Flowering crabapples, Malus spp., are important small landscape trees in much of the United States and southern Canada. We evaluated 42 cultivars of Malus spp. for resistance to defoliation by Japanese beetles, Popillia japonica Newman, for 2 growing seasons and found marked and consistent variation in resistance. Defoliation caused by beetles ranged from 100 to <10% among cultivars at the same site. 'Radiant', 'Red Splendor', 'Royalty', 'Liset', 'Ruby Luster', and others were severely damaged, whereas M. baccata 'Jackii', 'Harvest Gold', and 'Jewel berry' were highly resistant in both years. Red - and purple-leaved cultivars, and those with reddish young leaves that mature to green, were generally fed upon more heavily than were cultivars with wholly green leaves. The rank order of cultivars in no-choice leaf disk assays was correlated with damage levels in the field. Longevity and fecundity of females were highest for beetles fed foliage from preferred cultivars. Possible mechanisms of resistance to P. japonica, and the relationship of our results to earlier studies of resistance of Malus spp. to diseases and other insect pests are discussed.
Document Type: Research Article
Publication date: August 1, 1995
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Journal of Economic Entomology is published bimonthly in February, April, June, August, October, and December. The journal publishes articles on the economic significance of insects and is divided into the following sections: apiculture & social insects; arthropods in relation to plant disease; forum; insecticide resistance and resistance management; ecotoxicology; biological and microbial control; ecology and behavior; sampling and biostatistics; household and structural insects; medical entomology; molecular entomology; veterinary entomology; forest entomology; horticultural entomology; field and forage crops, and small grains; stored-product; commodity treatment and quarantine entomology; and plant resistance. In addition to research papers, Journal of Economic Entomology publishes Letters to the Editor, interpretive articles in a Forum section, Short Communications, Rapid Communications, and Book Reviews.