Characterization and Biocontrol Potential of Predatory Nematodes (Mononchida and Dorylaimida) Against Meloidogyne enterolobii in Thailand

Predatory nematodes are free-living organisms with significant potential to functional as biological control agents against plant-parasitic nematodes.This study investigated the diversity, molecular characterization, and biocontrol potential of predatory nematode from natural soil ecosystems in Thailand.Comprehensive soil sampling from riverbanks and pond ecosystems yielded three predatory nematode genera from the orders Mononchida and Dorylaimida: Mylonchulus sp.(43% occurrence), Mononchus sp.(39.5%), and Paractinolaimus sp.(17.5%).Molecular identification based on 18S and 28S rRNA gene sequences, coupled with morphological examination using De Man Formulae, confirmed the species as Mylonchulus hawaiiensis, Mononchus tunbridgensis, and Paractinolaimus sp.The most abundant species, Mylonchulus hawaiiensis, was selected for targeted bioassays to assess its predation efficacy against Meloidogyne enterolobii, a major root-knot nematode affecting chili crops in Thailand.Experimental results revealed that Mylonchulus hawaiiensis is an active predator of Meloidogyne enterolobii second-stage juveniles (J2s), with an average daily consumption of 16.1 J2s and a cumulative total consumption of 80 J2s over five days.This study provides the first comprehensive documented evidence of Mylonchulus hawaiiensis as a potential biocontrol agent against Meloidogyne enterolobii in Thailand.Although confined to laboratory conditions, these findings establish a critical foundation for future field-based research.The study underscores the potential use of predatory nematodes in developing sustainable, environmentally friendly pest management strategies for agricultural systems.