Trap crop

A trap crop is a plant that attracts agricultural pests, usually insects, away from nearby harvested crops. This form of companion planting can save a main crop from decimation by pests with reduced use of artificial pesticides. A trap crop is used for attracting the insect and pests away from a target crop field or individual crop plants within a field. Many trap crops have successfully diverted pests from focal crops in small scale greenhouse, garden and field experiments; a small portion of these plants have been shown to reduce pest damage at larger commercial scales. A common explanation for reported trap cropping failures, is that attractive trap plants only protect nearby plants if the insects do not move back into the target crop. In a review of 100 trap cropping examples in 2006, only 10 trap crops were classified as successful at a commercial scale, and in all successful cases, trap cropping was supplemented with management practices that specifically limited insect dispersal from the trap crop back into the target crop. Quantitative models of pests moving between trap and main crops suggest that in the absence of such methods a substantial proportion of the landscape has to be dedicated to the trap crop, limiting the feasibility such a strategy if growers are not willing to sacrifice that much space to unharvested trap plants. In such cases optimal trap crop allocations can be up to roughly 30 percent of the field.