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ARS Home » Northeast Area » Kearneysville, West Virginia » Appalachian Fruit Research Laboratory » Innovative Fruit Production, Improvement, and Protection » Research » Publications at this Location » Publication #132850
Title: ROLE OF THE APHID PREDATOR GUILDIN REGULATING SPIREA APHID POPULATIONS ON APPLE IN WEST VIRGINIA, USA

Author
item Brown, Mark

Submitted to: Ecological Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/21/2003
Publication Date: 12/4/2003
Citation: BROWN, M.W. ROLE OF THE APHID PREDATOR GUILDIN REGULATING SPIREA APHID POPULATIONS ON APPLE IN WEST VIRGINIA, USA. ECOLOGICAL ENTOMOLOGY.

Interpretive Summary: Biological control, the control of insect pests with beneficial insects, is a key ingredient in a sustainable pest management program. The spirea aphid is a pest of apple in the eastern U.S. requiring routine sampling to determine aphid numbers which provide a basis for applications of insecticides to keep aphids from reducing yield of apples. This study was conducted to evaluate the naturally occurring biological control of spirea aphid in West Virginia, especially in light of the recent introduction of the Asian lady beetle (Harmonia axyridis) into the region. This beetle is considered to be an effective predator of spirea aphid. Laboratory experiments, field sampling, and caged field experiments over 3 years documented 14 species of predators feeding on spirea aphid on apple in West Virginia. Aphid predators did control spirea aphid populations on apple. The Asian lady beetle was the most abundant predator and was responsible for providing control of the spirea aphid. Pest management specialists and extension agents will use these results in managing aphids on apple. Biological control researchers will use the results of this study as a model of how to evaluate predation of a pest in the field by a large number of predators.

Technical Abstract: The interactions between spirea aphid and its predators on apple were studied to identify which, if any, predators were important in regulating aphid populations. Random and non-random sampling from apple orchards in West Virginia, USA, sentinel aphid colonies, laboratory feeding studies and predator exclusion studies were used. Aphidoletes aphidimyza (Diptera: Cecidomyiidae), chrysopids, (Neuroptera: Chrysopidae), Harmonia axyridis (Coleoptera: Coccinellidae), and Orius insidiosus (Hemiptera: Anthocoridae) were the most abundant predators associated with spirea aphid colonies on apple. Parasitoids were all but absent from spirea aphid colonies. Abundance of all the predators was density dependent on aphid population size, responding more to aphid populations at the orchard scale than to tree or individual colony scales. Aphidoletes aphidimyza, Orius insidiosus (Hemiptera: Anthocoridae), chrysopids, and syrphids (Diptera) had the greatest degree of density dependence, and spiders had an inverse density dependence on aphid populations. Exclusion of predators with both cages and insecticides produced significantly higher aphid populations. Harmonia axyridis had the strongest regulating influence on spirea aphid populations on apple because of its high abundance, synchrony with aphid populations, and high impact rating.