath- er. Sarcophagid flies were instrumental in reducing M. differentialis population in Custer county. In the lower Yellowstone valley, M. differentialis and M. hivittatus were affected by fungus with some reduction in numbers resulting. Destruction of egg pods by blister beetle and carabid larvae was evident in the north central part of the State. In spite of the fact that there was a shortage of labor and equip- ment, the 1945 grasshopper control campaign was quite successful. Early season kills, especially in alfalfa, were not satisfactory, but late season baiting in all habitats was highly successful. Federally financed control work was carried on in Dawson, Prairie, Richland, Custer, and Chouteau counties. Crews paid by the Bureau of En- tomology and Plant Quarantine operated federally-owned trucks 6 MONTANA EXPERIMENT STATION BULLETIN 442 TABLE I.— CROP LOSSES FROM GRASSHOPPERS AND SAVINGS FROM CONTROL WORK IN DOLLARS County 1945 Losses Savings 1946 Losses Savings Big Horn 50,000 157,000 195,000 150,000 Blaine 31,760 3,180 Cascade 10,000 180,000 1,000 25,000 Chouteau 26,200 12,000 13,600 25,700 Custer 28,000 76,000 279,400 1,072,700 Dawson 4,050 21,700 1,650 45,400 Fallon 21,250 78,300 26,400 24,850 Fergus 16,000 5,500 Flathead 37,500 76,000 24,725 22,500 Garfield 1,025 2,420 Glacier 16,000 2,000 Golden Valley- Mussels'hell 12,000 168,400 9,000 40,000 Hill 145,000 432,375 Lake 4,400 3,500 320 Liberty 10,000 2,000 Missoula 300 1,300 Phillips 8,500 31,560 Pondera 3,000 926,011 700 436,300 Powder River 262,400 999,200 Prairie 37,000 22,000 32,250 8,750 Ravalli 1,000 500 Richland 16,020 20,625 5,500 750 Roosevelt 58,400 1,815 Rosebud 115.000 65,640 228,000 66,250 Saunders 4,050 1,500 Stillwater 1,500 3,500 80 5,400 Teton 12,000 95,000 120,000 130,500 Toole 5,750 11,509 Treasure 73,500 39,000 Valley 30,100 5,925 Yellowstone 59,625 103,000 23,500 55,000 Totals 718,395 2,493,351 1,207,160 3,193,100 MONTANA INSECT PESTS 1945-1946 7 and bait spreaders to treat 25,653 acres of railroad and highway- right of ways, ditch banks, and idle lands. This work was done in an effort to control heavy 'hopper populations in these habitats and prevent migration into cropland. In most counties farmer par- ticipation was stimulated and excellent cooperation was received. Approximately 4,172 acres, inaccessible to ground equipment, were baited by airplane. At present this type of control is too expensive to be practicable on a large-area basis. The estimated savings as a result of the control work were nearly 2!/^ million dollars, compared with approximately -''4 million dollars damage (table I) . One thousand seven hundred twenty- eight farmers spread 2,237 tons of bait over 343,264 acres of land (tables II and III) . The approximate cost of conducting the pro- gram was $216,753.34. Of this amount the State and counties con- tributed $23,000. the farmers $65,096.14, and the Bureau of Ento- mology and Plant Quarantine $128,657.20. It is estimated that for every dollar spent in grasshopper control work, $16.35 were saved. 1946 SEASON The 1945 egg survey indicated that a threatening infestation was likely to occur in the eastern third of the State with severe populations in the lower Yellowstone valley, extending from Miles City to the North Dakota line in Richland County. Light to threat- ening infestations were expected north of the Missouri River as far west as Glacier County, and in Lake, Sanders, Flathead, and Missoula counties. The light to threatening infestation expected north of the Mis- souri River failed to develop. In the western part of the State, only Lake and Flathead counties had infestations of economic import- ance. The severe outbreak in the eastern counties extended much farther south and covered a larger area than was anticipated. The infestation as a whole covered a considerably smaller area, but 'hopper populations were more severe than the egg survey indicat- ed. The counties having the most severe infestations were Big Horn, Treasure, Rosebud, Custer, Powder River, and Prairie in the east; Cascade, Pondera, Chouteau, Teton, Toole, and Glacier in the Triangle area; and Lake and Flathead in the western part of the State. The dominant species for the State were Melanoplus