Agrobiodiversity influence on pests and their natural enemies in agroecosystems

Obviously vegetational diversity strongly influences insect diversity, a fact which is exploited in traditional polyculture farming systems; crop diversity in time and space reduces the incidence of insect pests. On the other hand monoculture farming systems enhance insect pest problems. Two main hypotheses have been formulated to account for this: natural enemy enhancement and resource concentration. We analyze here the influence of vegetational diversity in farming systems on beneficial and pest insects, considering both crops and landscape scales, with particular reference to generalist predators.