Woodpeckers and the Southern Pine Beetle

James C. Kroll - Associate Professor of Forest Wildlife, Stephen F. Austin State University, Nacogdoches, Tex.
Richard N. Connor - Research Wildlife Biologist, Forest Service, U.S. Department of Agriculture, Southern Forest Experiment Station, Wildlife Habitat and Silviculture Labratory, Nacogdoches.
Robert R. Fleet - Research Associate in Forest Wildlife, Stephen F. Austin State University.

U.S.D.A. Combined Forest Pest Research and Development Program Agriculture Handbook No. 564

In 1974 the U.S. Department of Agriculture initiated the Combined Forest Pest Research and Development Program, an interagency effort that concentrated on the Douglas-fir tussock moth in the West, on the southern pine beetle in the South, and on the gypsy moth in the Northeast. The work reported in this publication was funded in part by the Program. This handbook is one in a series on the southern pine beetle.

Life Cycle of SPB

Since woodpecker prediction is closely related to SPB life stages, we will briefly review what is known about the SPB life cycle. Beetles overwinter within trees attacked the previous fall. In spring, most adults seek host trees susceptible to beetle attack as a result of disease, lightening strike, or other injury. Females then burrow into the tree and produce substances (pheromones) that attract more males and females. Mass attacks by large numbers of beetles usually follow. The mated pair burrow through the bark and into the cambium, where eggs are deposited in individual niches. Initial attack is at 10-15 ft above ground. The tree is later attacked above and below this region, but beetles remain most abundant at this level, where larvae mature earlier than those at other levels in the tree.

Larvae pupate in the outer bark. Fully developed, emerging beetles or "brood adults," as well as reemerging parent adults, may attack adjacent trees or fly to other susceptible trees. Maturation from egg to adult may take as little as 4 weeks in summer or as long as 3 months in winter. In the Deep South, seven to eight overlapping generations may occur in a single year.

Although SPB attack all species of southern pines, the insect survives and reproduces best in loblolly (Pinus taeda L.) and shortleaf (P. echinata Mill.) pines.

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