BIOLOGICAL CONTROL OF PHYTOPARASITIC NEMATODES BASED ON MICROORGANISMS (REVIEW)

Abstract

Phytoparasitic nematodes are dangerous pests of agricultural crops. Annually, yield losses due to damage by phytonematodes are up to 15%, which is estimated at billions of dollars. The aim of the research is to summarize and analyze scientific publications concerning the harmfulness of phytoparasitic nematodes and microorganisms that have an antagonistic effect against them for the further development of biopreparations of nematicidal action based on antagonist bacteria. The study objectives are to identify the most common groups of nematodes, review the information concerning microorganisms that have a nematicidal effect and biological products based on them. The review considers the main representatives of nematodes – plant parasites and notes their habitat, harmfulness, affected crops and symptoms of infection. Brief descriptions of life cycles and systematic affiliation are given. Analysis of scientific publications on the studied topic shows that numerous microorganisms are capable of exhibiting nematicidal activity, directly or indirectly affecting nematodes in the soil. In the course of the analysis of literary sources, it was found that both fungi and bacteria can exhibit an antagonistic effect against phytoparasitic nematodes. It is noted that for both groups of microorganisms, there are several mechanisms of action: predation, parasitism, competition, etc. It has been found that fungi and bacteria synthesize metabolites of various natures with a nematicidal effect: toxins, lytic enzymes, antibiotics, siderophores. It should be noted that microorganisms-antagonist are capable of exhibiting nematicidal activity to nematodes of different stages of the life cycle: eggs, juveniles and adults. Nowadays, some commercial preparations based on antagonist microorganisms are successfully used in agriculture in different countries. During the analysis, it was discovered that to date, few viruses are capable of infecting nematodes; their systematic affiliation has also been established. It is noted that, if compared to bionematicides based on fungi and bacteria, not a single bionematicide based on viruses has been developed. The development of bionematicides based on antagonist microorganisms is a promising area but requires further studies of interactions in the plant-nematode-microorganism system.