Infestations of the navel orangeworm, Amyelois transitella (Walker) in six central California 'Nonpareil' almond orchards were studied for 12-13 yr (1978-1991) to determine the effect of imported parasitoids on host abundance. A decline in the average density of navel orangewornl to <0.5% in late summer as measured by percentage of attacked almonds was observed in five orchards where insecticides were not applied during the growing season. K-value analyses indicated a significant regulation of the navel orangeworm population by Goniozus legneri Cordh during the first generation on almonds after hull split. A slight increase in navel orangeworm abundance was observed in one orchard in 1986, after insecticide applications. Significant (but low) correlations existed between higher yields of edible almonds and lower navel orangeworm densities. No significant correlations were found between total rejected almonds and numbers of the peach twig borer, Anarsia lineatella Zeller, or ant damage. An integrated pest management program may be possible for soft-shelled almonds by retaining sufficient holdover almonds during winter for host-parasitoid reproduction during the spring, and by targeting other arthropod pests (e.g˜,peach twig borer and phytophagous mites) with controls that are nondisruptive to navel orangeworm parasitoids.
Document Type: Research Article
Publication date: December 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.