MONTANA INSECT PESTS, 1947 AND 1948 15 



IMPORTED CABBAGE WORM (Pieris rapae) 



This is one of the more common pests of cruciferae in the state 

 of Montana. In some sections, it has become impossible to grow 

 these crops in gardens unless stringent control practices are carried 

 out. Generally, attacks of this pest are associated to some extent 

 with the cabbage looker {Autographa hrassicae) , and the diamond 

 back moth {Phitella maculipennis) . 



CABBAGE APHIS (Brevicoryne brassicae) 



As was the case with most aphis species, the cabbage aphis 

 was more prevalent in 1948 than in 1947. It is a state-wide pest 

 which will attack cabbage, cauliflower, turnips, etc., commonly 

 planted in the home garden. 



ROOT CROPS 



ONION MAGGOT (Hylemya antiqua) 



Present distribution records indicate that this insect is present 

 over most of Montana. During 1948 most of the damage occurred 

 in the western portion of the state with one grower near Hamilton 

 reporting an approximate 20 percent loss of onions due to the 

 presence of this pest. 



ASPARAGUS 



ASPARAGUS BEETLE (Crioceris asparagi) 



In 1948 this pest was found on Findley Point, Flathead Lake, 

 which is about ten miles from the point where it was first dis- 

 covered in the spring of 1946. It has now been observed to be 

 present from the south shore of Flathead Lake to Findley Point. 

 During the last two years, damage has occurred late in the season 

 after the plants have gone to seed. 



INSECTS INJURIOUS TO FRUIT CROPS 



APPLES 



CODLING MOTH (Carpocapsa pomonella) 



The codling moth is found in varying numbers wherever 

 apples are grown in Montana, with heavy infestations often occur- 

 ring in the Bitterroot Valley and in the Clarks Park Valley in 

 Carbon County. In 1947 the populations of codling moths were at 

 a low level in western Montana as a consequence of the very light 

 apple crop of the previous year. The numbers of codling moths 

 were higher in 1948 than in 1947. 



