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Abstract
Two-hundred shoots contained within randomly selected locations from each of thirty-six coast live oak,
Quercus agrifolia, trees were sampled to determine the abundance and spatial distribution of acorns infested by the filbert weevil,
Curculio occidentis in northern California during 1989. The seasonal abundance of infested acorns was highest at 30 percent during mid-September. Overall, 25 percent of all acorns observed on sample trees revealed signs of boring insect activity. Slightly higher infestation rate of 38 percent was obtained from laboratory dissections of field collected acorns (n = 501). Of those acorns dissected in the laboratory found to contain insect larvae, 70 percent contained
C. occidentis and 30 percent contained the filbertworm,
Melissopus latiferreanus. Although acorns were numerous on the sunny side of the tree, infested acorns were more abundant on the shady side. The differential distribution of acorns spatially within trees, acorn survivorship, and the impact of insect and other animal acorn predators on acorn production are discussed.
Parent Publication
Citation
Lewis, Vernard R. 1991. The Temporal and Spatial Distribution of Filbert Weevil Infested Acorns in an Oak Woodland in Marin County, California. In: Standiford, Richard B., tech. coord. 1991. Proceedings of the symposium on oak woodlands and hardwood rangeland management; October 31 - November 2, 1990; Davis, California. Gen. Tech. Rep. PSW-GTR-126. Berkeley, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture; p. 156-160
