Pymetrozine Causes a Nontarget Pest, the Colorado Potato Beetle (Coleoptera: Chrysomelidae), to Leave Potato Plants

• Published in: Journal of economic entomology Vol. 101; no. 1; pp. 74 - 80
• Main Authors: Chang, G. C, Snyder, W. E
• Format: Journal Article
• Language: English
• Published: Lanham, MD Entomological Society of America 01-02-2008
• Subjects: Animals; aphicide; aphicides; Behavior, Animal - drug effects; Biological and medical sciences; Biological Assay - veterinary; Coleoptera - physiology; Colorado; Control; dispersal behavior; Ecology and Behavior; Fundamental and applied biological sciences. Psychology; Generalities; Insecta; Insecticides - pharmacology; Invertebrates; larvae; Leptinotarsa decemlineata; nontarget organisms; Phytopathology. Animal pests. Plant and forest protection; population density; potatoes; Protozoa. Invertebrates; pymetrozine; Random Allocation; Solanum tuberosum; Solanum tuberosum - parasitology; Triazines - pharmacology; Washington; Chrysomelidae; Insecticide; Coleoptera; Solanum tuberosum; Insecta; Pesticides; Systemic; aphicide; Pyridine derivatives; Pest; Leptinotarsa decemlineata; Arthropoda; Dicotyledones; Angiospermae; Spermatophyta; Tuber plant; Solanaceae; Invertebrata
• ISSN: 0022-0493; 1938-291X
• DOI: 10.1603/0022-0493%282008%29101%5B74%3APCANPT%5D2.0.CO%3B2

Pymetrozine is a selective insecticide that targets aphids. Published assessments of the effects of pymetrozine on nontarget organisms focus mainly on predatory insects, and they rarely indicate toxicity. In a laboratory bioassay, survival of Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), larvae was not affected by pymetrozine exposure. We subsequently used pymetrozine to implement low-aphid-density treatments in a field experiment that involved separate manipulations of Colorado potato beetle density. Unexpectedly, the addition of Colorado potato beetle adults and eggs did not increase the densities of Colorado potato beetle larvae in plots that were sprayed with pymetrozine (applied with water and an adjuvant). In control plots sprayed with water and adjuvant (without pymetrozine), addition of Colorado potato beetles increased densities of their larvae. Data collected on a smaller scale suggest that a behavioral mechanism underlies the population-level pattern: Colorado potato beetle larvae become more active and are less likely to remain on a host plant after exposure to pymetrozine. Thus, potato, Solanum tuberosum L., growers who use pymetrozine against aphids also might benefit in terms of Colorado potato beetle control.