Yield Loss Relationships of Tobacco and Tomato Hornworms (Lepidoptera: Sphingidae) at Several Growth Stages of Maryland Tobacco
Authors: Kolodny-Hirsch, Douglas M.; Harrison, Floyd P.
Source: Journal of Economic Entomology, Volume 79, Number 3, June 1986 , pp. 731-735(5)
Publisher: Entomological Society of America
Abstract:Field studies were conducted during 1981 to determine pest density/yield loss relationships resulting from artificial infestations of the tobacco and tomato hornworms (THW), Manduca sexta (L.) and M. quinquemaculata (Haworth), at several growth stages of Maryland tobacco. Regression analysis showed that tobacco yields declined as the number of THW per plant or the percentage of infested plants increased. Data clearly showed that yield loss varied with date of infestation relative to plant phenology. Tobacco became more tolerant of THW infestations as it aged. Nonuniform infestations resulted in greater yield reduction than uniform infestations. Based on current cost of suppression and market value of Maryland tobacco, THW population levels capable of causing 1.8% yield loss would justify treatment. These data show that the economic injury levels for THW vary considerably with plant growth stage and distribution patterns of infestations, and that current static economic injury levels of 10 THW per 100 plants are generally too low.
Document Type: Research Article
Publication date: 1986-06-01
- 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.
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