Effect of neem seed extract on feeding, growth, survival, and reproduction of Diaprepes abbreviatus (Coleoptera: Curculionidae).
A commercially available neem seed extract, Neemix 4.5, containing 4.5% azadirachtin (AZA), was assessed for biological activity against the root weevil Diaprepes abbreviatus (L.), an important exotic insect pest of Florida citrus. Laboratory bioassays against neonatal and 3-wk-old larvae fed sliced carrot treated with Neemix produced dose-dependent larval mortality and reduced fresh weights among survivors of treatments. The weight response was greater than the mortality response for both larval age groups. Neonates treated with 45 mg/liter AZA weighed 60% less than those in the control after 4 wk. Three-week-old larvae treated with 45 mg/ liter AZA weighed 30% less than those in the control after 5 wk. When neonates were exposed to insect diet incorporated with Neemix, reductions in larval survival and weight were observed at concentrations as low as 4.8 mg/liter AZA after 6 wk. Larval growth was inhibited by >97% with 42.9 mg/liter AZA in the diet. A soil drench containing 30 mg/liter AZA reduced the survival and weight gain of neonates added to potted citrus and provided protection to the roots in a greenhouse experiment. A concentration of 90 mg/liter AZA was required to provide protection of citrus roots against 4-wk-old larvae. Reproductive effects were observed when adult weevils were fed foliage treated with Neemix. The numbers of larvae hatching per egg mass were reduced by 27% and 68% at 30 and 90 mg/liter AZA, respectively. These results suggest that Neemix should be further evaluated for use in integrated pest management (IPM) programs of citrus.
Weathersbee
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AA
aweathersbee@ushrl.ars.usda.gov
Tang
Y Q
YQ
D000818:Animals; D001681:Biological Assay; D001517:Coleoptera / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology; D005247:Feeding Behavior / Q000187:drug effects*; D007306:Insecticides / Q000494:pharmacology*; D007814:Larva; D036701:Limonins; D010936:Plant Extracts; D012098:Reproduction; D012639:Seeds; D014315:Triterpenes / Q000494:pharmacology*
D007306:Insecticides; D036701:Limonins; D010936:Plant Extracts; D014315:Triterpenes; C010329:azadirachtin