Submitted to: Journal of Entomological Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/20/2010
Publication Date: 4/1/2011
Citation: Tillman, P.G. 2011. Parasitism and predation of stink bug (Heteroptera:Pentatomidae) eggs in sorghum in Georgia. Journal of Entomological Science. 46(2):171-174. Interpretive Summary: Stink bugs have increased in importance as pests of agricultural crops over the past several years, but there is very little information available on natural biological control of stink bug eggs in sorghum which can serve as a trap crop for these pests in farmscapes associated with corn, cotton, and peanut. Therefore, this on-farm study was conducted to examine parasitism and predation of eggs of the southern green stink bug and the brown stink bug in sorghum in Georgia. Stink bug eggs were parasitized by four species of egg parasites and eaten by several species of predators. Generally, percentage parasitism of eggs was higher than predation of eggs, but combined morality for N. viridula eggs was moderately low, '28%, while combined mortality for E. servus eggs was moderately high, '47%. The provision of food by the addition of a nectar plant in a sorghum trap crop could possibly enhance parasitism of the stink bug egg parasitoids in this habitat.
Technical Abstract: Stink bugs, including the southern green stink bug, Nezara viridula (L.), and the brown stink bug, Euschistus servus (Say), are responsible for losses of millions of dollars in reduced yields and costs of control in cotton. Sorghum, Sorghum bicolor (L.) Moench, has been shown to be an effective trap crop for N. viridula in cotton in corn-cotton and peanut-cotton farmscapes in Georgia. This paper is a report on parasitism and predation of eggs of N. viridula and E. servus in strips of sorghum in these farmscapes in 2002, 2004, 2005, and 2006. To determine species of parasitoids attacking naturally-occurring eggs of N. viridula and E. servus, sorghum was examined weekly for the presence of stink bug egg masses during the growing season. To assess predation and parasitism of E. servus and N. viridula eggs and determine species of parasitoids attacking these eggs, egg masses of these two insect species were placed as sentinels in sorghum. A total of four species of scelionid parasitoids, Trissolcus basalis (Wollaston), Telenomus podisi Ashmead, Trissolcus thyantae Ashmead, and Gryon obesum Masner emerged from naturally-occurring and sentinel egg masses of stink bugs in sorghum. All four parasitoid species attacked N. viridula egg masses, and the former three parasitoid species attacked E. servus egg masses. Trissolcus basalis was the most prevalent parasitoid of N. viridula eggs, and Telenomus podisi was the predominant parasitoid species emerging from eggs of E. servus. For both stink bug species, overall percent parasitization was significantly higher than percent predation, but combined mortality was moderately low ('28%) for N. viridula and moderately high ('47%) for E. servus. The provision of food by the addition of a nectar plant in the sorghum trap crop could possibly enhance parasitism of the stink bug egg parasitoids in this habitat.