Efficacy of fungal and bacterial consortia against root-knot nematodes (Meloidogyne spp.) on tomato

Root-knot nematodes Meloidogyne spp. are a significant factor in reducing tomato productivity, necessitating the search for biological methods to limit their harmfulness. The aim of the study was to evaluate the effectiveness of fungal and bacterial consortia against root-knot nematodes on tomato. The work was carried out in 2026 in Krasnodar. In the first stage, the compatibility of the fungal strains T. harzianum, T. Ghanense, and T. atroviride with the bacterial strains B. thuringiensis, B. mycoides, and P. silesiensis was assessed on a solid nutrient medium PSA. The following strains were found to be compatible: T. harzianum + B. mycoides, T. ghanense + B. mycoides, T. atroviride + B. thuringiensis, T. atroviride + B. Mycoides, and T. atroviride + P. silesiensis. In the second stage, the nematicidal activity of single strains and consortia of microorganisms against the second instar larvae of M. hapla J2 was determined. The highest nematicidal activity in the experiment was demonstrated by the T. ghanense + B. mycoides consortium, with which the mortality of M. hapla J2 after 72 hours reached 88.8%, and 85.6% when using the culture liquid after filtration. In the third stage, the biological effectiveness of single strains and consortia of microorganisms was studied in a pot experiment on the Prima Dona F1 tomato hybrid in vessels (5 l) with steamed soil (deep leached heavy loamy chernozem with a humus content of 4.0%, pH 6.8 units). Infection with a suspension of M. hapla was carried out at a rate of 500 larvae per plant. Microbial consortia reduced gall numbers to 7.4-10.2 galls per plant with a biological effectiveness of 82.4-87.2%. Yields ranged from 2.5-2.6 kg per plant to 1.8 kg in the infected control. Compatible fungal and bacterial consortia were more effective than single strains and may be considered a promising biological control for M. hapla on tomato.