Effects of GNA transgenic sugarcane on life history parameters of Parallorhogas pyralophagus (Marsh) (Hymenoptera : Braconidae), a parasitoid of Mexican rice borer

• Author(s): Bernal, Julio; Tomov, B.;
• Abstract: Parallorhogas pyralophagus (Marsh) is the principal parasitoid of the Mexican rice borer [Eoreuma loftini (Dyar)], the primary pest of sugarcane in south Texas. Insect resistant transgenic sugarcane producing Galanthus nivalis agglutinin (GNA) was developed to improve control of E. loftini. The present laboratory study addressed whether over two consecutive generations transgenic sugarcane delivered via artificial diet has adverse host-mediated effects on P. pyralophagus life history parameters. The results of this study showed that a number of life history parameters were affected by transgenic, sugarcane, whereas others were not affected, and that effects varied between generations. In the first generation, adult longevity was increased by approximate to2 d, and cocoon to adult and egg to adult developmental times were prolonged by approximate to1 d in parasitoids exposed to transgenic sugarcane, whereas effects were not evident on adult size; egg load; egg to cocoon developmental time; rates of gain of longevity and egg load with adult size; and egg, larval, and pupal mortality. However, in the second generation, adult longevity was reduced by approximate to3 d, adult size by approximate to5%, egg load by approximate to24%, and rate of gain of longevity with adult size by approximate to21%, whereas effects were not evident on the rate of gain of egg load with adult size. It was concluded that although GNA transgenic sugarcane, ingested via E. loftini tissues, was not acutely toxic to F pyralophagus, the sublethal effects on life history parameters measured in this study must be considered in a broader context to determine their possible ecological significance.
• Publication Date: Jun 2003
• Journal: Journal Of Economic Entomology