The larvae of the European pine sawfly, Neodiprion surtifer (Geoffroy), injure their hosts by old-growth defoliation, debarking, and current-shoot girdling. Defoliation is undoubtedly responsible for nearly all the growth loss. Both height growth and radial growth are inversely related to sawfly population levels, but radial growth is affected most, especially at higher population Ievels. The extent of growth loss is a function of the amount and the rate of foliage removed. Damage after 2 seasons depends upon the quantity of foliage available and removed in both seasons. Trees are seldom without foliage because some new-growth needles appear before all the old-growth needles can be consumed. Even at very heavy population levels defoliation seldom exceeds 90% when old and new foliage arc considered together. Since new foliage continues to grow after the sawflies leave the host, the trees "recover" later in the season. Host mortality was not observed even after 3 years of severe defoliation.
Document Type: Research Article
Publication date: October 1, 1966
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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.