Chilli Root-Knot Nematode Control Using Biological Microorganisms

Chilli (Capsicum annuum L.) is one of the most important spice and vegetable crops cultivated across India and many other countries. It is grown for fresh consumption, dried chilli production, and processing into powders, sauces, and oleoresins. However, chilli is highly susceptible to plant-parasitic nematodes, especially Root-knot nematodes (Meloidogyne spp.), which are among the most destructive soil-borne pests affecting crop productivity. Severe infestations can reduce chilli yields by 25–70%, while also increasing the incidence of fungal and bacterial diseases.

Root-knot nematodes invade young roots and establish feeding sites, resulting in characteristic root galls. These galls interfere with the movement of water and nutrients, causing nutrient deficiencies, poor plant growth, and reduced flowering. Damaged roots also become ideal entry points for soil-borne pathogens such as Fusarium oxysporum, Rhizoctonia solani, Pythium spp., and Phytophthora capsici. As a result, nematode-infested chilli plants often suffer from disease complexes that are more damaging than nematode infection alone.

The most common nematodes affecting chilli include Root-knot nematodes (Meloidogyne incognita, Meloidogyne javanica), Lesion nematodes (Pratylenchus spp.), and Reniform nematodes (Rotylenchulus reniformis).

Biological nematode management offers a sustainable solution that reduces nematode populations while improving soil fertility and root health. Beneficial microorganisms establish around the root zone, suppress harmful organisms, and promote stronger plant growth throughout the crop cycle.

Paecilomyces lilacinus parasitizes nematode eggs and females, reducing egg hatching and gradually lowering nematode populations. It provides excellent long-term suppression when applied regularly to the root zone.

Pochonia chlamydosporia colonizes the rhizosphere and attacks nematode eggs, providing continuous biological suppression while enhancing beneficial soil microbial activity.

Trichoderma spp. improve root development, protect roots from fungal infections, increase nutrient availability, and stimulate natural plant defense mechanisms. They are especially valuable in chilli fields where root diseases frequently occur alongside nematode infestations.

Pseudomonas spp. rapidly colonize chilli roots and produce antimicrobial compounds, siderophores, enzymes, and plant growth-promoting substances. They also activate induced systemic resistance (ISR), helping plants better tolerate nematode and disease pressure.

Bacillus spp. produce beneficial enzymes, antibiotics, and phytohormones that promote healthy root development while suppressing several soil-borne pathogens and contributing to biological nematode management.

Combining these microorganisms into a biological consortium provides multiple mechanisms of action against nematodes while improving soil structure, nutrient cycling, flowering, fruit setting, and overall crop performance. This approach is suitable for open-field cultivation, drip irrigation systems, protected cultivation, and organic farming.

Common Chilli Nematodes

• Root-knot nematode (Meloidogyne incognita)
• Root-knot nematode (Meloidogyne javanica)
• Lesion nematode (Pratylenchus spp.)
• Reniform nematode (Rotylenchulus reniformis)

Biological Benefits

• Reduces nematode egg hatching
• Suppresses juvenile nematodes
• Promotes healthy root growth
• Improves nutrient uptake
• Reduces root gall formation
• Enhances flowering and fruit set
• Improves soil microbial diversity
• Reduces dependence on chemical nematicides
• Supports sustainable chilli cultivation