Author
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Aldrich, Jeffrey |
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Cantelo, William |
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Submitted to: Agricultural and Forest Entomology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 7/28/1999 Publication Date: N/A Citation: N/A Interpretive Summary: Earlier research has shown that placing 5-10 young of certain predatory stink bugs per potato plant can control the Colorado potato beetle (CPB). This level of predator release (augmentation) translates to about 50,000 predators per acre which, if the predators must be raised in commercial insectaries, makes this method of biological control economically impractical. The manuscript reports a method to use the chemical attractan (pheromone) for the predatory spined soldier bug (SSB), Podisus maculiventris (Say) (Heteroptera: Pentatomidae: Asopinae), to catch enough wild adults during 2-3 weeks in early spring to produce 400,000 to 1.6 million offspring. This method was tested in a 3-year project to use SSBs for biological suppression of the CPB. The first two years of the study showed that sufficient predators could be produced by pheromone- based technology to control the CPB on a larger scale than previously attempted. In the third year, wild SSBs were transferred directly from pheromone traps to mid-plot nursery cages having a mesh size chosen to retain the adult predators but allow their offspring to escape. This method was much less labor-intensive, and resulted in significantly improved potato yield. Trapping SSB adults in the spring also protects them from parasites that use the pheromone to facilitate host-finding. The compatibility of pheromone-mediated predator augmentation/conservation with implementation of transgenic plants, imidacloprid insecticide, and other biocontrol methods is discussed. This technology will benefit producers of biocontrol agents, gardeners and other commercial growers seeking alternatives to insecticides. Technical Abstract: Hardware and protocols were tested to enable individual growers and insectary operators to mass-produce predatory spined soldier bugs (SSBs), Podisus maculiventris (Say) (Heteroptera: Pentatomidae: Asopinae), for augmentative biological control. Using pheromone-based technology, an average of 1775 female SSBs (potentially 400,000 to 1.6 million offspring) were captured each year during 2-3 weeks in early spring. Data for the first two years of a 3-year project to use P. maculiventris for biological suppression of the Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), verified earlier research showing that augmentation of SSB (~5 nymphs/plant) can significantly suppress CPB infestations. In the third year, wild SSBs were transferred directly from pheromone traps to mid-plot nursery cages having a mesh size chosen to retain the adult predators but allow their offspring to escape. Pheromone dispensers were placed peripherally to promote dispersal of young predators and immigration of new wild spined soldier bug adults. Pheromone-mediated augmentation using porous nursery cages and pheromone dispensers was less labor- intensive than earlier methods, and resulted in significantly improved potato yield. Trapping P. maculiventris adults early in the spring protects them from parasitization by tachinid flies and scelionid wasps that use the pheromone to facilitate host-finding. The compatibility of pheromone-mediated predator augmentation/conservation with implementation of transgenic plants, imidacloprid insecticide, and other biocontrol methods is discussed. |
