Nematophagal ability of Jordanian isolates of Paecilomyces variotii on the root-knot nematode Meloidogyne javanica

Abstract

The distribution and nematophagal ability of local isolates of Paecilomyces variotii against the root-knot nematode (RKN), Meloidogyne javanica, was investigated under laboratory conditions. Eighty RKN-infected root samples from fig trees, tomato, aubergine and cucumber were collected from three geographical areas of Jordan (Safi, Central Jordan Valley and Jerash). Paecilomyces variotii occurred in 10% of the samples and was found in both females and egg masses of M. javanica. The local isolates of P. variotii, as nematode antagonists, resulted in egg parasitism of about 61.4% compared to 68.5% for P. lilacinus. Moreover, both species were able to parasitize females and freed eggs and to reduce hatch of second stage juveniles. Under laboratory conditions, P. lilacinus parasitized females on agar plates significantly more than local isolates of P. variotii. Isolates of Paecilomyces lilacinus and P. variotii parasitized heat-killed eggs to similar extents, but at rates higher than those of live eggs inside egg masses, suggesting that both species possess high saprophytic ability.