Preliminary Study of IPI\/I Options for 

 Peaclies: i\/lajor Fruit-damaging Insects 



Karen I. Hauschild 



Department of Plant & Soil Sciences, University of Massachusetts 



Arthur T\ittle and Daniel R. Cooley 



Department of Microbiology, University of Massachusetts 



Ronald J. Prokopy 



Department of Entomology, University of Massachusetts 



At harvest, the most severe damage on peach fruit 

 is caused by true bugs (primarily insects in the group 

 Pentatomidae, stink bugs) and Japanese beetles. Fruit 

 may show scarring or fresh feeding wounds accompa- 

 nied by a gummy ooze. Often this injury is severe 

 enough that damaged fruit must be culled or, at the 

 very least, downgraded to processing quality. With 

 the greatest profitability gained from fresh-quality 

 peaches, growers need and want to keep insect-dam- 

 aged fruit at the lowest level that is economically and 

 environmentally feasible. 



There are three species of stink bugs that are known 

 to attack peaches and cause cat-facing injury: the 

 brown stink bug (Eiischistus sennis), the dusky stink 

 bug [E. nisrigmus), and the green stink bug 

 {Acrosternum hilare). These insects are all highly 

 mobile, and usually remain in the orchard for only a 

 short period of time. Stink bugs reproduce on the trees, 

 laying eggs on the lower surface of peach leaves. These 

 eggs are easily identified; they are barrel-shaped, shiny, 

 and appear in clusters of about seven eggs each. After 

 the eggs hatch, the young nymphs move into the or- 

 chard groundcover. Nymphs do little feeding on 

 peaches. Primary damage is the result of adult feed- 

 ing. Numbers of brown and dusky stinkbugs are great- 

 est within a month of shuck fall. Green stink bug num- 

 bers tend to increase throughout the growing season. 

 The most severe damage to peach fruit occurs between 

 petal fall and the time when fmits are 0.5-0.75 inch in 

 diameter. If fruit that is damaged during this time pe- 

 riod fails to abscise, at maturity, it is heavily scarred or 

 malformed (injury commonly referred to as "catfac- 

 ing"). As the fruits enlarge, damage by stinkbugs is 



less dramatic. Injury results in holes with gummy exu- 

 date or dry, corky areas just below the fruit surface. 



The Japanese beetle {Popillia japonica) is a seri- 

 ous pest of ornamentals, grapes, and plants in the fam- 

 ily Roseaceae. Adult beetles chew on leaves and fruit. 

 Leaf damage ranges from minor tissue loss to com- 

 plete skeletonization. Fruit damage is restricted to the 

 fruit surface (surface damage), but can be extensive 

 and contaminated with beetle frass. Damage caused 

 by Japanese beetles often attracts other insects or dis- 

 ease organisms. Because Japanese beetles tend to 

 congregate, damage can occur very quickly and be- 

 come quite severe in a short period of time. 



The objective of this study was to determine the 

 incidence of damaged caused by these pests under re- 

 duced-pesticide regimes. Brown rot incidence from 

 the same study was reported [Fruit Notes 62(4)] . 



Materials & Methods 



Until pit hardening in early June, all treatment plots 

 received standard calendar-based pesticide applications 

 every 7 to 10 days. After pit hardening occurred, four 

 different treatment protocols were employed. These 

 treatments are outlined in Table 1 . Refer to Fruit Notes 

 62(4) for additional information on experimental de- 



Results & Discussion 



For Redhaven peaches (Table 2), the incidence of 

 stink bug damage was twice that of Glohaven (Table 

 3), while the incidence of Japanese beetle damage was 



Fruit Notes, Volume 63 (Number 2), Spring, 1998 



13 



