Abstract:
Tomato is one of the most widely cultivated vegetable in the tropical and subtropical
regions of the world. Root-knot nematode (RKN) species, Meloidogyne incognita and
M. javanica are serious constraints to vegetable crops, especially tomato under
protected cultivation, causing yield loss up to 25-100%. In the present study
rhizobacterial isolates from polyhouse tomato cultivars were isolated and
assessed for M. incognita antagonism. Among 80 isolates that were tested for
mortality of M. incognita juveniles (J2s). The results show that cell free filtrate (CFF)
of four rhizobacterial isolates (B. pumilus, B. megaterium, B. cereus and B subtilis)
caused high mortality (>90%) in M. incognita J2s on exposure at 24h. Egg masses kept
in CFF showed significant (p< 0.05) hatch inhibition in the range of 85.04 to 100%
compared to control, on incubation for 21 days. Among the treatments, B. subtilis
caused maximum inhibition (88.6-100 %) followed by B. pumilus (83-100%), B. cereus
(81.5-94.7%), and B. megaterium (78.83-90.7%) as compared to control. Pluronic gel
bioassays using tomato seedlings (cv Pusa Ruby) revealed that significantly reduced (p
<0.05) juvenile (J2s) attraction towards the rhizobacteria treated roots on observation
at 2h and 4h.The maximum inhibition was observed with B. subtilis treatment where
an average numbers of J2s that reached a distance of 0.5-1.0 cm were 15-20 at 2h in
treated plates as compared 29 -30 in control treatment.. The rhizobacterial isolates
were significantly (p <0.05) reduced nematode infection Thus the rhizobacterial
isolates were antagonistic to M. incognita in tomato. Their utilization in
polyhouses is a promising approach for management of M. incognita in tomato.
