Abstract:

Seventy-six imlates from root-knot nematodes(Meloidogyne spp.)eggs and adults were tested on water agar for the parasitism to eggs of M. Incognita. There was substantial variability in parasitism among isolates of the same species and the different species, which showed that this is a good method to test the parasitism of fungi to eggs. The parasitic rates of 10 of the 76 isolates were over 50%. As for Paecilomyces lilacinus, Verticillium chlamydosporium and V.lamellicola, the parasitism to eggs had no obvious difference among M. Incognita, M. Arenaria and M. Javanica, which indicated that these 3 fungal species may be effective agents for controI of root-knot nematodes. The experiment of the culture filtrates of parasitic fungi on the root-knot nematodes was firstly carried out. The result indicated that the culture filtrates of most parasitic fungi are highly toxic to juveniles. The culture filtrates of 24 of the 28 isolates in gliotoxin-fementation medium had high toxic to the juveniles of M. Incognita in 4 hours. Juveniles inactived rates were 56%~l00%. The culture filtrate of P. Lilacinus 54 resulted in 100%of the juveniles inactived in 4 hours, 100%mortality in 48 hours. The pot experiment of tomato seedlings in autoclaved soil showed that P. Lilacinus 54, 326 and F. Oxysporum 494 were more effective for control of M. Incognita, the root-knot index reduced 76.7%, 60.5%and 53.5%, respectively. All six isolates tested reduced 34.9%~93.5%of the number of galls.

Key words: Meloidogyne, Biological control, Parasitic fungi of root-knot nematodes