Trichoplusia ni(Lepidoptera: Noctuidae) Survival, Immune Response, and Gut Bacteria Changes after Exposure toAzadirachta indica(Sapindales: Meliaceae) Volatiles

Abstract

Abstract Volatile organic compounds (VOCs) produced by the neem tree (Azadirachta indica A. Juss.; Sapindales: Meliaceae) are known to alter growth and development of several insects. Additionally, the insect's gut microbiota and immune response are key components in insect development and have been linked to increased resistance to insecticides. In the present study, larval mortality, immune response, and intestinal bacteria changes in the cabbage looper, Trichoplusia ni (Hubner) (Lepidoptera: Noctuidae), induced by VOCs of dried and milled neem leaves, stems, and bark were investigated. Exposure of neonates to 10 g of mixed dried leaves and stems resulted in 79 and 63% mortality of laboratory and field T. ni strains, respectively. In addition, differences were observed in larval weights and pupal sizes during 30 d of incubation. Further studies included transcript amplification of enterobacteria genes and genes related to immune responses and chemical synthetic insecticide resistance. Midguts from the V...