60 



CIRCULAR 270, U.S. DEPARTMENT OP AGRICULTURE 



CONTROL 



The use of oil emulsions for dormant spraying has simplified the 

 problem of controlling the green peach aphid. An emulsion contain- 

 ing 4 percent of oil, as used for the San Jose scale, affords very good 



control, if applied just as the 

 buds begin to swell. It must 

 be used after the eggs have 

 hatched and before the buds 

 have opened. If it is necessary 

 to use lime-sulphur solution for 

 the peach twig borer, nicotine 

 sulphate (40 percent nicotine) 

 should be added to it in the 

 proportion of three fourths of a 

 pint to 100 gallons of spray, as 

 the lime-sulphur is not effective 

 in controlling the aphids. 

 If neither the oil emulsion nor 

 the lime-sulphur solution is 

 used, soap or casein spreader 

 should be added to the nicotine 

 spray to increase its power of 

 wetting the insects. 



BLACK PEACH APHID 



The black peach aphid (Anur- 

 aphis persicae-niger Smith) is 

 seldom seen in the Pacific North- 

 west, although it does occur in 

 Idaho and possibly elsewhere, 

 having been introduced from 

 the Eastern States, where it is 

 native. It feeds on the roots as 

 well as on the young twigs and 

 leaves of peach and apricot trees, 

 and is therefore potentially a 

 pest of considerable importance, 

 since root-feeding forms are 

 often more difficult to control 

 than those aboveground. 



LIFE HISTORY 



The black wingless forms live 

 on the roots throughout the 

 year, and in the spring some of 

 them migrate to the new growth 

 aboveground, where they in- 

 crease rapidly (fig. 71). As they 

 become crowded, winged forms 



develop, which fly to other trees and establish new infestations. The 



aerial forms usually disappear by midsummer. 



FiorKE 71.— Black peach aphids on peach shoot. 



