ABSTRACT

The goal of sustainable agricultural systems to manage weeds with no or very few chemicals relies partly on the use of biological controls to limit weed competition (Reganold, Papendick, and Parr, 1990). However, biological control as a single-tactic approach for controlling weeds in cultivated crops has not been as efficacious as those approaches involving herbicides and other cultural methods. The classic strategy of biological control in which host-weed-specific organisms are introduced into weed-infested sites and allowed to establish to population levels that regulate weed densities requires long periods (>1 year) for adequate control and is clearly unsuitable for use in annual crops. The inundative or mass-exposure strategy attempts to overwhelm a weed infestation with massive numbers of the biotic agent in order to attain weed control in the year of release and is the approach that has received the most attention in developing biological control for annual crops.