The effect of several antagonistic fungi isolate on biological control of tea root lesion nematode (Pratylenchus loosi)

Currently, the management of the struggle against tea root lesion nematode (Pratylenchus loosi) based on biological control is one of the research priorities in tea product. In this research, after sampling the soil and root of tea bushes in tea cultivated areas included Guilan and Mazandaran provinces during the spring and summer of 2013, fungi were isolated from tea rhizosphere soil area. The fungi tested included Paecilomyces lilacinus (T1), P. lilacinus (N1, N3), Fusarium culmurom, Clonostachys rosea and Acremonium strictum. After identifying, purifying of strains and performing experiments related to the fungi antagonistic under laboratory conditions (Czapek-Dox 3.34% and malt 1.5% as culture filtrates). Results showed that in Czapek-Dox culture, P. lilacinus (T1) fungi deactivated 52.01% of P. loosi juveniles after 72 hours and this strain didn’t show significant effect on adult mortality. In malt culture, P. lilacinus (T1) fungi deactivated juveniles and adult 32.41% and 30.54%, respectively. In greenhouse condition, antagonistic experiments were carried out in three modes of fungi and nematode inoculation simultaneously, fungi inoculation and two weeks later nematode inoculation and nematode inoculation and two weeks later fungi inoculation. The results showed that if C. rosea inoculated two weeks before nematode inoculation, it could be considerable effect on some indices such as total seedling weight, root fresh weight, root volume and nematode populations in root and soil in comparison with other strains