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United States Department of Agriculture

Agricultural Research Service

Research Project: Integrated Pest Management for Insect Pests of Horticultural Crops

Location: Horticultural Crops Research

Title: Location of the mechanism of resistance to Amphorophora agathonica (Hemiptera: Aphididae) in red raspberry

Authors
item Lightle, Danielle -
item Dossett, Michael -
item Backus, Elaine
item Lee, Jana

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 5, 2012
Publication Date: August 1, 2012
Citation: Lightle, D., Dossett, M., Backus, E.A., Lee, J.C. 2012. Location of the mechanism of resistance to Amphorophora agathonica (Hemiptera: Aphididae) in red raspberry. Journal of Economic Entomology. 105:1465-1470.

Interpretive Summary: The large American raspberry aphid is an important virus vector in red and black raspberries in North America. Host plant resistance in the form of a single dominant gene named Ag1 can help control virus diseases. However, the mechanism responsible for creating resistance is poorly understood. Aphid feeding was monitored using an Electrical Penetration Graph, where a mild electrical circuit is produced to study feeding behavior. Aphids feeding on a resistant red raspberry cultivar, 'Tulameen', were compared to a susceptible control, 'Vintage'. There were no differences in feeding behaviors performed by aphids as their mouthparts moved toward the phloem. Once in the phloem, aphids feeding on resistant plants spent significantly more time salivating than on susceptible plants and ingested significantly less phloem sap. This suggests a mechanism for resistance to raspberry aphid is located in the phloem. As a result, semi-persistent and persistent viruses are less likely to be acquired by aphids feeding on resistant plants.

Technical Abstract: The aphid Amphorophora agathonica Hottes is an important virus vector in red (Rubus idaeus L.) and black (Rubus occidentalis L.) raspberries in North America. Host plant resistance in the form of a single dominant gene named Ag1 has been relied upon to help control aphid-transmitted plant viruses; however, the mechanism of resistance is poorly understood. Aphid feeding was monitored using an electrical penetration graph (EPG) on the resistant red raspberry 'Tulameen' and compared with a susceptible control, 'Vintage'. There were no differences in pathway feeding behaviors of aphids as they moved toward the phloem. Once in the phloem, however, aphids feeding on resistant plants spent significantly more time salivating than on susceptible plants and ingested significantly less phloem sap. This suggests that a mechanism for resistance to A. agathonica is located in the phloem. Reduced ingestion of phloem may result in inefficient acquisition of viruses and is a likely explanation for the lack of aphid-transmitted viruses in plantings of resistant cultivars.

Last Modified: 8/29/2014
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