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ARS Home » Midwest Area » Ames, Iowa » Corn Insects and Crop Genetics Research » Research » Publications at this Location » Publication #146875
Title: GROWTH, DEVELOPMENT, AND SURVIVAL OF NOSEMA PYRAUSTA-INFECTED EUROPEAN CORN BORERS (LEPIDOPTERA: CRAMBIDAE) REARED ON MERIDIC DIET AND CRY1AB

Author
item Reardon, Brendon
item Hellmich Ii, Richard
item Sumerford, Douglas
item Lewis, Leslie

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/1/2004
Publication Date: 8/1/2004
Citation: Reardon, B.J., Hellmich II, R.L., Sumerford, D.V., Lewis, L.C. 2004. Growth, development, and survival of Nosema pyrausta-infected European corn borers (Lepidoptera: Crambidae) reared on meridic diet and Cry1Ab. Journal of Economic Entomology. 97:1198-1201.

Interpretive Summary: The European corn borer is a moth that causes injury to corn leaves, stalks, and ears. Genetically modified corn hybrids that have a gene from a toxic bacterium are used to manage the European corn borer in North America. European corn borers also are vulnerable to a common pathogen, Nosema pyrausta (Paillot). We examined the effect of feeding artificial diet and the toxin found in genetically modified corn on growth, development, and survival of Nosema-infected and uninfected European corn borer grubs (larvae). Infected larvae developed more slowly than uninfected larvae. Increasing the concentration of toxin in diet reduced larval development, and the reduction in development was increased by disease. Infected larvae weighed significantly less than uninfected larvae. Infected larvae have a higher level of mortality to toxin than uninfected larvae. This work has implications for resistance management of the European corn borer to genetically modified corn and demonstrates that it is important to determine whether disease-causing agents are present when testing the susceptibility of larvae to genetically modified corn hybrids. These results also provide a better understanding of the interactions of the European corn borer, disease, and the toxin found in genetically modified corn and are important to persons working with field collected insects.

Technical Abstract: Transgenic corn hybrids expressing crystal protein endotoxin genes from Bacillus thuringiensis Berliner are an increasingly popular tactic for managing the European corn borer, Ostrinia nubilalis (Hubner), in North America. Ostrinia nubilalis populations also are often vulnerable to the ubiquitous entomopathogenic microsporidium Nosema pyrausta (Paillot). We examined the effect of feeding meridic diet incorporated with purified Cry1Ab on growth, development, and survival of Nosema-infected and uninfected neonate O. nubilalis. Infected larvae developed more slowly than uninfected larvae. Increasing concentrations of Cry1Ab in diet reduced larval development, and this phenomenon was amplified by microsporidiosis. Infected larvae weighed significantly less than uninfected larvae. The relationship among Nosema infection, Cry1Ab concentration, and larval weight was fitted to an exponential function. The LC50 of infected larvae was about half that of uninfected larvae, indicating that infected larvae are more vulnerable to toxin. This work has implications for resistance management of O. nubilalis and demonstrates that it is important to determine whether N. pyrausta is present when testing susceptibility of larvae to transgenic corn hybrids.