Suppression of the Root-Knot Nematode,Meloidogyne incognita in Tomato Plants by Application of Certain Entomopathogenic Nematode Species Under Greenhouse Conditions

Abstract

The suppressive effects of six species of entomopathogenic nematodes (EPNs) against Meloidogyne incognita infected tomato were assessed in two separate trials under greenhouse conditions. The tested EPN species were Heterorhabditis bacteriophora, H. megidis, H. zealandica, Steinernema feltiae, S. glaseri and S. riobravae. In the first trial, EPNs were applied as a liquid suspension of alive or dead infective juveniles (IJs) at rate of 5000 IJs/plant in sandy and clay soils, while in the second trial, two Galleria mellonella infected cadavers of six-day old per plant were used in sandy soil. In the two experiments, application of EPNs was accomplished simultaneously with inoculation of M. incognita. Carbofuran as a standard synthetic nematicide was used as comparison treatment at recommended rate of 0.2 g/plant. Control treatments received only water and M. incognita at rate of1000 IJs/plant. Two months after inoculation, galling (as indicated by number of galls/plant) and reproduction (as indicated by number of egg masses /plant) as well as damage (as indicated by fresh and dry weight of areal parts) were assessed. Data showed that, treatment of carbofuran surpassed all other treatments in minifying galling and reproduction of M. incognita in sandy and clay soils. On the other hand, curative applications of alive or heat-killed IJs significantly (P≤ 0.05) diminished gall formation and egg mass production in tomato roots with slightly amelioration in fresh and dry weight of tomato shoot. Steinernematid species were more comparatively effective than heterorhabditid ones. General means for number of galls and egg masses for steinernematid species were 52.50 and 25.33 with percent reduction of 55.45 and 64.49 %, respectively. Whereas, the parallel values for heterorhabditid species were 69.67 and 36.33 with percent reduction of 40.88 and 49.07%, respectively compared to treatment of M. incognita alone. Treatments of alive IJs overwhelmed those of dead IJs in decreasing number of galls (with percent reduction of 56.53 and 39.79% respectively) and egg masses (with percent reduction of 63.16 and 50.39%, successively). Moreover, utilization of two G. mellonella infected cadavers markedly lowered number of galls and egg masses

Effect of Different Bioagents on the Population Density of Meloidogyne incognita Infected Tomato Plants

“…These findings suggest the possibility of exploiting the antagonistic potential of EPNs for biological control of PPNs. Moreover, it has been shown that EPNs can affect the populations of RNKs infecting plants, when they are applied near the root system (El-Ashry et al, 2018).…”

“…Steinernema feltiae was obtained kindly from a pure culture by Dr. Ahmed Azaze from Entomology and Nematology, Agricultural Research Center, Giza, Egypt. It was separately cultured in last instar larvae of the greater wax moth Galleria mellonella L. this technique according to El-Ashry et al (2018). At the same time of adding M. incognita infection, the predatory nematode, D. lheritieri was added at a rate of 100 individual per pot, as well as entomopathogenic nematode, Steinernema feltiae was Egypt.…”

“…Agronematol., Vol. 21, No.1 (2022) added at the same time of adding root knot nematode at the rate of 5000 IJs per pot, for single or combined treatments (El-Ashry et al, 2018).…”

“…Agronematol., Vol. 21, No.1 (2022) reduced root knot nematode, M. incognita juvenile infected tomatoes (El-Ashry et al, 2018). Diplogaster lheritieri has proved to be successful in biological control programs for plant parasitic nematode.…”

Impact of Plant Oils, Biocontrol Agents and Oxamyl on Galling and Reproduction of Meloidogyne incognita Infecting Pepper Cultivars

“…Also, Steinernematidae (S.feltiae and S. riobravae) but not Heterorhabditidae (H.indica) were found intercellular in the root cortex of soybean plants that had been infected with RKN (Fallon et al, 2002). Moreover, El-Ashry et al (2018) showed that EPNs belonging to steinernematids were more effective than those belonging to heterorhabditids in controlling M. incognita infecting tomato.…”