mexican- us, M. dijferentialis, M. hivittatus, and M. femur-ruhrum, in the or- der named. The distribution of these species was spotted with each being dominant in one or more areas. There was a marked increase of M. femur-ruhrum in the eastern part of the State. The impor- tance of this species has been significant this season. MONTANA EXPERIMENT STATION BULLETIN 442 TABLE II. SUMMARY OF BAIT USAGE 1945 1946 No. No. Tons farmers Tons farmers County bait using Acres bait using Acres dry wt. bait baited dry wt. bait baited Big Horn 158 70 7,600 198 103 19,500 Blaine 8 13 1,648 3 4 178 Cascade 117 85 22,880 20 38 2.200 Chouteau 393 140 68,000 35 50 17.200 Custer 319 221 63,820 298 423 45,430 Dawson 192 245 8,000 36 90 1,385 Fallon 14 14 2,133 18 42 3,388 Fergus 8 25 1,300 Flathead 32 188 11,500 19 161 2,900 Garfield 5 11 800 Glacier 4 5 800 Golden Valley- Mussels'hell 13 7 7.778 5 20 5,400 Hill 211 170 41,750 Lake 20 59 3,795 1 13 315 Liberty 2 3 300 Missoula 4 41 320 Phillips 9 32 1,500 4 4 789 Pondera 104 57 17,788 127 71 24,023 Powder River 311 287 52,800 Prairie 104 93 14,095 37 29 4,072 Ravalli 1 43 152 Richland 304 26 28.238 4 50 70 Roosevelt 2 4 505 Rosebud 7 69 4,844 313 209 29.512 Sanders 16 10 1.190 1 2 100 Stillwater 2 9 830 12 10 370 Teton 101 50 13,000 98 110 10.000 Toole 13 16 1,360 Treasure 57 24 7,500 Valley 21 11 1,150 Yellowstone 71 50 18,:^>50 65 101 6,350 Totals 2,237 1,728 343,264 1.680 l.S 235.622 MONTANA INSECT PESTS 1945-1946 TABLE III— SUMMARY OF GRASSHOPPER CONTROL PROGRAM tions 1945 1946 Number of mixing sta' 32 24 Counties actively engi aged 27 23 Farmers using bait 1,728 1,868 Dry bait used 2,237 1,680 Acres baited 343,264 235,622 Estimated loss $718,395 $1 ,207,160 Estimated savings $2,493,351 $3 ,193,100 Cool weather in the spring of 1946 delayed and caused an ir- regular hatch of grasshopper eggs. In the late summer, adults and first and second instar nymphs v^ere observed in the same areas. The first grasshopper nymphs were observed May 15. The hatch was about 50 per cent complete by June 7, and on June 14 approximately 75 per cent of the eggs had hatched. Hatching was not completed until August 9. By July 22 it is estimated that less than 5 per cent of the 'hoppers had reached the adult stage. Egg deposition was noticed for the first time about August 15. Light, milling grasshopper flights of a local nature occurred in the eastern part of the State almost daily during the first part of August, re- sulting in increased field populations and general dispersal from right of ways, fence rows, ditch banks, etc. Fungus or bacterial diseases were responsible for population decreases of 5 per cent to 10 per cent in some localities in the eastern part of the State and the Triangle area. Sarcophagid flies were not so much in evidence as in previous years. It is estimated that ap- proximately 10 per cent of the egg pods were parasitized by blister beetle, carabid, and bee fly larvae this fall. Cold, wet weather this fall was not favorable for egg laying, and it is felt that this may bring about a reduction in populations in some areas next year. In spite of the fact that weather conditions were unfavorable for control work during the early and late parts of the season, the program was quite successful. The results of baiting in alfalfa fields, along ditch banks, right of ways, fence rows, etc., where there was rank vegetative growth, were disappointing. With the exception of alfalfa, farmers were able to protect their crops from grasshopper damage by baiting. Although the amount of bait spread this year was 557 tons less than was put out last year, the estimated crop saving in 1946 10 MONTANA EXPERIMENT STATION BULLETIN 442 was almost $700,000 greater than in 1945. If weather conditions had been more favorable for fall baiting, the tons of bait used would surely have exceeded last year's figure. A federally financed road side baiting campaign was conducted again this year. In general the results were not good and the work was hampered by unfavorable weather conditions. Federally paid crews and equipment operated in Custer, Rosebud, Chouteau, Pon- dera, and Teton counties, spreading 80 tons of bait on 10,243 acres along highway and railroad right of ways. It is estimated that approximately $3,193,000 