|Ali, M. Ibrahim|
Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/24/2002
Publication Date: 7/1/2003
Citation: ALI, M., YOUNG, S.Y., FELTON, G.W., STREETT, D.A. INFLUENCE OF COTTON PHENOLOGY ON LARVAL DEVELOPMENT, AND PRODUCTION AND INFECTIVITY OF OCCLUSION BODIES OF NUCLEOPOLYHEDROVIRUS IN HELIOTHINES. JOURNAL OF ENTOMOLOGICAL SCIENCE. 2003. V. 38 (3). P.368-376.
Interpretive Summary: The H. zea insect virus is a commercially available biological control agent for the control of tobacco budworm and cotton bollworm. The fate and persistence of this virus in the field is an area of critical interest, and so our studies focus on the influence of the host plants on insect viruses. Virus production by infected insects in the field varied depending on the plant structure that was fed upon by the insect. This study demonstrates that virus production in the field will depend on the insect host diet.
Technical Abstract: Helicoverpa zea (Boddie) and Heliothis virescens (F.), reared on different cotton structures, were studied for larval growth and development, susceptibility to H. zea nucleopolyhedrovirus (HzNPV), and production of occluded virus (OBs). Larval weight of both species after 10 days of rearing differed with artificial diet the highest and square bracts the lowest weight. In both species, pupal weight and length of pupal developmental period were positively correlated with the larval weight, but length of the larval developmental period was negatively correlated with larval weight. Mortality from virus infection of H. zea and H. virescens larvae on squares, square bracts or flowers did not differ significantly among the structures. In both species, the number of viral OBs produced was greater in larvae fed flowers than those fed other structures, and was positively correlated with the weight gained by a healthy larva on that plant structure. The mean LC50 for OBs produced in H. zea or H. virescens larvae on square, square bract or flowers did not differ significantly. These results indicate that dietary difference in fruiting structures of cotton plants directly affects H. zea and H. virescens larval growth and development, and indirectly affects the production of virus by HzNPV-infected larvae.