198 



APPLIED ENTOMOLOGY 



The Apple Aphids. — There are three species of plant lice which attack 

 the apple more or less generally throughout the United States, and a 

 fourth is injurious in some parts of the country. In addition, a woolly 

 species feeding both on the twigs and roots is of importance and will be 

 treated later. 



The three species referred to are the Green Apple Aphis (Aphis pomi 

 DeG.), the Rosy Apple Aphis (Anuraphis roseus Bak. and Turn.) and 

 the Apple Grain Aphis {Rhopalosiphum prunijolice Fitch), the latter until 

 recently believed to be the same as a European species and generally 

 known therefore, as the European Grain Aphis. All three lay their eggs 

 in the fall on the twigs of the apple. In the spring the eggs of the Apple 

 Grain Aphis hatch a week or 10 days before those of the other two. The 

 young of all three kinds feed on the buds and become stem mothers which 

 when full-grown, differ in appearance. 



Fig. 188. Fig. 189. 



Fig. 188. — Green Apple Aphis {Aphis pomi De G.j, stem mother, about eight times 

 natural size. (Modified from Cornell Agr. Exp. Sta. Mem. 24.) 



Fig. 189. — Rosy Apple Aphis (Anuraphis roseus Bak. and Turn.), stem mother, greatly 

 enlarged. (Modified from Cornell Agr. Exp. Sta. Mem,. 24.) 



The Green Apple Aphis stem mother (Fig. 188) has a uniformly green 

 body, brown head and long, dark cornicles: the Rosy Apple Aphis stem 

 mother (Fig. 189) is greenish but blended with purplish brown, and the 

 cornicles are long, slender and dark; the body in this case is so dark as 

 to be often described as blue: the Apple Grain Aphis stem mothers 

 (Fig. 190) are yellowish-green, with a broad darker green stripe along the 

 middle above, from which several side branches pass off, and with rather 

 short, stout, yellowish cornicles. 



As the leaves develop the lice feed on them and in the case of the 

 Rosy Apple Aphis produce much curling. This is usually less pronounced 

 with the Green Apple Aphis and does not occur with the Apple Grain 

 Aphis. 



After a generation or two on the apple, winged forms (Fig. 191) begin 

 to appear and these migrate to summer food plants, except with the Green 

 Apple Aphis which remains an apple feeder throughout the year. The 



