AbstractWe evaluated the effects of free-range chickens and geese on insect pests and weeds in an experimental, nonchemical agroecosystem consisting of an apple orchard with intercropped potatoes. The objective was to assess the potential of these domestic bird species as biological control agents. Four insect pests were studied: plum curculio, apple maggot, Japanese beetle, and Colorado potato beetle. Chickens fed on several potential crop pests, including Japanese beetle. Although Japanese beetles were less abundant on apple trees when chickens were present, the proportion of damaged fruit was not reduced. Furthermore, chickens did not affect weed abundance or crop productivity. In contrast, geese were effective weeders. Their activities reduced weed abundance and increased potato plant growth and yields compared with a minimally weeded control. In addition, the activities of geese indirectly reduced apple fruit damage by plum curculio and increased the proportion of pest-free fruit, possibly because removal of vegetation by the geese reduced humidity at the soil surface and therefore reduced the activity of plum curculio.
