24 



CIRCULAR 2 7 0, U. S. DEPARTMENT OF AGRICULTURE 



year. Young and adults are green, with black legs, and often with 

 yellowish heads. Some of the adults are winged, and these migrate to 

 other apple trees, thus spreading the infestation during the season. 

 The eggs are green when deposited in the fall, but later become glossy 

 black. 



CONTROL 



The control measures recommended for the rosy apple aphid are also 

 effective for this species. Since it remains on the trees throughout the 

 season and migrates from tree to tree, additional sprays may be nec- 

 essary, particularly on young trees or on nursery stock. Three- 

 fourths of a pint of the nicotine sulfate, to which is added 2 or 3 pounds 



Figure 25. — Proper stage at 

 which to spray for aphids. 



Figure 26. — Apple aphids 

 on apple foliage. 



of soap in solution or 1 pound of casein spreader to every 100 gallons 

 of spray, is very effective if applied thoroughly in order to reach the 

 aphids in the curled leaves. In hot weather, when the temperature 

 is above 80° F., the quantity of nicotine sulfate may be reduced to 

 one-half of a pint to 100 gallons, as nicotine is more effective in hot 

 weather than in cool weather. If bearing apple trees are to be sprayed, 

 this application may be combined very effectively with a summer oil 

 emulsion and used in place of one of the regular applications of lead 

 arsenate for the codling moth. 



Woolly Apple Aphid 



The woolly apple aphid (Eriosoma lanigerum (Hausm.)) attacks the 

 roots as well as the upper parts of the trees. Above ground it is found 

 chiefly on the trunks, limbs, and twigs, in wounds caused by pruning 

 or cultivating implements, and wherever the bark is tender (fig. 27). 

 Twigs become somewhat swelled and knotted as a result of its attacks. 

 The aphids are occasionally found on the fruit stems and in the calyx 

 ends of apples. Injury to the roots is not very important in the arid, 

 sandy areas of the Northwest, and in those areas it is more or less 

 limited to exposed roots. In the coastal sections, particularly in 

 heavy soil that may crack, the aphids penetrate to the roots, causing 



