Biological control of citrus nematode (Tylenchulus semipenetrans) using antagonistic fungi

In order to identify antagonistic fungi of citrus nematode (Tylenchulussemipenetrans) in the east of Guilan and west of Mazandaran, soil and root samples were collected from infested orchards. Juveniles, eggs and females were extracted from soil and roots. To isolate the antagonistic fungi, suspensions of eggs and juveniles were cultured separately onwater agar media containing streptomycin. Hyphale growing from nematodes and eggs or female fragments were purified on W. A. and were transfered to PDA plates for identification. The fungi identified were Paecilomyces lilacinus, Fusarium oxysporum, Acremonium strictum, Fusarium solani and Cladosporium cladosporioides. These fungi were evaluated in vitro for their parasitism of eggs and their effects on egg hatch and juvenile mortality. Results showed that all isolates of fungi parasitized Tylenchulus semipenetrans eggs, inhibited egg hatch and killed juveniles. Among them, Paecilomyces lilacinus and Acremonium strictum were the most efficient and parasitized 79.11 and 70.66 % of eggs 5 days after inoculation, respectively. The highest percentage of second-stage juvenile (J2) morality (48.33 %) was observed in samples treated with Acremonium strictum.