Efficacy of soil-applied pesticides

The soil-acting pesticides comprise many compounds with divergent biological activities. This chapter illustrates key ideas, principally by reference to research results for the widely used soil-acting nematicides aldicarb, oxamyl, and ethoprophos. It discusses simulation of pesticide movement in soils. Pesticides need to be formulated to assure ease of application. For spraying, it is necessary to mix the products quickly throughout a comparatively large volume of water. The sorption of a pesticide on soil reduces its availability to the target organism, both in the soil solution and the soil-gas phase. Weakly sorbed compounds usually exhibit little effect of sorption on efficacy, thus they are usable for a wide range of soils. The persistence of a pesticide in soil is increased by applying it as a granular formulation. The chapter also discusses efficacy of a pesticide in relation to exposure of pests to the pesticide over time.