ABSTRACT
One important form of diversication is the deliberate inclusion of certain weeds in the agroecosystem (Chapter 16 of Agroecology: The Ecology of Sustainable Food Systems). The strategic placement of weeds in an agroecosystem can affect the ability of pests to nd and colonize a crop, or it can attract benecial insects that can help control pests. When weeds are used as borders around a crop, the concepts of island biogeography (Chapter 17 of Agroecology: The Ecology of Sustainable Food Systems) can come into play. The weed may act as a dispersional barrier around the crop “island.” As a barrier, the weedy border may “trap” pests or shield the crop from detection and colonization by pests. Or the weed border may itself act as an island of suitable habitat for benecial insects, which may disperse outward into the crop to prey on pests.
