Survey of Potential Aphid Vectors of Potato (Solarium tuberosum L.) Virus Diseases in the Matanuska Valley, Alaska

ABSTRACT

Aphids were surveyed in bedding plant greenhouses and commercial potato fields. Composition of aphids infesting bedding plants was 88.8%, 8.2%, and 3%, respectively, for Myzus persicae (Sulzer), Macrosiphum euphorbiae (Thomas) complex, and Aphis gossypii Glover. Percent plant infestations were dahlia (Dahlia sp.), 33.5%; pepper (Capsicum annuum L.), 6.7%; pansy (Viola × wittrockiana), 4.3%; marigold (Tagetes erectd), 1.6%; tomato (Lycopersicon esculentum Mill.), 1.3%; and petunia (Petunia × hybrida), 0.6%. Cabbage, snapdragon, and forget-me-not were not infested.

Tile trap pans placed in two potato fields captured 17 aphid species in one season. Five species or groups (Pemphigus sp., Lipaphis erysimi (Kaltenbach), Hayhurstia atriplicis (L.), Kakimia sp. and M. euphorbiae) comprised 73% of the aphids collected. Only M. euphorbiae and M. persicae reproduce in and formed colonies in pota-to fields. Macrosiphum euphorbiae was attacked by the fungus Pandora neoaphidis (Remaudiere' and Hennebert) and the wasp parasitoid Aphidius nigripes Ashmead.

Aphid population densities were never high enough to pose a threat to potato yields, but were abundant enough to transmit potato leaf roll virus. Increased seed potato production in this area would require aphid management strategies.

KEYWORDS:

• Alaska
• potato
• Myzus persicae
• Macrosiphum euphorbiae
• aphid species survey