TWENTY-SIXTH REPORT OF STATE ENTOMOLOGIST 25 



IMPORTANT INSECTS OF THE YEARS 1935-1936 



THE PALE WESTERN CUTWORM 



The abundance of pale western cutworms (Agrotis ortho- 

 gonia MorrJ is closely related to rainfall. When the May and 

 June rainfall is low, conditions are favorable to cutworm in- 

 crease. With two consecutive seasons of low rainfall (less than 

 3 inches) in May and June, a great increase in this cutworm may 

 be expected. Twelve counties (Teton, Pondera, Glacier, Toole, 

 Liberty, Hill, Chouteau, Blaine, Phillips, Valley, Fergus, and 

 Cascade) are facing such a situation in 1937. More damage to 

 grain crops was done in some of these counties in 1936 by pale 

 western cutworm than for many years, with the possible excep- 

 tion of 1932. As soon as rainfall data were avilable last summer 

 a warning was sent out relative to the danger of cultivating 

 summer fallow in the above areas during the period of August 

 15 to September 15. Cultivation or seeding operations at that 

 time breaks the slight crust which has been formed by any light 

 rains and makes the soil very attractive to the female moths for 

 depositing their eggs. 



So far as winter wheat is concerned, the die is cast. The 

 eggs have been laid and next spring they will hatch into young 

 cutworms. More or less the same condition is true of land on 

 which spring wheat or other grain is to be seeded. If cutworms 

 are going to be present next season on that land, the eggs are 

 already present. There is this difference, however. In Alberta 

 it has been found that the very young larvae cannot withstand 

 starvation. After the eggs hatch the young worms must have 

 some green food or they die. This offers some hope and sug- 

 gests the possibility that if the land is not seeded for a few days 

 following its thorough preparation for seeding, many of the 

 insects may be starved out. The effectiveness of such an at- 

 tempt at control would depend on knowing when the eggs hatch. 

 An effort will be made this coming spring to give farmers in the 

 threatened region this information. 



SAY'S PLANT BUG 



Say's Plant Bug was not so noticeable in 1936 on account 

 of the reduction of wheat by drought and grasshoppers. Never- 

 theless they were numerous over the north-central area in 



