Soares, G. G.,Jr., Lewis, W. J., Strong-Gunderson J. M., Waters, D. J., and Hamm, J. J. INTEGRATING THE USE OF MVP BIOINSECTICIDE, A UNIQUE BT-BASED PRODUCT,
WITH NATURAL ENEMIES OF NOCTUID PESTS: A NOVEL CONCEPT IN COTTON IPM Proceeding, Second Canberra Bacillus thuringiensis Meeting 1994 133--145

Abstract

Developing integrated pest management (IPM) systems that build on the natural control agents already present in an agro-ecosystem requires a thorough understanding of the biological agents present and their interactions with their host/prey pest species and the crop plant. With this knowledge base the appropriate pesticides and other farm management practices can be integrated into an effective pest management system. Biopesticides because of their selectivity are well suited to being key components in such systems, because they lack direct activity on natural enemies. However, a major problem with pesticides, even modern selective bioinsecticides, is that they can cause disruptions to the natural enemy complex by removing the food/host resource required by parasitoids and predators. Scientists have suggested that sub-lethal or slow-killing doses could potentially provide immediate control of crop damage by a pest while stimulating the buildup of its natural enemies.

MVP Bioinsecticide, a Bacillus thuringiensis based insecticide and Mycogen's first product to be developed and commercialized using the CellCap biological encapsulation process, has some unique attributes including the use of a selected high potency toxin and enhanced foliar persistence, as first demonstrated in small plot trials on vegetables in the U.S.A. In the field these features have translated to excellent efficacy in a variety of crops. Field trials on cotton in Australia, for example, have shown MVP to provide superior levels of control of Helicoverpa armigera and Helicoverpa punctigera larvae in comparison with other Bt-based products. These results are reported here.

It was felt that the unique features of MVP could potentially make it particularly well adapted to integration with natural enemies in an IPM strategy. A project was initiated to investigate whether MVP could be used in this manner against the beet armyworm, Spodoptera exigua, ant the cotton bollworm, Helicoverpa zea. We found in laboratory and greenhouse studies that larvae of S. exigua and H. zea intoxicated with MVP at sub lethal doses can serve as suitable hosts for the attraction and reproduction of the hymenopterous parasitoid, Cotesia marginiventris. In fact, data indicted that the intoxicated caterpillars were more favorable than normal, untreated caterpillars for the the buildup of natural enemies because they are slower moving and are available in the suitable stage longer due to the severe growth retardation. Indications also suggest that this phenomenon is available for various other pest/natural enemy/pesticide interactions. Thus, a potential approach for true compatibility of pesticides and biological control agents with broad implications has been demonstrated.