were saved as a result of the control work and that the loss from grasshopper dam- age was $1,207,160. In the 23 counties that were actively engaged in the campaign, 1,868 farmers treated 235,662 acres of land using 1,680 tons of bait (tables II and III). GRASSHOPPER OUTLOOK FOR 19 4 7 SEVERE VERY SEVERE i I THREATENING Figure 1. Results of the autumn, 1946, grasshopper egg survey, indicating areas where crop damage is likely to occur in 1947. GRASSHOPPER OUTLOOK FOR 1947 The grasshopper egg survey made in the fall of 1946 indicates that threatening to very severe infestations are likely to occur in the Triangle area including parts of Glacier, Toole, Pondera, Lib- erty, Teton, Chouteau, and Cascade counties, as well as in Fergus County; the highest egg counts that have been made in the State in MONTANA INSECT PESTS 1945-1946 11 several years were reported from Glacier, Toole, Pondera, Liberty, and Chouteau. In the eastern part of the State the infested area appears to be considerably reduced. Light to severe infestations are expected in Richland, Dawson, McCone, Prairie, Custer, Rose- bud, Treasure, Powder River, Carter, Big Horn, Yellowstone, and Stillwater counties, with the heaviest populations being in Custer, Powder River, Rosebud, Treasure, and Big Horn. Although weather conditions prevented a detailed survey in the western part of the State, it appears that light to threatening infestations are likely to occur in eastern Sanders, northern Lake, and southwestern Flathead counties. Indications are that the infested area will not be so extensive, in the State as a whole, as it was in 1946 and for several years previous to 1946. However, populations will possibly be more con- centrated and heavier than in the last five years, and serious local damage may result. OTHER IMPORTANT INSECT PESTS, 1945-46 MORMON CRICKETT {Anahrus simplex) . — Populations of this insect during the past two years have been light and not of econ- omic importance and control work has not been necessary. Severe outbreaks of Mormon crickets have occurred in Nevada, Idaho, Washington, and Oregon this year, and it was feared that heavy infestations in these states might be an indication that a "build-up" could be expected in Montana. A survey was made in areas which were heavily infested from 1934 to 1942. This survey included sections of the following counties: Big Horn, Yellowstone, Carbon, Custer, Rosebud, Sanders, Lake, Chouteau, Cascade, Fer- gus, and Judith Basin. Widely scattered crickets were found in these areas, but no bands or heavy populations were observed. It appears that there has been a slight increase in the number this year, especially in the areas in Big Horn, Rosebud, and Powder River counties. All potential cricket areas in the State will be watched closely in an effort to control small incipient outbreaks before they be- come severe and migrations into crops occur. FIELD CRICI^ET (Gryllus assimiUs) . — An outbreak of field crickets was observed causing considerable damage to seed alfalfa in Big Horn County in the vicinity of Hardin. The fields which were inspected had an estimated average of 20 crickets to the square yard. The insects were feeding on all parts of the plants and were especially injurious to the seed pods and blossoms. Egg deposition was extremely heavy and it is likely that a severe infestation will occur again next year. 12 MONTAJSTA EXPERIMENT STATION BUULETIN 442 A small area was dusted with 5 per cent DDT dust in an effort to determine the effect of this insecticide upon crickets. Excellent results were obtained, and good kills also were observed on an ad- jacent area covered by dust drifting from the test plot. The drifting dust was effective for a distance of over 200 yards. EARWIGS (Forficula a^iricularia) . — Since earwigs were first reported in Sanders County in 1939', the infestation has gradually spread to other counties and the economic importance of these in- sects as garden pests and household nuisances has greatly increased. In 1945 and 1946, they were reported doing considerable damage to gardens and truck crops in Sanders, Lake, and Flathead coun- ties. In 1946 the most severe infestation of earwigs ever to occur in the State was recorded in Flathead County in the vicinity