Vera Krischik, krisc001@umn.edu and L. B. Flor, flor0119@tc.umn.edu. University of Minnesota, Department of Entomology, 219 Hodson Hall, 1980 Folwell Avenue, St. Paul, MN
Black vine weevil is an economically important pest of potted ornamentals and plants in landscapes. Since both larvae and adults of the weevil are found in soil, the soil inhabiting fungus, Beauveria bassiana (Bb) is a potentially important management tool. Replicate laboratory and greenhouse experiments in 2001 and 2002 compared the effectiveness of Bb and insecticides Talstar and Marathon when applied to soil and/or foliage against black vine weevil adults. Laboratory experiments at a relative humidity of 96% showed, for foliage application, survivorship was 0% on Talstar treatments in both experiments, whereas survivorship on Bb treatments was 36 and 38% in experiments 1 and 2. For soil application, survivorship was 0% on Talstar treatments in both experiments, while survivorship on Bb was 37 and 5% in experiments 1 and 2. Greenhouse experiments in 2001 at a relative humidity of 56% demonstrated that only Talstar on foliage significantly reduced survivorship of adult weevils. Greenhouse experiments in 2002 at a relative humidity of 96.4% resulted in adult survivorship on Bb 14 days after treatment of 53% and 7%, 0% on Talstar in both experiments, and Marathon had 60 and 0% in experiments 1 and 2 (averaging over foliar and soil application). These results indicated that Bb may be an adequate management tool when conventional pesticides are not permitted and relative humidity is high. Beauveria at higher dosage and RH significantly affected adult survivorship in 14 days, which is a short period in the one-year life cycle of larva and adult.
Species 1: Coleoptera Curculionidae
Otiorhynchus sulcatus (black vine weevil)
Keywords: biological control