Treesearch

The nitidulid Stelidota ferruginea Reitter was reared from damaged acorns of laurel oak, Quercus laurifolia Michx., and live oak, Q. virginiana Mill., collected in Sarasota County, Florida. This sap beetle has been reared in the laboratory solely on northern red oak, Q. rubra, acorns for over 3 years (27 + generations) and can breed in viable or nonviable acorns. In the laboratory, S. ferruginea can develop in the seeds of several species of trees. New information on the biology of S. ferruginea is presented.

Appalachian hardwood stands in West Virginia were managed for 30 or more years using single-tree selection regeneration practices. Stand yield data suggest that current stand growth will provide economical harvest cuts for several future cutting cycles. This case study indicates that the single-tree selection practice has potential for landowners who want to maintain continuous overstory cover and are willing to accept the gradual species shift to the more shade-tolerant species.

Damaged germinating northern red oak, Quercus rubra L., acorns in pitfall traps were significantly more attractive to two species of acorn insects than undamaged germinating acorns. Significantly more adults of the weevil Conotrachelus posticatus ohe em an and the sap beetle Stelidota octomaculata (Say) were caught in traps containing germinating acorns cut into halves than in traps containing uncut germinating acorns. Larvae of the acorn moth Valentinia glandulella (Riley) also preferred damaged over undamaged acorns, but few larvae were caught and the results were not analyzed.

Examines the effect of sale characteristics and number of bidders on sale value for timber sold by sealed-bid auction on the Green Mountain National Forest in Vermont. As anticipated from theory and previous empirical studies, increasing the number of bidders tended to increase the winning-bid value for the timber auctions studied. Efforts made to ensure that a timber sale offering received at least one qualified bid had a greater impact on sales revenue than efforts made to increase high-bid value. In designing sales, managers should avoid setting appraisal value too high in relation to...

For roughly 200 years it was assumed that trap trees attracted the bark beetle Ips typographus by means of specific chemical compounds produced by the tree. After the aggregation pheromone was discovered, the importance of tree volatiles was at first more or less totally denied (Vité 1980). Since Johann succeeded in proving that the combination of pheromone plus tree is, at times, considerably more attractive than the combination of Pheroprax plus plastic trap (Bombosch et al. 1982, Johann 1986a, 1986b), more attention has been paid to the tree even by pheromone supporters (Bakke 1985,...

The southern pine bark beetle guild consists of many species, the most economically significant of which are the five scolytid species, Dendructonus frontalis Zimmermann, D. terebrans (Olivier), Ips calligraphus (Germar), I. avulses (Eichhoff), and I. grandicollis (Eichhoff). All five species coexist in pine forests across the southern and southeastern United States. When the species cohabit in the same host tree each usually occupies a distinct niche. However, the area occupied by one species generally overlaps with that occupied by another (Fig. 1) (Birch and Svihra 1979, Dixon and Payne...

Identification of aggregation pheromones and field experiments using synthetic components have given scientists a better understanding of the behavior of many bark beetles. They have also yielded more effective weapons with which to control outbreaks of aggressive pest species. Synthetic pheromone components are commercially available for control of many species (Borden 1985) and are used in forestry practice in several areas of the world (Vité and Francke 1985). The pheromone may be used as part of an integrated pest management program: for mass trapping, for monitoring of beetle populatio...

One of the best studies of a xylophage consortium is the case of larch insects by Isaev and Girs (1975). In their book, a basic theory was presented about host responses to xylophagous insects injury. According to their concept of "sliding resistance," different trunk-infesting insect species have different reactions to the tree's defenses and invade the tree successively depending on the stage of its decline or dieback With regard to the general tree status, groups of invaders were identified by the authors: 1) primary species invading living trees whose resistance may increase back to...

More than 30 species of beetles have been identified/documented as pine borers in Japan, the majority of them belonging to the Curculionidae, Cerambycidae, and Scolytidae. The density of their populations is controlled primarily by food supply. Although most of them are secondary pests which cannot attack healthy trees, an epidemic of pine wilt disease caused by the pine wood nematode, Bursaphelenchus xylophilus, has guaranteed them a continuously sufficient food supply. This paper discusses the results of an experiment to study seasonal and spatial changes in the structure of the subcortic...

Insects not only use plants for food and habitat; they also change plant populations by influencing their structure and dynamics. This influence is evidenced in the alteration of the spatial structure of a stand. The fir sawyer, Monochamus urussovi Fisch. (Coleoptera: Cerambycidae), is the most abundant xylophagous insect injuring siberian fir, Abies sibirica Ledeb. It dominates both in outbreak and non-outbreak areas. The beetles influence the structure and dynamics of fir stands by damaging tree crowns during adult feeding. At high population density this damage eventually determines the...