SUSCEPTIBILITY OF DIAPREPES ABBREVIATUS (COLEOPTERA: CURCULIONIDAE) TO A COMMERCIAL PREPARATION OF BACILLUS THURINGIENSIS SUBSP. TENEBRIONIS

• Published in: The Florida entomologist Vol. 85; no. 2; pp. 330 - 335
• Main Authors: Weathersbee, A. A, Tang, Y. Q, Doostdar, H, Mayer, R. T
• Format: Journal Article
• Language: English
• Published: Lutz Florida Entomological Society 01-06-2002
• Subjects: age differences; Age groups; artificial diets; Bacillus thuringiensis; Beetles; biological control; biological resistance; body weight; citrus; Citrus reshni; Death; Diaprepes abbreviatus; Diaprepes root weevil; Diet; entomopathogen; entomopathogenic bacteria; Insect larvae; larvae; Larval development; lethal dose; Mortality; Nematode larvae; Research Papers; soil treatment; Weevils
• ISSN: 0015-4040; 1938-5102
• DOI: 10.1653/0015-4040(2002)085[0330:SODACC]2.0.CO;2

A commercial preparation of the microbial entomopathogen, Bacillus thuringiensis subsp. tenebrionis (Btt) was evaluated for biological activity against the Diaprepes root weevil, Diaprepes abbreviatus (L.). A reduction in survival was observed for neonatal larvae exposed to insect diet incorporated with Btt and in potted citrus treated with a Btt soil application. A treatment-induced, weight gain reduction for neonates was indicated only in the diet assay. Larvae exposed at 5 weeks old to diet treated with Btt demonstrated a dose-dependent mortality response. The mean ages for larval death ranged from 111 to 128 days among treatments. The LC50 for larvae in this age group was 6.2 ppm [AI] and the slope of the probit line was 2.29. The mortality response of larvae exposed at 12 weeks old also was dose dependent and the mean ages for larval death ranged from 130 to 141 days among treatments. The LC50 for larvae in this age group was 25.4 ppm [AI] and the slope of the probit line was 2.75. The delayed patterns of mortality that we observed among larvae treated at 5 and 12 weeks old indicates that disease is slow to develop in older larvae but that death occurs before maturation is completed.