of Columbia Falls. The damage caused by the insects to gardens in this area was quite extensive. ALFALFA WEEVIL (Hyperia postica) . — The alfalfa weevil, which has been discussed in previous reports*, was abundant and highly injurious to alfalfa in its area of infestation during both years of the past biennium. This represents the first evident injury from this pest in the State. On July 6, 1945, a survey was made of the western part of the area. The alfalfa weevil was found to be abundant and injurious near Silesia, with the first cutting of hay reduced by 50 per cent in some spots. This weevil was also abundant at Joliet and consider- able damage was evident. Light injury was apparent on the Carbon- Stillwater county line between Boyd and Columbus, and five miles southeast of Columbus moderate numbers and some damage were observed. The westernmost larvae were swept from an alfalfa field one-half mile west of the viaduct on Highway No. 10 between Columbus and Reed Point. Other observations and reports indicat- ed that the alfalfa v/eevil was present throughout Carbon, southern Yellowstone, southern Treasure, Big Horn, southern Rosebud, and into Powder River counties, and injury was substantial through the central part of this area. In 1946 Montana experienced its most severe alfalfa weevil outbreak. Extremely heavy infestations of this insect occurred in Csrbon. Stillwater, Yellowstone, Big Horn, Treasure, Rosebud, Powder River, and Custer counties, and the hay and alfalfa seed crop in these counties was severely damaged by this insect. Since the alfalfa weevil is comparatively new to most of the area, many farmers were not aware of its presence. They blamed weather *Mont. Agr. Exp. Sta. Bull. 384, p. 25. *Mont. Agr. Exp. Sta. Bulls. 384, p. 23, 1941, and 425, pp. 21-22, 1945. MONTANA INSECT PESTS 1945-1946 13 conditions for the poor growth and sickly appearance of their fields, because they did not realize that the weevil was causing the dam- age. Although the activities of this insect are greatest during the growth of the first cutting, many fields were so badly damaged that second and third hay crops as well as seed production were considerably reduced. Information concerning the alfalfa weevil and its control was published in local newspapers and distributed through county agents' offices in an effort to reach as many farmers as possible. The majority of operators were unable to do control work, because they did not have spraying or dusting machines, and dealers were not able to obtain such equipment. The present indications are that sprayers and dusters will be on the market next spring and will be available in sufficient numbers so that farmers wishing to do con- trol work can obtain equipment. A bulletin on the alfalfa weevil and its control has been pre- pared and will be distributed through the county extension agents' offices before spring. Unless conditions are unfavorable for the weevil, it is expected that the infestations in 1947 will be as severe as last year and that the area affected will be larger. CLO\nER ROOT CURCULio (Sitona spp.) .—This small, grey broad-nosed weevil was found causing injury to alfalfa in the Yel- lowstone Valley in 1946. Larvae and pupae were removed from typically injured roots collected near Worden, Montana, by County Agent W. H. Jones, on June 27. Injured fields were seen in Still- water and Yellowstone counties. Clover root curculios attack several legumes including alfalfa, the common clovers, cowpeas, soy beans, and possibly others. Plants attacked by these pests wilt and may die. Injury is most obvious during periods of dry weather. Roots of affected plants will be found to have the surfaces scored and furrowed, almost to the extent cf complete girdling. This injury is caused by the grubs which are pale, legless, brown-headed, and about one-sixth of an inch in length. Clover root curculios usually spend the winter as small grubs and feed on roots in the spring. The adult beetles feed on the leaves in late spring and early summer. An effective control for the clover root curculio has not as yet been dev:sed. Late fall or early spring plowing has been found to assist, and rotation with grasses or cultivated crops will drive the pests from the fields. Treatment, during the period of adult feed- mg, with some of the newer insecticides may be of value, but ex- perimental data are lacking. 