VAIRIMORPHA-NECATRIX (MICROSPORIDA, BURENELLIDAE) AFFECTS GROWTH AND DEVELOPMENT OF HELIOTHIS-ZEA (LEPIDOPTERA, NOCTUIDAE) RAISED AT VARIOUS TEMPERATURES

The effects of the microsporidian parasite Vairimorpha necatrix (Kramer), a potential biological control agent, were evaluated in Heliothis zea (Helicoverpa) (Boddie) larvae raised in the laboratory at various temperatures (15, 20, 25, and 30-degrees-C). The target organ of infection was the larval fat body. Histopathologic changes in the fat body of the parasitized larvae included a congested appearance of the cells, decreased amounts of intracellular lipid, and loss of cellular structure and organization when the fat body filled with spores. Compared with controls, the growth and development of parasitized larvae were retarded. Larvae infected with V. necatrix were unable to pupate, thus disrupting the life cycle of H. zea.