MONTANA INSECT PESTS, 1947 AND 1948 13 



ALFALFA SEED CHALCID (Bruchophagus funebris) 



This insect is distributed over the entire clover and alfalfa 

 seed-producing areas of Montana where it is found to damage seed 

 production of these crops. Samples of seed obtained in 1947 from 

 the Camas Prairie section showed chalcid damage to apDroxi- 

 mately 40 percent of the seeds. It has also been a serious pest of 

 clover seed in the vicinity of Charlo. 



PEA APHIS {lUinoia pisi) 



The 1948 season showed higher populations of pea aphis in both 

 alfalfa and clover in western Montana than were present in 1947. 

 In some fields, populations were severe enough to necessitate the 

 application of control measures. 



POTATOES 



COLORADO POTATO BEETLE (Leptinotarsa decernlineata) 



The Colorado potato beetle was observed damaging potato 

 fields in the vicinity of Kalispell in 1947 and around Great Falls 

 in 1948. In both cases the infestation was severe enough to necessi- 

 tate a control program over much of the potato acreage. Some 

 damage to potatoes has been noted in the Bitterroot Valley during 

 the last two years. 



POTATO PSYLLID {Paratrioza cockerelli) 



On occasion the potato psyllid has been a serious pest in the 

 eastern part of the state. Surveys to determine its presence have 

 been conducted for the last two years throughout the potato grow- 

 ing areas of eastern Montana during the month of June. No adult 

 psyllids were found in the areas surveyed in either 1947 or 1948. 

 These areas were determined by previous investigations to be 

 the areas most likely to give an indication of general psyllid 

 populations. 



SUGAR BEETS 



SUGAR BEET WEBWORM (Loxostege sticticalis) 



In 1947 sugar beet webworms appeared in economic numbers 

 in Cascade and Teton counties and in Ravalli, Missoula, and Lake 

 counties. Heavy moth flights were observed in the spring of 1948 

 from Billings west to the Bitterroot and north to the Chinook- 

 Choteau area. Infestations of the webworm were spotted through- 

 out this entire region. Populations as high as 25-30 worms per 

 plant could be found on sugar beet plants and other hosts. Con- 

 siderable control work was carried on throughout the infested 

 areas. 