14 MONTANA EXPERIMENT STATION BULLETIN 442 PEA WEEVIL (Bruchus pisorum). — This pest was extremely abundant in the Billings area in 1945, and considerable loss of peas resulted. In 1946 it was of minor importance. Examination of past records of its occurrence in Montana, and an extensive survey in 1941 led to the conclusion that the State was marginal as far as extensive outbreaks are concerned. ' The pea weevil appears to fall in that group of insects which may fluctuate considerably in num- bers from year to year, and, at present, methods of predicting severity of infestation have not been developed. ASPARAGUS BEETLE (Criocerus asparagi) . — Montana has been remarkably free from many of the important garden pests which plague truck growers in other parts of the country. Such insects as the Mexican bean beetle and the squash bug do not occur in the State, and others, such as cucumber beetles and the tomato horn worm, are uncommon. The asparagus beetle was unreported in Montana until the spring of 1946, when Mr. H. A. Johnson of Poison submitted speci- mens on May 29. A survey of the area on June 6 disclosed a distri- bution involving plantings along the southeast portion of Flathead Lake from a point two miles east of Poison and north to Findley Point. It is possible that the beetle occurs farther north, but the surve\- extended only to the Point. Probably the infestation started from imported crowns plant- ed somewhere within the presently infested area previous to 1946, and there is no neason to believe that the infestation will remain within its present boundaries. The asparagus beetle attacks only asparagus as far as is known. It is a European species, first appearing on the east coast about eighty-five years ago. It has spread throughout the East and occurs in some western states. The adult beetle is a pretty insect, about one-eighth of an inch in length. The wing covers are shiny bluish- black marked with cream colored spots, and the thorax is red. The thorax is narrower than the head or the body, giving it a "narrow necked" appearance. Adults hibernate during the cold months wherever they can find proper protection, coming out in the spring to deposit their eggs on asparagus growth. The eggs are dull slate-grey, and con- spicuouslv placed at right angles to the stem. Within a%veek they hatch into small fleshy, grey larvae, which commence immediately to feed on the growing t^ps. When fully developed, and about one- third of an inch in length, they drop to the ground to pupate. Adults emerge from the soil in approximately a week to lav eggs for a new generation. They fly readily and' may infest plantings close «Mont. Agr. Exp. Sta. Bull. 408, pp. 22-23 and Mont. Ext. Serv. Cir. A-30. MONTANA INSECT PESTS 1945-1946 15 by. There may be as many as five generations per year, the last group of adults going into hibernation. Asparagus beds which are not being cut for food can be spray- ed with lead arsenate at the rate of 3 pounds to 50 gallons, or 1 ounce to 1 gallon, of water. Soap should be added in a quantity equal to that of the lead arsenate used. Dusting has been recom- mended to replace spraying, using 1 part lead arsenate to 8 or 10 parts of lime. Asparagus being cut for food should not be treated with an arsenical. Recommended treatment during this period consists of dusting with a 5 per cent rotenone dust or spraying with a rotenone extract. WHEAT STEM SAWFLY (Cephus cinctus) . — This insect re- mains the primary wheat pest in Montana. A conservative estimate of losses sustained in the State in 1945 is four million bushels. The experiments on control of this pest have been carried out in co- operation with the Department of Agronomy and Soils, and the Ex- tension Service at Montana State College. The greatest hope for immediate relief lies in the new wheat, Rescue, which is apparent- ly sawfh^ resistant. It was developed at the Experiment Station at Swift Current. Saskatchewan. From a start of two bushels, re- ceived from the Canadian workers in 1944, there is an estimated seed stock of 60,000 bushels in Montana at the present time. It will probably be 1948 before any appreciable amount of this variety reaches commercial channels. Figure 2. Approximate extent of Hessian fly infested area, 1945. 