Aphids or Plant-lice Green Peach-aphis 



The aphis-lion (Fig. 18, Plate IX) and its parent (Fig. 19, Plate IX), 

 the lace-winged fly, are persistent aphid destroyers. (See pages 133 

 and 134.) 



The larvae of many Syrphus-flies, one of which is shown in Figure 13, 

 Plate VI, Page 21, devour large numbers of plant-lice. 



(a) GREEN PEACH-APHIS 



(Figs. 2, 9 and 10, Plate VIII, Page 25) 



As a sugar beet pest the green peach-aphis is of little importance. 

 However, under favorable conditions for its multiplication, it often 

 occurs in considerable numbers on the under side of beet leaves. 



NATURE OF INJURY 



Injury to sugar beets is due to the withdrawing of the sap from the 

 leaves by the aphids in feeding. This retards the growth of the plants. 

 The presence of lice is sometimes indicated by pale green or whitish 

 blotches on the upper side of the leaves. 



As its name indicates, the green peach-aphis is found on the peach 

 tree. It also feeds upon the plum tree. Its greatest damage is done to 

 these trees during early summer. 



METHODS OF CONTROL 



Spray infested peach and plum trees with lime-sulphur mixture 

 (See page 1 1 5) before the buds open in the spring to kill eggs and newly 

 hatched stem-mothers. After the buds open use black leaf 40. (See 

 page 114). 



The lice should be killed on the fruit trees. After they have mi- 

 grated to the beets it is practically impossible to kill them. 



DESCRIPTION 



The apterous or wingless lice (Fig. 9, Plate VIII, Page 25) are most 

 plentiful. A few winged lice (Fig. 10, Plate VIII, Page 25) may be found 

 among the wingless ones, especially during the latter part of the sum- 

 mer. These differ from the wingless individuals in coloring as well as 

 form. The most distinguishing mark is the dark patch on the abdomen. 



LIFE HISTORY 



In early spring the eggs, which are deposited on peach or plum 

 trees, hatch. In a few days the pinkish stem-mother, as the louse from 

 the egg is called, becomes mature and begins depositing her young on the 

 leaves. These young are not pink like their mother, but green, as shown 

 in Figure 9, Plate VIII, Page 25. In due time these green lice begin 

 giving birth to young. 



The lice of this third generation very largely become winged (Fig. 10, 

 Plate VIII, Page 25). These winged lice migrate to a number of annual 

 plants where the summer generations are produced. The list of about 

 eighty plants upon which this louse spends the summer includes nearly 

 every vegetable grown in the garden. 



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