46 



CIRCULAR 2 7 0, U. S. DEPARTMENT OF AGRICULTURE 



dilution recommended by the manufacturer (usually about 1 gallon to 

 200 gallons of water). 



CHERRY INSECTS 



San Jose Scale 



The San Jose scale is not often very injurious to sour cherries, but it 

 does a great deal of damage to sweet cherries. As these trees usually 



grow large, the tops 

 are difficult to spray 

 thoroughly, and it is a 

 common thing to see 

 dead leaves clinging 

 to the upper branches 

 of large sweet cherry 

 trees during the win- 

 ter. This is an almost 

 sure indication that 

 these branches are 

 infested with the 

 scale. Treatment is 

 the same as for scale 

 on apple and pear 

 trees (p. 11). The 

 tops may often be 

 reached by climbing 

 into the trees and 

 spraying the tops 

 first. 



Black Cherry 

 Aphid 



The black cherry 

 aphid (Myzus cerasi 

 (F.)) is a large, shiny, 

 black aphid which 

 occurs on the young 

 foliage of cherry trees 

 and often interferes 

 with the terminal 

 growth. It is much 

 on dock more often found on 

 sweet cherry trees 



Figure 54. 



Larvae of dock sawfly feeding 

 leaves. X 4. 



than on the sour varieties, and is particularly injurious to young trees 

 and to nursery stock. The leaves of infested trees are severely curled 

 (fig. 55) and covered with a sticky honeydew. This aphid is a Euro- 

 pean species that has become prevalent in the United States. 



LIFE HISTORY 



The winter eggs, which are tucked in among the buds, hatch about 

 the time the buds burst, and the young develop rapidly on the new 

 growth, curling the leaves and feeding within the protection thus 



