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

Document Type : Original Article


Department of Plant Protection, Faculty of Agriculture, Zagazig University, Egypt


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 and insignificantly (P≤ 0.05) improved plant growth parameters to certain extent. General means of percentage reduction in galls and egg masses were 58.46 and 54.74%, consecutively.