Treesearch

Autographa californica nuclear polyhedrosis virus (AcNPV) the prototypic group A baculovirus, has the widest reported host range of the baculoviruses and is considered to be one of the most virulent baculoviruses studied. The gypsy moth Lymantria dispar is not considered a natural host of AcNPV, however. To determine the factors regulating AcNPV restriction in L. dispar, in vivo and in vitro studies on AcNPV replication in gypsy moth cells have been initiated.

General larval predators of low-density gypsy moth, Lymantria dispar (L.), populations have been assessed by exposing caterpillars tethered by threads. Most mortality occurred on tree trunks and in leaf litter.

Deferment cutting is a regeneration practice that resembles a seed-tree or shelterwood cutting. The difference is that residual trees are not cut when the reproduction becomes established. Instead, residual trees are left until new reproduction matures to sawtimber size, and another regeneration cut is the silvicultural objective. Hence, with deferment cutting specific residual trees are left for a long period (Smith et al. 1989).

Interest in applying group selection in upland hardwoods has grown in recent years, primarily in response to public opposition to the aesthetic effects of clearcutting. Critics suggest that an uneven-aged silvicultural practice such as group selection might be a suitable compromise--drastically reducing negative visual effects of harvesting trees while continuing to utilize the timber resource.

The bioassay of 260 strains of Bacillus thuringiensis (Bt) and 70 commercial preparations show that regression coefficient estimates may be as critical as LC5O estimates when evaluating them for future consideration.

The "Abington" isolate of the nuclear polyhedrosis virus (NPV) of the gypsy moth (Lymantria dispar L.) was compared with a formulation of Gypchek against a natural gypsy moth population in the Swallow Falls State Forest in Garrett County, MD.

Thirty-one papers and three posters on the systematics, biology, behavior and management of Thysanoptera, with particular reference to Taeniothrips inconsequens (Uzel), pear thrips, presented at an international conference in Burlington, Vermont.

Acari of the family Phytoseiidae are important predators of spider mites. Since the taxonomic treatises of Nesbitt (1951) and later by Chant (1959), over 1000 described taxa have been listed by Moraes et al. (1986).

Greenhouse thrips, Heliothrips haemorrhoidalis (Bouche), on avocado in California, is another case, like pear thrips, of a species being present for many decades but only recently increasing to major pest status. Damaging infestations, previously occurring only sporadically and mainly in areas within a few kilometers of the coast, now are common in the interior districts of Ventura and San Diego Counties in southern California. Greenhouse thrips causes scarring of fruit, mainly on the Hass variety, reducing its market value. The problem has brought about an increased use of insecticides by...

Thrips have been considered as both target pests and control agents in biological control. The main emphasis of this paper concerns the natural enemies of thrips and an appraisal of the potential for biological control of the pear thrips on sugar maple in the northeastern United States. Previous attempts at biological control of thrips pests have been confined to the Caribbean and Hawaii and have made use of eulophid larval parasitoids and anthocorid predators as control agents. A review of the literature indicates that while these two groups often figure most strongly in natural enemy...