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MONTANA EXPERIMENT STATION BULLETIN 408 



be of considerable importance not only to the farmer but to the 

 beekeeping industry as well. 



The sweet clover weevil is a grayish snout beetle, from one- 

 eighth to three-sixteenths of an inch long. It may occur in large 

 numbers, from 25 to 100 per square yard having been reported. 

 Injury to this crop should be watched for, and if beetles answering 

 the above description are found they should be sent to the State 

 Entomologist's Office at Bozeman. 



Some insecticidal tests were tried in Ontario, but as yet no 

 satisfactory method of control has been developed. 



pea weevil.— During the past few years this pest (Laria pi- 

 sorum (Linn.) ) has increased in importance in some parts of Mon- 

 tana. The two areas most heavily infested at the present time in- 

 clude a region from the vicinity of Missoula to the north and west 

 to the State line, and the Valley of the Clark's Fork of the Yellow- 

 stone from Bridger and Roberts north to the Yellowstone and in- 

 cluding some areas near Billings. These areas were surveyed dur- 

 ing the latter part of June, 1942, and although the pea weevil is 

 widespread in them, there were but isolated spots where it was 

 at all abundant. 



Figure 6. Pea weevil. Right, adult beetle ready to emerge from dried 

 pea; left, injury to green pea caused by entrance of newly hatched larva. 

 Greatly enlarged. 



The apparent increase in numbers of pea weevils recently may 

 be the result of at least two things. In the first place peas contain- 

 ing up to 10 per cent weevils were used for seed in some parts of the 

 State during the spring of 1942. This certainly had an effect in the 

 local increase of the species in areas where such seed was planted. 

 In the second place, most of the State has experienced a series of 

 mild winters with considerable snowfall which would allow more 

 of the pests to live through the winter out-of-doors. The survey 

 indicated clearly that this was taking place. 



