Organic and inorganic fertilizers, commercial products containing organic and
amino acids, vitamins as well as plant growth regulators were tested for their ability
to induce nematode resistance in eggplant. Results indicated that organic fertilizers
are significantly better than inorganic ones in reducing all the root-knot nematode
counts with superiority to compost, Hyper K® and Union zinc® were the best
inorganic fertilizers, although, they all could not reach the effect of vydate 10% G.
All the tested commercial products containing organic and/or amino acids as well as
plant growth regulators reduced significantly M. incognita counts. Indole acetic acid
and indole butyric acid preceded all the tested materials in enhancing the resistance
of eggplant against the root-knot nematode followed by ascorbic acid, amino zinc
and citric acid. Results also proved that organic fertilizers (especially compost) were
the best in improving plant growth. Other organic and inorganic materials
significantly improved eggplant growth. Indole acetic acid, indole butyric acid,
ascorbic acid, citric acid and amino zinc performed the best results.
Oxidant lipid peroxidase (MDA) was at the lowest values in roots of healthy
plants and at the highest ones in the infected roots of untreated plants. Application
of all the tested materials could preclude the formation of MDA. Only indole acetic
acid, compost and indole butyric acid, in that order, brought the levels of MDA in
infected roots to be near to that of the healthy plants without significant differences.
The antioxidant enzymes SOD and APX increased in infected plants as a feed back
to the increase in MDA. Also indole acetic acid, indole butyric acid and compost
encouraged plants to produce levels of SOD and APX significantly higher than
those of other treatments including healthy plants. The other tested materials
heighten the levels of antioxidant enzymes to levels measured up the degree of
nematode control they accomplished.