ABSTRACT
Crop residues affect pest populations and pest control either directly or through associated soil tillage. Because many pests and pest control techniques respond uniquely to crop residue levels and/or tillage, few definitive principles exist regarding pest management and crop residues. Although the individual effects of tillage and residue on pests generally have not been separated, crop residue levels typically are a function of soil tillage. Emerging generalizations regarding tillage systems and weed species are as follows: annual grass and perennial weeds tend to increase in importance in reduced tillage systems, relatively large-seeded broadleaf weeds tend to have higher densities in moldboard plow, and small-seeded broadleaf weeds appear highly individualistic in their adaptations to tillage systems. Crop residues may affect herbicide efficacy directly by intercepting the chemical before it reaches soil or contacts weed seedlings. However, the net effect of crop residue on weed control is somewhat contradictory.
