APHIDS INJURIOUS TO ORCHARD FRUITS. 



41 



on the foliage and twigs, and in regions Avhere the}^ are likely to be 

 troublesome, as on nursery stock in sandy situations, carefid watch 

 should be made for their first appearance. 



The black cherry aphis is likely to be in evidence each year on 

 cherries. The insect winters on the trees in the egg stage and the 

 eggs hatch somewhat in advance of the opening of the buds. Since 

 this species causes a decided curling of foliage so that later treatments 

 are not satisfactory, the effort should be made to destroy the stem- 

 mothers as the buds 

 are breaking. 



DESTRUCTION OF WINTER 

 EGGS. 



Considerable ex- 

 perimenting has been 

 done wdth sprays dur- 

 ing the dormant pe- 

 riod of trees to de- 

 stroy the W'inter eggs 

 of aphids (fig. 8), on 

 the shoots, twigs, and 

 branches. Thus far 

 results have not been 

 satisfactory, and 

 w^hile sprays may re- 

 sult in the destruction 

 of some of the eggs, 

 serious aphid injury 

 occurs very frequently 

 in orchards well 

 sprayed for the San 

 Jose scale. 



In the course of pruning young trees it is often possible to remove 

 many shoots covered with eggs, which should be destroyed. 



CONTROL OF APHIDS ON CURRANT, GOOSEBERRY, AND GRAPE. 



All of the important aphids attacking the currant and gooseberry 

 pass the winter on these plants in the egg stage, the stem-mothers 

 hatching as the leaf buds are opening and soon causing the leaves 

 to become more or less pitted or curled. It is especially important, 

 therefore, to spray as the shoots are pushing out, to destroy the stem- 

 mothers before they are protected by the distorted foliage. In spray- 

 ing for these insects later in the season the liquid should be directed 

 upward to wet the insects on the underside of the leaves. 



The grapevine aphis, while often abundant on the terminal grow^th, 

 is rarely very injurious. It is much subject to parasitic and predatory 



Fig. 30. — Yoimg apple shoot too far expanded for sueccs 

 ful aphid spraying. Enlarged. (Original.) 



