22 MONTANA EXPERIMENT STATION BULLETIN 474 



BEAN ROOT APHID (Trifidaphis phaseoli) 



The bean root aphid was found in the Crow Agency area of 

 Big Horn County in 1950. It was not found or reported in 1949. 

 These aphids which suck the sap of the bean roots, are transported 

 to the bean roots from the roots of their alternate hosts (weeds) 

 by ants. The ants cultivate the aphids for their sweet honeydew 

 secretion. Bean root aphids are best controlled by eliminating the 

 ants with chlordane dusts or sprays. 



INSECTS DESTRUCTIVE OF GARDEN AND TRUCK CROPS 



CRUCIFERAE 



CABBAGE OR RADISH MAGGOT (Hylemya hrassicae) 



No serious outbreaks of cabbage or radish maggot were re- 

 ported during the last two years. This maggot is, however, a 

 perennial problem in nearly all Montana gardens. Two to three 

 applications of IV2 pounds of chlordane per acre, either as a spray 

 or dust, starting with the cotyledon stage, has given satisfactory 

 control. 



IMPORTED CABBAGE WORM (Pieris rapae) 



This common pest of cruciferae is usually present in most 

 Montana gardens. No severe outbreaks have been reported in the 

 past two years. Frequent applications of 5% DDT dust have pre- 

 vented serious imported cabbage worm damage. 



CABBAGE APHID (Brevicoryne brassicae) 



Cabbage aphids were only reported or observed in the Bitter- 

 root Valley during the past two years. In this area they were more 

 prevalent in 1949 than in 1950. The cabbage aphid is considered to 

 be a state-wide pest, but it probably was not prevalent in other 

 areas. 



ROOT CROPS 



ONION MAGGOT (Hylemya antiqua) 



The onion maggot which is commonly found throughout most 

 of the state was reported by gardeners only in Musselshell and 

 Madison counties during 1949 and 1950. Observations in the west- 

 ern portion of the state indicate that this pest is becoming in- 

 creasingly prevalent in that area. 



ASPARAGUS 



ASPARAGUS BEETLE (Crioceris asparagi) 



The asparagus beetle is present in western Montana, particul- 

 arly in the Flathead Lake area. Apparently this insect has not 

 been an economic factor inasmuch as the damage has occurred late 

 in the season after the plants have gone to seed. 



