Effects of the insecticides methoxyfenozide and cypermethrin on non-target arthropods: a field experiment

The adverse effect of pesticides on non-target organisms and the environment is an issue of great social concern. Currently, there are a variety of availably insecticides, which are claimed to be safer for beneficial organisms than broad-spectrum insecticides. We conducted a field experiment to compare the effect of applications of methoxyfenozide (an insect growth regulator) and cypermethrin (a conventional insecticide) on the arthropod community in a commercial willow plantation. We used a one-way Anova design with insecticide as the treatment factor, each individual tree as the experimental unit, and the number of dead arthropods collected per sampling unit as the response variable. Results showed that the number of dead arthropods collected 72 h after treatment with methoxyfenozide (1274 individuals) was 66% lower than that collected underneath cypermethrin-treated trees (3408 individuals). The only groups not recorded from boxes places underneath methoxyfenozide-treated trees, but yes underneath cypermethrin-treated trees, were Dyctioptera, Pseudoscorpionida and Isopoda. Methoxyfenozide was lethal to a lower number of families of dipterans, coleopterans and hymenopterans than the cypermethrin during the first 72 h after treatment. The number of taxonomic groups and abundance of dead predators, herbivores and parasitoids was also lower in methoxyfenozide than in cypermethrin-treated trees. Our results obtained from a field experiment suggest that methoxyfenozide provides a less toxic alternative for control of pests in willow plantations due to a reduced effect on non-target organisms. Fil: Loetti, María Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina Fil: Bellocq, Maria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina