EVALUATING SOIL FUNGAL ISOLATES FOR CONTROLLING ROOT-KNOT NEMATODE INFESTATION ON TOMATO PLANTS

Abstract:

The root-knot nematode (Meloidogyne incognita) poses a significant threat to tomato plants, causing substantial economic losses. The use of chemical nematicides has proven both ineffective and environmentally harmful, prompting the exploration of alternative control measures. This study focused on evaluating the nematicidal potential of soil-derived fungal isolates against second-stage juvenile Meloidogyne incognita.

Soil samples were collected from botanical gardens and infested tomato farms to isolate fungi and nematodes. Fungi were isolated using a serial dilution method, while nematodes were extracted using the pie-pan technique. In vitro assessments of fungal antagonism against M. incognita were conducted using potato dextrose broth. Subsequent in vivo experiments took place in a screen house, where healthy, sterilized tomato seeds were planted in 7-liter plastic buckets containing 5 kg of sterilized loamy soil. The buckets were arranged in a randomized block design, with three replicates. After two weeks of seed germination, each bucket was thinned to one plant. One thousand second-stage juvenile M. incognita were introduced into four holes around the stem of each plant, followed by the inoculation of 10 ml of fungal culture filtrate into the same holes on the following day.

Four distinct fungal species were isolated: Aspergillus niger, Aspergillus nidulans, Penicillium chrysogenum, and Rhizopus stolonifer. The nematode identified was M. incognita. The fungicidal activity against M. incognita was evaluated after 24 and 48 hours, yielding percentages of control for A. niger (39.28% and 78.47%), A. nidulans (29.12% and 57.49%), P. chrysogenum (18.59% and 47.48%), and R. stolonifer (8.05% and 26.43%).

In the in vivo experiment, A. niger exhibited the most favorable outcomes in terms of average plant height at maturity, fruit yield per plant, and number of leaves per plant (46.43 cm, 10.33, and 69.67, respectively). Conversely, R. stolonifer displayed the lowest results for these parameters (26.13 cm, 5.33, and 46.33, respectively), while demonstrating the highest number of galls per plant root (16.67). Statistical analysis indicated significant differences (P<0.05) between A. niger and R. stolonifer. Disease incidence was notably higher in the control group at harvest (39.49%), contrasting with A. niger, which exhibited the lowest incidence (7.18%) after treatment. The divergence between control and A. niger was statistically significant (P<0.05).

This study suggests that the identified fungal species hold potential as biological agents for effective root-knot nematode management and could serve as bio-fertilizers to enhance plant growth parameters.

EVALUATING SOIL FUNGAL ISOLATES FOR CONTROLLING ROOT-KNOT NEMATODE INFESTATION ON TOMATO PLANTS.   GET MORE, ACTUARIAL SCIENCE PROJECT TOPICS AND MATERIALS