16 MONTAJNTA EXPERIMENT STATION BULLETIN 442 HESSIAN FLY (Phytophaga destructor) . — The Hessian fly continued to be a severe spring wheat pest in parts of eastern Mon- tana during 1945, when weather conditions again favored its in- crease and depredations. Figure 2 shows the area most seriously in- fested. Damage in some fields amounted to total loss of the crop and lasses of 50 per cent or more were common. Because of the serious nature of the infestation, some cultural controls were attempted by the farmer. Attempts were also made by this office to check on reported resistance of certain wheat varieties to Hessian fly attack, but data collected were not conclu- sive. Plans were made to test these varieties experimentally in 1946, but the 1946 infestation failed to materialize, possibly because of the cool, dry spring. No infestations of economic importance were found during the entire season, and, after two years of ob- vious damage to wheat crops, the Hessian fly has apparently re- verted to its position as a pest of relatively little importance to Montana. FALSE CHINCH BUG (Nysius ericae) . — This insect is com- mon and sometimes abundant in Montana, but its injury to crops is usually not sufficiently intense to be noticed. However, in the sum- mer of 1945 it migrated in large numbers into a mustard field north of Valier in Pondera County where it attacked the plants near the ground line, completely destroying most of an 80 acre field. Control measures against this pest have not been developed. ARMY CUTWORM (Chorizagrotis auxiliaris) . — These early sea- son pests were in evidence in Montana during both of the past two years. Their feeding on winter wheat was conspicuous, and con- siderable damage was done. During the spring of 1945 an area in the central part of the State comprising parts or all of Chouteau, Judith Basin, Fergus, Petroleum, Wheatland, Golden Valley, Musselshell. Treasure, Yel- lowstone, Stillwater, Carbon, and Big Horn counties were infested. It was estimated that more than 300,000 acres were affected and approximatey 1,000 acres were completely destroyed. In 1946 the infestation appeared in the southeast corner of the State, involving the Powder River-Fallon county area. The army cutworm readily takes the sodium fluosilicate grass- hopper bait, and control has been successful with this material. A considerable amount of bait was used in stopping these pests in both years. MONTANA INSECT PESTS 1945-1946 • 17 WHEAT TIGER MOTH (Collarctia hlakei) . — This pest record- ed in the Thirtieth Report of the State Entomologist' as attacking wheat, was reported again in 1946. Specimens, collected south of Gildford in Hill County, were received from County Agent R. F. Rasmusson on April 9. According to the information received, the larvae were first noted on range land about one-half mile from a wheat field. In a few days they had reached the field and had worked several rods into it, eating all of the wheat as they pro- gressed. There was no further report on this infestation, although information was solicited, and there is a possibility that the field recovered as did the one observed in 1944 in Chouteau County. It appears, from scattered evidence, that the larvae overwinter on rangeland, moving early in the spring to wheat fields. Injury, although obvious early in the season, appears to be short-lived, and with good growing conditions may be overcome by later growth. Up to the present time, infestations have been spotted and not widespread. CATTLE GRUBS (Hypoderma lineatum and H. hovis) . — In or- der to best adapt control measures for these pests of cattle to Mon- tana conditions, observations on their biology were begun in 1943 and carried through to the spring of 1946. These studies have as- sisted in clarifying unknown points in the life cycles of the grubs, and have allowed the establishment of a schedule of treatments for cattle in the State. Although not so complete as would be desir- able, these data are brought together in Montana Agricultural Experiment Station Bulletin 437. MALARIA MOSQUITOES (Anopheles spp.) . — The return to