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loss in infected plants could be due to metabolic leakage of carbohydrate throughout the post-

infection phase, particularly in the early gall stage (Rashid et al., 1985). The stored
carbohydrate, which is transformed into utilisable form by the action of hydrolytic enzymes

released by the nematodes, is one of the most important sources of energy gained from the
host (Singh et al., 1978). The host plant infected by Meloidogyne spp. showed a reduction in

starch (Vaithesswaran et al., 2006; Sharma et al., 1996). Various studies have shown a
decrease in chlorophyll pigments and total chlorophyll concentration in root-knot nematode-

infected plants (Mohanty et al., 1997; Abbasi et al., 2008).

MATERIAL AND METHODS
Preparation of sand soil mixture

For plant rearing in the laboratory, River soil, Garden soil, and Red soil were mixed in

a 3:1:1 ratio. To remove the coarse particles, the mixture has meshed. To kill numerous
bacterial and pathogenic organisms contained in the sand and soil mixture, it was sterilized in

an autoclave at 15 lbs, pressure for 2 hours (Fred and Wakesman, 1928).
Seedling Culture

Before sowing, the seeds of Abelmoschus esculents were surface sterilized with a 0.1
% mercuric chloride solution and washed six times for five minutes in sterile water. In

sterilized pots holding 1.5 kg sterilized sand-soil mixture, five seeds were sowed. Seedlings

were reduced to one plant per pot seven days after germination to ensure uniform
development and vigour. The seedling was allowed to grow up to2 leaves and a bud stage.

After this, they were ready for inoculation.
Source of Inoculums

As primary inoculums, mature egg masses of M. incognita were isolated from the
plant Acalypha indica L. The egg masses were surface sterilized with a 0.01% sodium

hypochlorite solution before being placed to brass gauze filters with mull cloth overlay. For

hatching, the gauze assembly was placed in a small plastic vial (1"x1") and kept in touch with
a small amount of water at the bottom. Freshly hatched juveniles were collected and used for

inoculation.

Inoculums of Pathogen

2000 second-stage larvae were pipette evenly into four holes dug among the seedlings
in the soil of the pots to promote infection from all sides around the roots. After that, the

holes were covered with a thin layer of sterilized sand and lightly watered. All the plants such

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