TWENTY-NINTH REPORT OF THE STATE ENTOMOLOGIST 19 



SUGAR beet webworm.- The occurrence of this insect (Lox- 

 ostege sticticalis (L.) ) was quite general throughout the State in 

 1941. Heavy infestations were reported from localized districts 

 which were fairly well distributed throughout the sugar beet grow- 

 ing areas. Control measures were necessary in these areas. In Yel- 

 lowstone and Carbon counties practically the entire sugar beet area 

 was sprayed at least once. The damage was limited almost entire- 

 ly to defoliation of the plants, the infestation not being severe 

 enough to injure the crown. Heavy infestations were recorded 

 in flax fields. Their feeding activities were confined to stripping 

 of the leaves so it was difficult to estimate the damage. This ap- 

 pears to be the first time that this insect has been reported in large 

 numbers in flax in Montana. The severity of the infestation in 

 a flax field in Pondera County was judged from the fact that 50 

 to 70 pupal cases could be obtained from sifting a square foot of 

 soil in the field. 



A heavy flight of second generation moths appeared but over 

 90 per cent of these proved to be sterile. 



A moderate to heavy flight of moths was observed during June 

 of 1942. Owing to the high incidence of sterility among them, very 

 few eggs were laid. Some spraying was done in Yellowstone, 

 Carbon, and Big Horn counties. The infestation was very light and 

 no damage was reported. Some second generation moths appeared 

 in the northern part of the State but all of these were sterile. 



spruce budworm.— An outbreak of the spruce budworm 

 (Arehips fumiferana (Clem.) ) occurred on the Gallatin Forest dur- 

 ing the summer of 1942. It was noted in large numbers on the east 

 slope of the Bridger Range, and considerable damage was done to 

 douglas fir (Pseudotsuga taxifolia) , engleman spruce (Picea engel- 

 manni), and alpine fir (Abies lasiocarpa) . A trip was made into the 

 area in the company of Mr. A. H. Abbott, Forest Supervisor, on July 

 10th, at which time the larvae were abundant. On August 9 no 

 larvae were found in the same area but injury to douglas fir, es- 

 pecially to some of the young trees, was very evident. 



The larvae collected in July were moderately heavily parasit- 

 ized. Two species of parasites were reared from this collection, 

 Glypta fumiferana Vier., and a species of Microgaster which is ap- 

 parently undescribed according to Mr. C. F. W. Muesebeck, to whom 

 the specimens were transmitted for determination. 



army cutworm.— During the spring of 1942 parts of the 

 State experienced the worst infestation of the army cutworm 

 (Chorizagrotis auxiliaris Grote) in several years. A large area in 

 eastern Montana was involved, and there was considerable local 

 crop injury. Some grasshopper bait was spread in the control of 

 these pests. 



pale western cutworm. — This pest (Agrotis othogonia 

 Morr.) has been extremely injurious in the State in years past. 



