Movement of potato root diffusate through soil.

Movement of potato root diffusate (PRD) through soil was examined by using the hatch of eggs from Globodera rostochiensis cysts as an indicator. Porous bags containing cysts were placed at increasing distances and depths from potato roots, whose growth was restricted by nylon mesh. Significantly greater hatch was observed up to 50 cm laterally away from potato roots, compared with hatch in fallow soil. Eight weeks after plant emergence, we detected a concentration gradient of PRD, as measured by egg hatch, that decreased with increasing lateral and vertical distance from the root zone. Egg hatch beyond 5 weeks after plant emergence was not attributed to PRD.