16 MONTANA EXPERIMENT STATION BULLETIN 457 



OYSTER SHELL SCALE {Lepidosaphes ulmi) 



Oyster shell scale is present in all fruit-growing areas of the 

 state. In addition to attacking fruit trees, it often attacks shade 

 trees and ornamental plantings. It may become a serious problem 

 where home and commercial orchardists do not apply proper 

 insecticidal sprays. 



WOOLY APPLE APHIS (Eriosoma lanigerum) 



During the last two years, there has been an increase in wooly 

 aphis populations in apple orchards where D.D.T. has been used 

 for codling moth control. This increase is thought to be due largely 

 to a reduction of aphis predators brought about by the action of 

 D.D.T. 



APPLE APHID (Aphis pomi) 



This is a common pest thoughout the apple-growing regions 

 of Montana. During the last biennium, infestations have been 

 rather constantly becoming a problem in unsprayed orchards. 



ROSY APPLE APHIS (Anuraphis roseus) 



Wherever apples are grown in this state, the rosy apple aphis is 

 commonly encountered. During the last two years, the population 

 levels of this insect have apparently remained static. A spray 

 program appears necessary to prevent damage. 



EYE-SPOTTED BUD MOTH (Spilonota ocellana) 



As far as is known, this pest, which feeds on the buds and 

 blossoms of apples, cherries, and plums, is widely distributed over 

 western Montana. The populations of this insect have increased 

 to such an extent that they are now becoming of economic 

 importance. 



CHERRIES 



BLACK CHERRY APHIS (Myzus cerasi) 



This is one of the principal cherry pests of the Flathead area. 

 Infestations of this aphis have been severe enough during the past 

 two years to necessitate the application of control measures. 



CHERRY FRUIT FLY {Rhagoletis cingulata) 



At the present time, this pest is known to occur in sour 

 cherries in certain districts of the Flathead area. In 1947, unsprayed 

 sour cherry trees were found to have 5 to 10 percent wormy fruit. 

 As yet, little is known about the adult fly, its activities, or its 

 distribution. 



