Effect of nematophagous fungi on reproduction of Meloidogyne enterolobii on guava (Psidium guajava) plants
Abstract The root-knot nematode, Meloidogyne enterolobii, is a major disease of guava, Psidium guajava, in Brazil and other countries. Egg-pathogenic fungi are considered potential biological control agents of root-knot nematodes and are associated with suppression of Meloidogyne spp. Glasshouse experiments were conducted in order to evaluate the effect of the fungi Paecilomyces lilacinus and Pochonia chlamydosporia on a population of M. enterolobii growing on guava plants. Guava seedlings of about 15-20 cm growing in plastic bags were inoculated with 10 000 eggs of M. enterolobii plant−1. Two months later, three isolates of P. lilacinus and one isolate of P. chlamydosporia were inoculated in the infested plants. The effect of the treatments was evaluated 6 months later. Although plant infection by nematodes was not attenuated, the number of eggs (g roots)−1 fell significantly. The number of egg masses infected with the fungi was inversely correlated with the number of eggs found in the roots. The most effective result (61.5% of control) was obtained with the isolate CG1003 of P. chlamydoporia, which was originally isolated from eggs of M. enterolobii in Brazil, followed by P. lilacinus (CG959 and CG1038) with about 40% of control. These fungi showed the ability to colonise healthy guava roots in glasshouse experiments. These results suggest that P. chlamydosporia can be selected as a potential biological control agent to be employed with other strategies in integrated management to control M. enterolobii on guava.