Submitted to: The Canadian Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/13/2012
Publication Date: 10/3/2012
Citation: Horton, D.R., Miliczky, E., Jones, V.P., Baker, C.C., Unruh, T.R. 2012. Diversity and phenology of the generalist predator community in apple orchards of Central Washington State (insecta, araneae). The Canadian Entomologist. 144:691-710. Interpretive Summary: Effective use of biological control in apple orchards requires information on when (seasonally) natural enemies of pests are present in orchards. Scientists with USDA-ARS, Yakima Agricultural Research Laboratory, Wapato, WA in cooperation with scientists at Washington State University, Wenatchee, WA collected predatory insects and spiders every 3 to 7 days over the duration of the growing season from orchards in central and south-central Washington state. They found that species of predators differed substantially in seasonal timing of presence in orchards, and that seasonal presence of the most common and important species was predictable based upon calendar date. These results will allow apple growers to better predict when certain important natural enemies are likely to be present in their orchards, which in turn will allow growers to time insecticide sprays to avoid critical time periods.
Technical Abstract: Predatory insects and spiders were collected from apple orchards in two geographic regions of Central Washington State to assess seasonal phenology and diversity of the generalist predator community. Arthropods were collected from orchard canopy every 3-7 d over two growing seasons (March-October) at seven organic and two unmanaged orchards. Over 35,000 specimens and 80 identified species of spiders (Araneae), ladybeetles (Coleoptera: Coccinellidae), lacewings (Neuroptera), and predatory true bugs (Homoptera: Hemiptera: Heteroptera) were collected. Composition of insect and spider communities differed between the two geographic regions. Indicator species analysis identified several species which had a significant association with one of the two regions. Counts of common taxa were examined on a calendar date basis to determine seasonal phenology of adult and immature stages. We observed substantial differences among taxa in number of generations, seasonal timing of first appearance in orchards, life history stage which overwinters, and seasonal occurrence of the adult and immature life stages in orchards. Understanding seasonal phenology of natural enemies in orchards is a core requirement in developing IPM programs for apple pests, and results of this study provide this information for the generalist predator community of orchards in the Pacific Northwest.