86 APPLE GROWING IN CALIFORNIA. 



The Green Apple Aphis. 



(Aphis pomi.) 



The little shiny black, oblong eggs on the new growth of apple twigs 

 during the winter season, have been seen by practically every apple 

 orchardist. These are the eggs of the green apple aphis, laid there by 

 a small green plant louse in the fall. As the buds begin to open in the 

 spring these eggs hatch and the little dark green colored lice immediately 

 begin feeding upon the new growth. These first spring lice, which 

 hatched from the overwintering- eggs, are known as stem-mothers. 

 When they become mature after a couple of weeks of feeding they give 

 birth to living young of a second generation. These in turn do likewise, 

 and a number of generations are developed throughout the season. 

 Many individuals after the second generation develop wings, and thus 

 may fly about from tree to tree and orchard to orchard, spreading the 

 infestation. In the fall true males and females are developed. These 

 are wingless and may be distinguished from the agamic forms by their 

 color, which is yellow instead of dark green. The females deposit the 

 eggs previously described. Their injury is done principally to the 

 leaves, although in bad cases the fruit and even tender twigs may be 

 attacked. The sap is sucked from the parts upon which feeding takes 

 place. A curling of the leaves is a good sign of the presence of this in- 

 sect. Ants feed abundantly upon the excrement or honeydew, and are 

 always present in annoying numbers when infestation occurs. Pear, 

 quince and hawthorn are subject to attack, as well as the apple. 



A thorough spraying with Black Leaf "40" and soap, at the strength 

 recommended for woolly aphis, or distillate or oil emulsion in the spring 

 when eggs are hatching, is effective. Any of these sprays may be used 

 later in the season to advantage. Lime sulphur, 1 part to 10 parts of 

 water, is supposed to possess some virtue as a dormant spray for the eggs. 

 Observations made in Colorado by the Avriter did not justify its use, 

 except when it was put on just as the eggs were beginning to hatch 

 early in the spring. If applied before hatching time it may have some 

 virtue, but results attained have been variable. 



The Purple Apple Aphis. 



(Aphis sorbi.) 



This is without doubt the most serious aphid pest of the apple, as far 

 as their effect upon the fruit is concerned. Like the green apple aphis, 

 they spend the winter in the form of small black eggs on apple trees, 

 which hatch very early in the spring. Almost before the buds have 

 begun to swell perceptibly, the little blackish colored lice may be seen 

 hanging on the outside waiting for them to open. Feeding begins imme- 

 diately upon the bursting of the buds. After about three weeks' time 

 these stem-mothers have become mature and reproduction without egg- 

 laying begins. 



The second generation is purplish in color, the lice being covered with 

 a powdery secretion. Feeding takes place very generally on the leaves, 

 close to the clusters of young apples, and more rarely on the apples 

 themselves, which are injured to such an extent that they become stunted 

 and not only fail to mature, but are distorted so badly that the variety 

 may not be recognizable. 



