Efficacy of nematophagous fungi for the biocontrol of tomato root-knot nematode Meloidogyne incognita, Chitwood and potato cyst nematode, Globodera rostochiensis, Woll. in the Philippines

Laboratory assay indicated that the other isolates of Paecilomyces lilacinus and other nematophagous fungi tested were capable of infecting and parasitizing Meloidogyne incognita eggs and larvae inside the eggs. The fungus isolates significantly reduced egg hatching resulting to high percent mortality of the root-knot larvae compared with the untreated check. Compared with the nematicide treatment the effect was within the range or sometimes better. All the isolates grew and sporulated well on all the pH level 3-11 at optimum temperature of 20-30 deg C. The best sporulation occurred at 30 deg C but poor growth at 10 deg C and 40 deg C. In general, continuous darkness favored the growth and sporulation of the fungi. The fungus isolates grew abundantly in mashed potato, rice bran, sorghum, and corn grits substrates. It grew moderately on water lily. P. lilacinus growth was suppressed or inhibited with dual or triple cultures with other fungi. The isolates tested under greenhouse conditions were effective against root-knot nematode infection resulting to low gall indices, gall number and egg mass production. Use of three levels of spore density of each isolate also significantly reduced the nematode infection in tomato in varying degrees of effectiveness but comparable with nematicide treatment. P. lilacinus isolates and the other nematophagous fungi tested in Bonglo, Atok, Benguet [Philippines] were all effective against the potato cyst nematode significantly reducing nematode population resulting in considerable increase in tuber yield. Levels of spore density is generally proportional to degree of effectiveness, i.e. the higher the spore density, the higher the percentage nematode control. The nematophagous fungi tested were readily recovered from the soil in the treated field. The reisolated fungi were identical to that of the original cultures.