ENHANCED PEST MANAGEMENT WITH COVER CROP MULCHES

Living and dead plant vegetation on the surface of soils can provide opportunities for regulating pest populations in no-tillage production systems. Cover crops generate substantial quantities of surface vegetation and residue that can be managed to enhance control of pests. Research at the Beltsville Agricultural Research Center has shown that weed germination and emergence is inhibited by high levels of cover crop mulch, that small-seeded annual weeds are particularly susceptible to suppression by mulches, and that herbicide use can be reduced when cover crops are incorporated into cropping systems. Growing mixtures of legume and cereal cover crops is a particularly effective way to produce large quantities of cover crop residue for weed suppression. Mulches with a high surface area-to-soil area ratio and a low amount of internal empty space are most highly correlated with inhibition of weed emergence. Foliar diseases can be reduced by a cover crop mulch, primarily by preventing dispersal of pathogen propagules through splashing and/or wind-borne processes. Cover crops can suppress establishment of soil-inhabiting herbivores such as Colorado potato beetle by disrupting emergence and migration behavior. Reduction of weed and pest populations by cover crops has reduced or eliminated crop yield loss caused by these organisms.