Investigation of Scarring of Fruit by Apple Redbugs 201 



It is apparently due to unusual growing conditions that the injuries 

 caused by these several agencies produce the abnonnal bulging growth 

 under the scar. This warting of the scars produces peculiar results in 

 some cases (fig. 49), and may be explained by accelerated growth late in 

 the season. After the middle of August apples usually grow very slowly, 

 but occasionally favorable rains after that date force new and rapid growth. 

 When growth is accelerated in the fruit it is apparent that considerable 

 pressure is exerted on the old and more-or-less hardened skin of the apple. 

 The scar tissue when it is present, being the most recently formed and 

 tender, gives way first and new cells are formed beneath the area. In 



Fig. 46. WORK of heterocordylus malinus on twenty ounce apples 



tough-skinned apples such as the Ben Davis (fig. 49), the new growth is 

 forced most completely thru the newly formed scar tissue. 



injuries that may be confused with redbuc injury 



It is apparent that in certain cases in the past the work of redbugs has 

 been credited to the plum curculio {Conotrachelus nenuphar). When the 

 plum curculio first comes from hibernation it is a voracious feeder and 

 attacks the young apples as soon as they are formed. The early-feeding 

 punctures are often not accompanied with egg laying, and it was noted 

 in these observations that such of the young fruits as were fed upon were 

 so severely injured that they dropped. After the apples are large enough 

 to withstand injury, the curculio punctures are invariablv accompanied 



