Biological Control of the Citrus Nematode (¬Tylenchulus semipenetrans¬) by Antagonistic Fungi in Greenhouse Condition

In order to biological control of the the citrus nematode، Tylenchulus semipenetrans، soil and root samples were collected from citrus orchards in east of Guilan and west of Mazandaran. The juveniles were extracted from soil while eggs and females from roots. To isolate the antagonistic fungi، suspension of eggs and juveniles were cultured separately on water agar media containing streptomycin. The identified fungi were Paecilomyces lilacinus، Fusarium oxysporum، Acremonium strictum، Fusarium solani and cladosporium cladosporioides. To determine fungal antagonistic activities on citrus nematode، fungal treatments were evaluated in greenhouse conditions. Fungal nematicidal properties were compared with Fenamiphos (Nemacur) as a systemic nematicide belonging to organophosphate group. Two indices including the number of female per gram root and population of juveniles in 100gr soil were recorded. Results indicated that all fungi isolates had suppressive effect on T. semipenetrans. Compared Means revealed that P. lilacinus and A. strictum had the most effects on reduction of nematode population. C. cladosporioides showed the minimum effect on nematode control. Evaluation the time of inoculation showed that inoculating nematode 20 days after adding fungi had better results than other treatment. Among fungal species P. lilacinus and A. strictum were more effective than other species. However، Fusarium solani and F. oxysporum showed good effectiveness.