Abstract

Pest control poses a challenge to all gardeners, especially those wishing to use organic practices. We examined the potential use of Polistes paper wasps as a bio-control agent in the organic backyard garden. Polistes are important predatory insects which may potentially consume thousands of soft bodied pest insects per season. We planted 8 garden plots with leaf lettuce, cabbage, pole beans and tomatoes. In 4 experimental plots, we established 8 Polistes dominulus nests, while in the remaining control plots we did not establish wasp nests. We measured the abundance of pest insects, the extent of damage from insect pests, and the weight of the plants at harvest. We did not observe any statistically significant differences between the experimental and control plots, however, we did find that cabbage plants from plots with more wasps had less insect damage than plants from plots with fewer wasps. Although our study appears to demonstrate that Polistes wasps were not effective in controlling pests, the observation that wasp number influenced damage levels in cabbage suggests that, at least for that crop, there is a density of wasps that can be effective.