364 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 12 



vious j'^ears, were repeated and the results obtained were almost identi- 

 cal with those of former years. 



Observations 



The eggs of A. avence were exceedingly abundant in many orchards 

 throughout New Jersey during 1918-1919, particularly in the central 

 and southern parts. This species was the only one present in John 

 Barclay's orchard near Cranbury, N. J. Consequently all of the 

 75,000 eggs of A. avenm used in the various spraying experiments 

 were obtained from this orchard. No other species was seen from 

 October 10 to December 10, 1918, when the females were deposit- 

 ing their eggs and also the nymphs observed after March 21, 1919, 

 were A. avence. The eggs were present in such large numbers that 

 they could be found on the smaller branches of all the trees and in 

 many cases on the large branches. Some of the trees (ten years old) 

 had eggs scattered over the entire length of the main trunk. The 

 50,000 or more eggs of A. pomi used in the various experiments were 

 collected from young orchards in the northern section of the state 

 near Lyons and Chester. The eggs of A . sorbi were not plentiful in 

 any of the orchards examined this past year. A large number of 

 orchards were observed during October, November and December, 

 1918, and wherever A. sorbi was seen the insects were few in number 

 compared with A. avence which was always present. The scarcity of 

 A. sorbi made it impractical to conduct experiments with this species. 



The great abundance of A . avence this year made it possible to observe 

 the injury done by this species. Where A. avence was the only species 

 present on a tree it was noted that comparatively few of the leaves 

 were curled even though the undersides of the leaves might have a 

 large number of aphides on them. In contrast to this it was noted 

 that whenever A. sorbi or A. pomi was present, even in small numbers 

 (2 to 6), the leaves were badly curled and stunted. All three species 

 were also found in large numbers on the petioles of the flowers in the 

 pink bud and flower stage and it is probable that they may injure the 

 set of the fruit. It is a well known fact that A. sorbi causes clusters 

 of small distorted fruit but, so far as known, this is not true of A. avence. 

 The stem mothers of A. avence give rise to nymphs, the majority of 

 which develop wings and these migrate to other plants, thus disap- 

 pearing almost completely by May 15 to 30. A. sorbi continues to 

 hve on the apple plant for several generations (3 to 4) and does not 

 completely disappear from the apple tree until the last of June, while 

 A. pomi lives on the apple tree the entire year. 



The observations made this season indicate that the injury caused 

 by A. avence is not serious under ordinary conditions; consequently if 



