6 Bulletin 332 



eggs of the green apple aphis, A. pumi, were very abundant on water 

 sprouts in an old unkept orchard near Scott's corner, a few luiles 

 from riainsboro, N. J., 1916-17. On 3Iay 1, some eight hundred 

 stem mothers were collected from the water sprouts in this orchard 

 and A. pomi made up 71 per cent of the total number, A. sorbi 26 

 per cent, and A. auence 3 per cent. This count, along with others, 

 shows that A. sorbi probably made up 25 to 30 per cent of the total 

 luimber of eggs. 



During the past dormant season, 1917-18, the fall migrants and 

 oviparous females were observed in a number of orchards through- 

 out the state and in the majority of places A. avence was the only 

 species present; A. pomi and A. sorbi were comparatively rare in 

 most orchards. The investigations during the past season deal only 

 with A. avenit. Three orchards were chosen for supplying mate- 

 rial: John H. Barclay's orchard, near Cranbury, N. J.; George 

 Smith's orchard near South River, N. J.; and J. L. Lippincott Com- 

 pany's orchard, near Riverton, N. J. 



All observations made in respect to the location of the eggs of 

 the different species and the time of hatching conform closely with 

 those made by Baker and Turner (2, 3) and other investigators. 

 The eggs of A. avence and A. sorbi, for the most part are deposited 

 under buds or in small crevices in the bark on second-year growth, 

 and to some extent on larger branches, 2 inches in diameter, and oc- 

 casionally on one-year growth. They are usually distributed even- 

 ly throughout the orchard. It has also been noted that varieties 

 of apple trees which retain their leaves the longest in the fall of the 

 year are apt to have the heaviest infestation. This is probably due 

 to the fact that the oviparous female feeds on the under-side of the 

 foliage and when the leaves fall from the tree she may disappear 

 with the leaves, or if she is located on the branches of the tree when 

 the leaves fall she is deprived of the opportunity to obtain food 

 which is probably essential to the development of the greatest num- 

 ber of eggs. The eggs of A. pomi are deposited on one-year growth, 

 particularly at the distal ends of water sprouts, and they are often 

 scattered over the smooth surface of the twig. Usually the infesta- 

 tion is local, the eggs being contined to a few twigs on a tr^e and also 

 not evenly distributed throughout the orchard. Frequently the 

 eggs of A. pomi are veiy abundant in young orchards ; this was true 

 of John H. Barclay's orchard in 1915. 



During 1917 the eggs of A. avence started to hatch about March 

 31, and, so far as observed, had completely hatched by April 6 or 7, 

 while the eggs of A. pomi and A. sorbi started to hatch about April 

 12 to 14, and completed hatching in a week or ten days. A. sorbi 

 apparently preceded A. pomi by two or three days, at least the stage 

 of development of the nymphs after all eggs had hatched indicated 



