ORCHARD INSECTS OF THE PACIFIC NORTHWEST 



63 



carnation, chrysanthemum, snapdragon, and violet. In the fall 

 winged forms return to the peach and produce a wingless generation 

 that lays the overwintering eggs. 



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-sulfur 

 solution for the peach twig borer, 

 nicotine sulfate (40 percent nico- 

 tine) should be added to it in the 

 proportion of three-fourths of a 

 pint to 100 gallons of spray, as 

 the lime-sulfur is not effective in 

 controlling the aphids. If neither 

 the oil emulsion nor the lime- 

 sulfur 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 (Anu- 

 raphis 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 na- 

 tive. 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 above ground. 



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 above 

 ground, where they increase 

 rapidly (fig. 71). As they be- 

 come crowded winged forms de- FlGURE 71 ._ B iack peach aphid, on 

 velop, which fly to other trees peach shoot. 



