Investigation of Scarring of Fruit by Apple Redbugs 197 



Roxbury and Golden Russet apples are subject to injury by redbugs. 

 All types of injury resulting on the former variety are shown in figure 34. 

 The early injuries produce deep pits, while the latest cause russet scars 

 that may frequently be hard to distinguish from the normal skin of that 

 variety. In figure 35 is shown a mature Roxbury apple which was injured 

 by fifth-stage nymphs between June 15 and June 18, on which the russet 

 scars healed so evenly with the normal surface that the apple would prob- 

 ably pass inspection as Grade A fruit. The Baldwin apple shown in 

 figure 36 is perfectly shaped, but it has the characteristic russet scars 

 developed from the late-feeding punctures of redbugs. In figure 37 is a 

 mature but stunted Baldwin apple, which recovered from injuries of the 

 feeding bugs while the adjoining fruit was so badly punctured that it died 

 and shriveled up but still clung to the tree. Late-feeding scars on a 



Fig. 40. WORK of apple redbugs on natural fruit of a slow-growing variety 



Bough apple are shown in figure 38; these are similar to the scars found 

 on Champlain and other early varieties. 



The appearance of redbug scars differs according to the variety and is 

 most interesting in some of the unnamed apples. In figure 39 are shown 

 the very conspicuous russet scars produced on an unnamed variety having 

 a light-colored transparent skin. Certain of the slow- growing natural 

 fruits (fig. 40) do not split about the woimd and produce the enlarged 

 scars that occur in varieties having more rapid growth. 



redbug injuries combined with injury by rosy aphis 



Under certain conditions the rosy aphis (Aphis sorhi) may develop 

 and feed on apples injured by redbugs. When this occurs the scars started 

 by the redbugs are much enlarged and otherwise changed by the aphides 

 (fig. 41). The work of the rosy aphis on apples tends to stunt the fruit 

 as well as to make it badly misshapen. In figure 42 is shown a Rhode 

 Island Greening apple much stunted by aphides and at the same time 



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