ISOLATION AND SCREENING OF FUNGI FOR THE BIOLOGICAL-CONTROL OF POTATO CYST NEMATODES

Using observation chambers, fungal parasites of young potato cyst nematode females growing on potato roots were isolated from fourteen field soils. Cylindrocarpon destructans was the most commonly occurring fungus. Eight of the ten fungi selected for screening gave significant control of the nematode when cultured on milled wheat straw and added to soil. Methods of culturing influenced the amount of control achieved, but three fungi, C, destructans, Fusarium oxysporum and F. sambucinum, were particularly effective in decreasing nematode populations. The problems of selecting suitable control treatments, and the advantages and disadvantages of two different screening methods, are discussed.