Ozone-treated plants of 5 strains of alfalfa, Medicago sativa L., were compared with untreated plants for resistance to Acyrthosiphon pisum (Harris). Treated plants were exposed to 20 pphm ozone for 4 h at 26°C, 92% RH, and an illumination of 21.5 KLx (2000 ft-c). After 48 h, they were scored on a numerical scale for ozone injury. Ozone-treated and untreated plants were then evaluated for pea aphid resistance by caging 4 adult females on each plant for 7 days and then recording adult survival, living nymphs, and dead nymphs. Higher levels of ozone resistance were confirmed in alfalfa entries that had previous cycles of selection in the greenhouse for air pollutant resistance. The variety 'Team' and the experimental population MSA-CW3An3, 2 of the 3 entries with higher levels of ozone resistance, also displayed higher levels of pea aphid resistance. MSBCW5An3 also was resistant to ozone but not to the pea aphid. The varieties 'Mesa-Sirsa' and Williamsburg' were susceptible to both ozone and the pea aphid. Ozone injury had little or no effect on alfalfa resistance to pea aphids as expressed by numbers of surviving adults, living nymphS, and dead nymphs.
Document Type: Research Article
Publication date: April 1, 1978
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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.