Immunoliogical Responses of Hyphantria Cunea (Drury) (Lepidoptera: Arctiidae) to Entomopathogenic Fungi, Beauveria Bassiana (Bals.-Criy) and Isaria Farinosae (Holmsk.) Fr.

Abstract

Abstract Five morphological types of hemocytes were recognized in hemolymph of the 4th instar larvae of Hyphantria cunea (Drury). These hemocytes were: prohemocytes, plasmotocytes, granulocytes, oenocytoids, and spherulocytes. Tests were done on the effects of four isolates of the entomopathogenic fungus Beauveria bassiana (Bals.-Criy) (Fashand, spt-22, Ir-K-40 and 566), one isolate of Isaria farinosae (Holmsk.) Fr. (1872c), and latex-beads on the cellular immune defense mechanism and Phenoloxidase (PO) activity of H. cunea. Observation showed that plasmatocytes and granulocytes engulfed fungal pathogens by phagocytosis. The most phagocytosis occurred 30 and 60 min after injection but nodulation occurred in 3 and 6 hours, in all treatments. The total hemocyte count (THC) and granulocyte, and plasmotocyte numbers increased after the injection of spores. Phenoloxidase activity was determined in the presence of L-DOPA (L-3,4-dihydroxyphenylalanine), as a substrate in intervals, after injection of fungal spores, and latex beads. These studies demonstrated that B. bassiana is a promising candidate for biological control of H. cunea.