Ant exclusion barriers were constructed in two Chelan County, Wash., pear orchards to prevent ants from foraging in pear tree canopies. Orchard 1 had a naturally occurring high density of Formica neoclara (Emery), a predatory ant. Ants were introduced into Orchard 2 in August 1987. Exclusion studies were carried out in Orchard 1 during 1987-1989 and in Orchard 2 during 1988-1989. Each year, adult and immature pear psylla population densities in selected trees were estimated by beating tray and leaf sampling. During most years, adult and immature pear psylla, Cacopsylla pyricola (Foerster), population densities were significantly higher in ant-excluded trees. In Orchard 2, densities of immature psylla were significantly higher before ant introduction than after introduction on trees without exclusion barriers. Psylla densities did not differ from postant introduction densities in ant-excluded trees. This study showed that predatory ants can significantly reduce pear psylla population densities.
Document Type: Research Article
Publication date: February 1, 1992
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Journal of Economic Entomology is published bimonthly in February, April, June, August, October, and December. The journal publishes articles on the economic significance of insects and is divided into the following sections: apiculture & social insects; arthropods in relation to plant disease; forum; insecticide resistance and resistance management; ecotoxicology; biological and microbial control; ecology and behavior; sampling and biostatistics; household and structural insects; medical entomology; molecular entomology; veterinary entomology; forest entomology; horticultural entomology; field and forage crops, and small grains; stored-product; commodity treatment and quarantine entomology; and plant resistance. In addition to research papers, Journal of Economic Entomology publishes Letters to the Editor, interpretive articles in a Forum section, Short Communications, Rapid Communications, and Book Reviews.