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Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 4/29/2010 Publication Date: 8/1/2010 Citation: Tillman, P.G. 2010. Parasitism and predation for stink bug (Heteroptera: Pentatomidae) eggs in Georgia corn fields. Environmental Entomology. 39(4):1184-1194. 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 biological control of stink bugs in corn. Therefore, this 6-yr on-farm study was conducted to examine egg parasitism and predation of stink bugs associated with corn in Georgia. Naturally-occurring stink bug eggs were parasitized by seven species of egg parasites. Generally, percentage parasitism of naturally-occurring eggs was higher than predation of eggs. Except for two species, the same species of egg parasites that attacked naturally-occurring egg masses of N. viridula and E. servus also parasitized egg masses of these bugs hung from corn leaves. Percentage parasitism per egg mass was either higher than or equal to, but never lower than, percentage predation per egg mass for eggs of N. viridula and E. servus that were placed in corn. In conclusion, the results of this study indicate that both egg parasitism and egg predation are important mortality factors impacting stink bug populations in corn. Technical Abstract: Three species of phytophagous stink bugs, Nezara viridula (L.), Euschistus servus (Say), and Oebalus pugnax pugnax (F.), and the predatory stink bug, Podisus maculiventris (Say), occur on corn, Zea mays L., in Georgia. Very little information on natural biological control of these stink bugs in corn is available in the literature. Thus, this 6-yr on-farm study was conducted to examine egg parasitism and predation of stink bugs associated with corn. Naturally-occurring stink bug eggs were parasitized by seven species of egg parasitoids, Trissolcus basalis (Wollaston), Telenomus podisi Ashmead, Trissolcus thyantae Ashmead, Trissolcus brochymenae (Ashmead), Trissolcus euschisti (Ashmead), Telenomus calvus Johnson, and Ooencyrtus spp. Not surprisingly, T. basalis was the major egg parasitoid of N. viridula, and T. podisi was the predominant species emerging from eggs of Euschistus servus and Podisus maculiventris. Trissolcus basalis also attacked eggs of E. servus and P. maculiventris. Telenomus podisi was the only parasitoid that parasitized egg masses of all four stink bug species and was the only species that parasitized O. p. pugnax eggs. Eggs of E. servus were attacked by the greatest diversity of egg parasitoids in comparison eggs of the other three stink bug species, and E. servus was the only species parasitized by T. euschisti and T. thyantae. Trissolcus calvus only parasitized P. maculiventris eggs. For naturally-occurring eggs masses, overall percentage total mortality for all stink bugs ranged from moderately low to very high. Generally, percentage parasitism of eggs was higher than predation of eggs. Except for T. calvus and Ooencyrtus spp., the same species of egg parasitoids that attacked naturally-occurring egg masses of N. viridula and E. servus also parasitized sentinel egg masses of these bugs. Percentage parasitism per egg mass was either higher than or equal to, but never lower than, percentage predation per egg mass for sentinel eggs of N. viridula and E. servus. In conclusion, the results of this study indicate that both egg parasitism and egg predation are important mortality factors impacting stink bug populations in corn. |