Montana of many members of the armed forces suffering from malaria, contracted in various parts of the world, has brought to the fore the need of more information on the distribution of ano- pheline mosquitoes in the State. The return of infected war vet- erans is illustrated by the fact that in June 1946, 26 male students at Montana State University and 22 at Montana State College apparently harbored malaria parasites. As there was only scattered information on the State distribu- tion of anophelines, an extensive survey was carried on in western Montana in April and May 1946, by Dr. D. J. Pletsch of the Mon- tana Agricultural Experiment Station. The survey indicated that this genus of mosquitoes was more generally distributed in the surveyed area than was previously supposed. Counties visited were Deer Lodge, Flathead, Gallatin, Granite, Jefferson, Lake, Lincoln, Mineral, Missoula, Powell, Ravalli, and Sanders. Ten of these counties gave positive collections either of larval or adult anophelines. Larvae were found in 11 of 47 larval habitats. Ano- "Mont. Agr. Exp. Sta. Bull. 425, p. 22. 18 MONTANA EXPERIMENT STATION BULLETIN 442 pheles maculipennis, known as a possible transmitter of malarial parasites, proved the more common form. New records were also obtained for Anopheles punctipennis. a form widely distributed in North America. This species, previously known from a single collection at Lolo, was found in three additional localities. While carriers of the disease and the mosquito transmitters certainly occur in the same areas in Montana, widespread out- breaks among persons exposed to the disease within the State are not likely to occur. The possibility of occasional cases of local- ly contracted malaria cannot be overlooked, however. The problem is dealt with in more detail in an article by Dr. Pletsch in the Journal-Lancet.' BIENNIAL REPORT OF THE MONTANA STATE APIARIST, 1945-46 A study of bee registrations for Montana indicated that there has been a steadv increase in the bee population of the State for the past few years: in 1941 there were about 36,000 colonies, while in 1946 nearly 60,000 were being operated. This increase is a result of two factors. Because of high orices of honey and beeswax (1) new beekeepers have established them- selves, and (2) local producers have increased the numbers of colonies under their operation. With the increase in the bee pop- ulation in Montana there has been a marked decrease in the honey production per colony, as the following table demonstrates: Year Colonies operated Average production per colony 1941 36,000 128 lbs. 1942 37.000 128 lbs. 1943 41,000 102 lbs. 1944 44,000 101 lbs. 1945 56.000 76 lbs. 1946 58.000 The final crop reports for 1946 are not available at the pres- ent time, but for the most part yields appear to be poorer than in 1945. This decrease is easily understood. While only a few new terri- tories were brought under production, there were over 20.000 more colonies operated, and these additional colonies took 1,200,000 pounds of honey for their winter's feed alone and probably three times that much for summer consumption. ■Vol. H4 (9): 289. Sept. 1946. MONTANA INSECT PESTS 1945-1946 19 DISEASE CONTROL Disease control is the prime purpose of the bee inspection service. However, this inspection cannot be conducted as in many other states, because funds and personnel are limited. Hence, it has been necessary to set the limited objective of eliminating, as far as possible, disease sources which are not properly controlled. Our worst and most common bee disease is American foulbrood. Amateur and non-professional operators often know little or nothing about this disease. Therefore, the principal problem is to control sources of American foulbrood in hives managed by these two groups of operators. It must be kept in mind that the inspection records reflect primarily the disease condition among bees operated by amateur beekeepers. Since there are neither personnel nor funds available to allow the inspection of more than a small portion of the com- mercial or professionally operated bees, it is necessary that most of these operators control disease in their own apiaries. In a lim- ited way, the inspection of commercial apiaries has been very