PARASITISM OF NEMATODES BY THE FUNGUS HIRSUTELLA-RHOSSILIENSIS AS AFFECTED BY CERTAIN ORGANIC AMENDMENTS

Experiments were conducted to determine whether the addition of organi c matter to soil increased numbers of bacterivorous nematodes and para sitic activity of the nematophagous fungus Hirsutella rhossiliensis. I n a peach orchard on loamy sand, parasitism of the plant-parasitic nem atode Criconemella xenoplax by H. rhossiliensis was slightly suppresse d and numbers of C. xenoplax were not affected by addition of 73 metri c tons of composted chicken manure/ha. In the laboratory, numbers of b acterivorous nematodes (especially Acrobeloides spp.) and fungivorous nematodes increased but parasitism of nematodes by H. rhossiliensis us ually decreased with addition of wheat straw or composted cow manure t o a loamy sand naturally infested with H. rhossiliensis. These results do not support the hypothesis that organic amendments will enhance pa rasitism of nematodes by H. rhossiliensis.