Biological Control in a High-Value Native Crop: Status, Opportunities, and Constraints in Cranberry

Abstract

<i>The American cranberry</i>, Vaccinium macrocarpon <i>Aiton, is a native North American plant that has become a cultivated crop in the northeastern and northwestern United States. Wisconsin, and Canada. The culture of commercial cranberry is unique, and the value of the crop is very high. The pest complex includes both direct and indirect pests, and all parts of the plant are subject to attack. Lepidoptera dominate as pests; others include scale insects, root and foliage-feeding Coleoptera, a cecidomyiid midge that kills the apical meristem, and, in the eastern United States, a spider mite. Most of these pests are indigenous and many have a substantial natural enemy complex which is reviewed, with most of our knowledge coming from Massachusetts and New Jersey. Current biological control practices include the use of</i> Bacillus thuringiensis <i>Berliner sprays for foliar Lepidoptera and insect parasitic nematodes for root-feeding Lepidoptera and Coleoptera. Other augmentation approaches to biological control also may exist, but need field evaluation. Importation biological control has not been attempted, but possible options for moving natural enemies within North America are discussed. This will not be practical until there is a better knowledge of the indigenous natural enemy fauna in Wisconsin and the Pacific Northwest. The cranberry industry has widely adopted IPM practices that have somewhat reduced the use of broad-spectrum insecticides, which probably has contributed to the conservation of natural enemies. Other potential conservation practices that involve habitat management also are discussed. Cranberry production and the pest complex of the crop provide both constraints and opportunities to increased implementation of biological control; these are discussed. It may be possible for biological control to provide the foundation of a cranberry IPM program that relies more on ecologically based methods rather than broad-spectrum insecticides, but considerable research will be necessary to move in this direction</i>.