Protecting Groundnut Crops from Kala Tora & Root-Knot Nematodes: Boosting Pod Fill, Shelling Percentage & Kernel Tonnage

Groundnut is a major oilseed crop where pegs enter the soil to form subterranean pods, exposing both roots and fruit directly to soilborne pests. Root-knot nematodes cause swellings and galls on primary roots and pegs, while lesion nematodes feed on pod walls, creating dark brown or black lesions ("Kala Tora" disease). Above ground, groundnut fields exhibit patchy stunting, leaf chlorosis, and premature leaf drop. Underground, affected plants produce fewer pods, small kernels, low oil content, and a high percentage of unfilled shells ("pops").

Nematode lesions on pod walls also allow Aspergillus flavus fungi to enter, increasing dangerous aflatoxin contamination risks. Effective control requires bio-seed dressing before sowing, applying bio-nematicides like Purpureocillium lilacinum and Trichoderma into furrow soil during planting, incorporating neem cake during field preparation, and rotating with non-host cereal crops like pearl millet or sorghum.

Biological nematode management offers a sustainable alternative to repeated chemical nematicide applications while improving long-term soil health. Beneficial microorganisms including Paecilomyces lilacinus, Pochonia chlamydosporia, Trichoderma harzianum, Trichoderma asperellum, Bacillus subtilis, Bacillus amyloliquefaciens, Pseudomonas fluorescens, and Streptomyces species naturally suppress nematode populations while improving root health and soil fertility.

Paecilomyces lilacinus parasitizes nematode eggs and reproductive females, reducing egg production and interrupting the nematode life cycle. Pochonia chlamydosporia attacks nematode egg masses in the soil, preventing juvenile nematodes from hatching and gradually reducing nematode populations over successive crop seasons.

Trichoderma species rapidly colonize the groundnut rhizosphere, stimulating feeder root growth while suppressing important soil-borne fungal pathogens. Stronger root systems improve nutrient uptake and promote better nitrogen fixation, resulting in vigorous vegetative growth, increased peg formation, and improved pod filling.

Beneficial bacteria such as Bacillus subtilis and Pseudomonas fluorescens improve nutrient solubilization, produce natural antimicrobial compounds, and stimulate systemic resistance within groundnut plants. Streptomyces species further enrich the rhizosphere by producing bioactive metabolites that suppress harmful microorganisms while maintaining a healthy microbial ecosystem.