Potential of Trichoderma harzianum and Paecilomyces lilacinus as Biocontrol Agents for Meloidogyne javanica on Tomato

Abstract

The effects of Trichoderma harzianum and Paecilomyces lilacinus on egg hatching and the mortality of Meloidogyne javanica second-stage juveniles (J2) were evaluated, in vitro, under laboratory conditions. Both the tested fungi have significantly (P ≤ 0.05) suppressed the egg hatching of M. javanica by 22.0-37.2%, compared to the control. However, the effects of T. harzianum and P. lilacinus on the mortality of M. javanica J2s were much greater. J2s mortality (%) increased by the time from 4 to 7 to 10 days after exposure, and finally both fungi caused 80.57-83.12% mortality of M. javanica J2s, after 10 days of exposure. The effects of T. harzianum and P. lilacinus on the growth of tomato plants “cv. Newton“ infected with M. javanica and the nematode reproduction were evaluated under greenhouse conditions. Results showed that the inoculation of tomato plants with 10,000 eggs of M. javanica/plant caused a significant reduction (P ≤ 0.05) of their plant growth parameters, compared to the non-treated checks. However, the treatments with T. harzianum and P. lilacinus significantly increased (P ≤ 0.05) the plant fresh weight and height of the infected tomato plants, compared to those of the plants infected only with M. javanica. Besides, the fungal treatments also reduced (P ≤ 0.05) the number of galls/plant, and the nematode reproduction expressed in the number of egg masses, number of eggs/plant and the nematode reproduction factor (Rf). The effects of the introduction time of T. harzianum and P. lilacinus into the soil on their biocontrol potential against M. javanica on tomato plants were evaluated under greenhouse conditions in two separate experiments. The tested fungi were added simultaneously and 5, 10 and 15 days, either before or after the infestation of the soil with 2 M. javanica eggs, in addition to the control treatments. Results showed that all of the tested T. harzianum and P. lilacinus applications suppressed (P ≤ 0.05) M. javanica reproduction and the root damage of the tested tomato plants while, increased (P ≤ 0.05) the tomato growth. The early applications with T. harzianum and P. lilacinus (5, 10 and 15 days before M. javanica) superimposed the simultaneous and other applications with the fungus and the nematode in general. The treatment with T. harzianum and P. lilacinus, 15 days before nematode infestation gave the best results in suppressing the nematode reproduction and increasing the growth of nematode-infected plants in this study.