Success of parasitism of Nezara viridula and Halyomorpha halys (Hemiptera: Pentatomidae) by Trichopoda pennipes (Diptera: Tachinidae) in the southeastern United States.

Abstract

Nezara viridula (L.) and Halyomorpha halys (Stål) are stink bug pests that damage fruit in a variety of crops throughout the southeastern United States. Trichopoda pennipes (F.) parasitizes N. viridula late instars and adults, however, little is known regarding parasitism of H. halys by this tachinid in systems where both stink bug species coexist. Thus, our main objective was to analyze patterns of T. pennipes parasitism for adult N. viridula and H. halys in corn, cotton, and soybean. We also assessed location of T. pennipes eggs on stink bug bodies as well as successful emergence from parasitized adults (ie at least 1 parasitoid egg per host body). Overall, the proportion of parasitized adults was higher for N. viridula compared to H. halys and higher in corn and cotton compared to soybean. Males were parasitized more often than females for both species. For N. viridula, T. pennipes developed to adults more often when eggs were laid on the ventral thorax. Supernumerary oviposition by T. pennipes was evident for both species. Even though T. pennipes readily oviposited on H. halys, new adults did not emerge from parasitized adults. For N. viridula, mortality of first instar T. pennipes was high due to their difficulty in entering the body; consequently, larval competition within the body was minimal. Adult T. pennipes emerged more often when two to four eggs were deposited on an adult stink bug. We conclude that T. pennipes prefers N. viridula as a host. Therefore, conservation biocontrol is an important management strategy for this pest.