ARS | Publication request: Compatibility of Heterorhabditis indica (Rhabditida: Heterorhabditidae) and Hebrobracon hebetor (Hymenoptera: Braconidae) in biological control of Plodia interpunctella (Lepidoptera: Pyralidae)

Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 21, 2010
Publication Date: June 1, 2010
Citation: Shapiro Ilan, D.I., Mbata, G. 2010. Compatibility of Heterorhabditis indica (Rhabditida: Heterorhabditidae) and Hebrobracon hebetor (Hymenoptera: Braconidae) in biological control of Plodia interpunctella (Lepidoptera: Pyralidae). Biological Control. 54:75-82.

Interpretive Summary: The Indianmeal moth is a major pest of stored food products such as grains and nuts. Research toward developing non-chemical pest control solutions for this pest is warranted. The use of parasitic wasps and beneficial nematodes are two environmentally friendly biological pest control tactics that have shown promise for control of the Indianmeal moth. In this study, we investigated the compatibility of the two natural control agents (wasps and nematodes). We discovered that the combined use of nematodes and wasps caused higher mortality in Indianmeal moth larvae than when either agent was applied alone. However, the combination treatment of wasps and nematodes reduces the wasp’s reproductive potential (the nematodes can kill the wasps). In contrast, the nematodes are not negatively affected by the wasp’s presence. In fact, the nematodes indicated a preference for infecting Indianmeal moth larvae that were parasitized by the wasp compared with un-parasitized healthy larvae. We conclude that the combined application of nematodes and parasitic wasps for the control of Indianmeal moth may be beneficial if the detrimental effects of the nematode on the wasps can be minimized through optimal timing.

Technical Abstract: The potential for integrating the application of Heterorhabditis indica and release of Hebrobracon hebetor (in the management of Plodia interpunctella) was investigated. A combination of the nematode and the parasitoid was observed to increase the mortality of Indianmeal moth larvae but the increase was found to be additive instead of synergistic. The nematode was found to be virulent to the larvae of the parasitoid but not to the pupae and the adults. Adult female parasitoids that were exposed to both uninfected and nematode infected P. interpunctella larvae in a free choice arena were unable to distinguish between the two. In contrast, nematode infective juveniles preferentially infected parasitized host larvae compared with healthy unparasitized host larvae. Nematode reproduction was not significantly different in parasitized and unparasitized host larvae. The combined application of H. indica and H. hebetor for the control of P. interpunctella may be beneficial if the detrimental effects of the nematode on the parasitoid can be minimized through optimum timing.