Abstract
Biological control using rhizosphere bacteria,
Pseudomonas
spp. and
Serratia
spp. is a prospective alternative technique to overcome plant parasitic nematodes infection. So, the current study was conducted
in vitro
on five egg-masses, 100 free eggs and 100 infective juveniles (IJs) of
Meloidogyne incognita
as well as greenhouse treatments on
Luffa aegyptiaca
L. to evaluate the nematicidal potential of six strains belong to
Pseudomonas
spp. and
Serratia
spp. as compared to oxamyl.
Results showed that the inhibitory effect and juvenile mortality varied according to bacteria species, strains and exposure time. All the tested bacteria significantly (
P
≤ 0.05) inhibited egg hatching and increased juvenile mortality
in vitro
. After 3 days of treatment,
Pseudomonas
spp. were more effective against eggs (48.31to 55.15%) and IJs (20.98 to 25.30%) than
Serratia
spp. (44.55 to 49.75% with eggs) and (19.06 to 21.61% with IJs), respectively. In the pot experiment,
Luffa aegyptiaca
L. treated with
Serratia
spp. and
Pseudomonas
spp. displayed significantly higher (
P
≤ 0.05) levels of growth (as indicated by root length, fresh roots weight and fresh shoots weight) compared to control plants and significantly (
P
≤ 0.05) suppressed galling (number of galls) and reproduction (as indicated by number of egg-masses on roots and number of eggs and juveniles in pot soil). Meanwhile, among the treated plants,
Serratia
spp. and
Pseudomonas
spp. gave the best results in shoot weight of pots infected by eggs of
M. incognita
than those infected with IJs as compared with positive control. While, oxamyl treatment gave the best results in pots infected by eggs and IJs.
The lowest galling (gall index), number of eggs and juveniles in soil was observed in the treatment with mixture of
Serratia
spp. and
Pseudomonas
spp. as well as, enhanced growth of sponge gourd more than application each of them alone. Pots treated with oxamyl overwhelmed those treated with mixture of
Serratia
spp. and
Pseudomonas
spp.