APHIDS ON STRAWBERRY IN NOVA SCOTIA

Abstract

AbstractFifty-six species were recognized among 6886 aphids identified in 312 collections taken from strawberry plantations in Nova Scotia, 1961–1966. Forty-nine species were classed as errants and seven were classed as colonizers on strawberry. The most numerous colonizers were Rhodobium porosum (Sanderson) and Macrosiphum euphorbiae (Thomas), averaging 71 and 18.5% respectively of all the aphids identified. The other colonizers were Aphis forbesi Weed (1.4%), Aulacorthum solani (Kaltenbach) (1.0%). Myzus persicae (Sulzer) (1.0%), Chaetosiphon fragaefolii (Cockerell) (0.1%), C. minor (Forbes) (0.2%), and Chaetosiphon sp. (0.1%).Colonizers, mostly R. porosum, were observed on strawberry plantations from the time winter cover was removed in the spring until late in November when a winter cover was applied. Alate viviparous females were first observed during the second week of June on both old and new plantations and were most numerous during a period extending from the third week m June until nearly the end of August. Nymphs were first seen on new plantations when the first alatae were observed. Apterous viviparae reached near-maximum numbers early in July and were present, sometimes in relatively high number, until nearly the end of September. Sexuales began to appear late in September, reached peak numbers early in November, and were still present when observations were discontinued late in November. No consistent difference was noted in the numbers of aphids alighting on or colonizing plants of three different commercial strawberry varieties (Sparkle, Catskill, and Robinson). The amount of colonization was markedly greater on the commercial varieties than it was on Fragaria vesca L. (EMC). The significance of the results in relation to the control of aphid-borne viruses is discussed.