Effect of entomopathogenic nematodes Steinernema species (steinernematidae: rhabditida) and Heterorhabditis bacteriophora (heterorhabditidae: rhabditida) on the digestive enzymes and midgut histology of the African migratory locust Locusta migratoria migratorioides (acrididae: orthoptera)

Abstract In some governorates of Egypt, the African migratory locust L. migratoria migratorioides is in a gregarious phase. Swarm development was successfully prevented by biological control agents. this work, two entomopathogenic nematode species, Steinernema sp. (SII)and Heterorhabditis bacteriophora (HP88) were investigated as natural enemies against fifth nymph and adult locusts at various concentrations (300, 600, 900, 1200, 1500 Infected juveniles/100 g. soil). To ascertain fatal activity 25 °C, nematode-inoculated sand method used. The species semi-field administered nymphs stages (25 ± 2 °C) 55–60% relative humidity with (3000, 6000, 9000, 12000, 15000 juveniles/kg. Protease, amylase, invertase, trehalase levels digestive enzymes both adults fed LC 50 nematodes significantly decreased, but lipase chitinase increased. Adult treated S . SII had basophilic epithelial cells, severe lumen hemorrhage, highly aberrant proliferating cytoplasm, whereas H. HP88 displayed necrosis an cell vacuoles, loss nucleus, goblet cells.