necessary. In most cases, though, professional apiarists have seen the necessity of taking care of their own problem and have clean- ed up and salvaged infected products and equipment as efficiently as possible. While box hives, or hives with cross combs, were at one time great potential sources of disease in the State, at the present time there are few beekeepers who use this tvpe of equipment. As a whole, the disease problem in Montana looks much brighter than in 1941 when inspection was reinstated after eight years' cessa- tion. In 1941, 26 per cent of all the colonies inspected in Montana were found to have American foulbrood. By 1946, this figure had been cut to 4.8 per cent. However, this achievement could never have been reached without the splendid help of the commercial beekeepers. LAW ENFORCEMENT The high prices paid for honey and beeswax during World War II and the good honey crops produced in Montana in the early years of this decade painted a pretty picture for beekeepers outside Montana who had been having poor crops for several years because of overstocked territories. With Montana as an ap- parent land of plenty, beekeepers desired to import thousands of colonies from outside areas. Some of these apiarists complied with Montana laws, and some attempted to move bees into the State in defiance of them. Checking on reported illegal movement of bees in the past two years has taken a great deal of the inspec- tor's time which might have been spent controlling disease infec- 20 MONTANA EXPERIMENT STATION BULLETIN 442 tions in need of attention. The fact that the productive territories of Montana are over- stocked has been an aid in bringing these violators to justice, for local commercial beekeepers have given the inspection service cooperation and support in coping with this problem. Law enforce- ment officers of the different counties have been very cooperative in helping to bring offenders to justice. VALUE OF HONEY BEES TO THE STATE Montana produces nearly one million dollars' worth of honey and beeswax yearly. Since sugar is still controlled, honey is in great demand to help ease the sweet shortage. Beeswax is a valu- able by-product of the honey industry, in war for the manufacture of munitions, and in peace for the manufacture of polishes, greas- es, waxes, dental impressions, and many other items which add to the health and comfort of mankind. However, honey and wax are but a part of the value of honey bees. Their most important role is played in the pollination of fruit and seed crops. The value of bees for this purpose is greater than is commonly recognized in Montana and should be encouraged wherever bee-pollinated crops are grown in the State. MONTANA INSEXJT PESTS 1945-1946 21 TABLE IV —RESULTS OF BEE INSPECTION DURING THE PAST BIENNIUM 1945 County No. inspections No. A-F.B. %A.F.B. Big Horn 250 Carbon 590 Cascade 140 Custer 63 Dawson 22 Flathead 317 Gallatin 2097 Jefferson 64 Lake 1254 Lewis and Clark 126 Madison 331 Missoula 116 Pondera 16 Rosebud 238 Sanders 185 Sweet Grass 18 Teton 698 Valley 102 YeUowstone 1226 Totals 7853 48 24 1 8 0 167 37 4 146 108 134 9 0 12 4 1 11 22 127 736 1946 19.2 12.6 .7 12.7 0 52.7 1.7 6.0 11.6 85.7 40.4 7.7 0 5.0 2.1 5.5 1.5 30.0 10.4 9.3 Big Horn 98 Blaine 252 Carbon 53 Cascade 6 Fergus 74 Flathead 230 Gallatin 2154 Judith Basin 28 Jefferson 70 Lake 283 Lewis and Clark 161 Madison 1390 Missoula 58 Phillips 122 Pondera 111 Ravalli 465 Sanders 69 Teton 267 Valley 5 Yellowstone 328 Totals 6223 1 4 37 0 14 11 8 5 2 17 10 115 4 0 3 53 0 4 1 12 "3or 1.0 1.2 69.8 0 18.9 4.8 .4 17.7 2.8 6.0 6.2 8.2 6.9 0 2.7 11.4 0 1.2 20.0 3.7 ~0" 22 MONTANA EXPERIMENT STATION BULLETIN 442 INDEX Page INTRODUCTION 3 MAJOR INSECT CONTROL PROBLEMS 4 Grasshopper Ccmtrol, 1945-46 4 1945 Season : 5 . 1946 Season 7 Grasshopper Outlook for 1947 10 OTHER IMPORTANT INSECT PESTS, 1945-46 .U Mormon Cricket 11 Field Cricket 11 Earwigs 12 Alfalfa Weevil 12 Clover Root Curculio 13 Pea Weevil 14 Asparagus Beetle 14 Wheat Stem Sawfly 15 Hessian Fly .. 16 False Chinch Bug 16 Army Cutworm , 16 Wheat Tiger Moth 17 Cattle Grubs 17 Malaria Mosquitoes 17 BIENNIAL REPORT OF THE MONTANA STATE APIARIST, 1945-46 ^ 18 Disease Control 19 Law Enforcement -19 Value of Honey Bees to the State -20