NINTH ANNUAL REPORT STATE ENTOMOLOGIST S3 



The Ninth Annual Report of the State 

 Entomologist of Montana 



INSECT PESTS OF 1911. 



The Cabbage Butterfly (Pontia rapae Linn.). Common as 

 the cabbage butterfly is. the gardeners of the State are very little 

 informed regarding the method of controlling it. Many fear to 

 spray their cabbages with arsenicals, thinking that to do so would 

 make them poisonous. It has been demonstrated by a number of 

 experiment stations besides this one, that sprayed cabbag-e may 

 be eaten with safety and we have shown that this insect may 

 be controlled if a small amount of soap is added to the spraying 

 solution, thereby making the arsenical adhere to the waxy foliage 

 of the cabbage. 



The Diamond-back Moth (Plutella maculipennis Curtis). 

 This small insect probably stands third as a cabbage pest in Mon- 

 tana and is a very serious one. I. is so small that it almost 

 escapes attention, yet if preserit in large numbers it does muck 

 to check the growth of the cabbage, it is an introduced species 

 which has found its way all through the United States. 



The Beet Webworm {Loxostege sticticalis Linn.). This is 

 aaother pest of the sugar beet, which gets upon the leaves, in 

 some cases causing complete defoliation. A few inquiries were re- 

 ceived during the year, but not a large amount of damage was 

 done. 



The White-lined Sphinx {Deilephila lineata Fab.). The 

 large horn-tailed caterpillars of this species appeared in phenomenal 

 numbers at one point in the Yellowstone Valley. This is a native 

 Montana species which feeds on a large variety of weeds and crops. 

 It is not surprising that its large size and great abundance led to 

 a mild alarm among the property holders, although it is clear, 

 from the histoi-y of the species, that it is not likely to become a 

 real pest. It is easily controlled by spraying with arsenicals. 



Cutworms (Fam. Moetuidae). Nineteen hundred and elevea 



