Isolating a group of fungi from soil with the ability to control root-knot nematodes (Meloidogyne spp.) damage in vegetables

Vegetable cultivation is essential to Vietnam’s agricultural development strategy. Meloidogyne spp. has caused a root-knot disease which is dangerous due to decreased plant vitality, yield, and quality. This research aimed to select fungal strains controlling Meloidogynes spp., which causes root knots in vegetable plants. As a result, strains of the fungi Paecilomyces sp., Mariannaea sp., and Penicillium sp. effectively inactivated second-stage juveniles (J2) after 72 h of inoculum. Specifically, Paecilomyces sp. was immobilized in 64.5% of the nematodes, Mariannaea sp. was 72%, and Penicillium sp. was 70%, compared to only 13.5% in the control group without fungal inoculation. In a net house experiment investigating the influence of fungal strains on J2 in Malabar spinach (Basella alba L.), the Mariannae sp. strain inoculated on plants at a density of 107 cfu/mL produced the best results in terms of root length (25.3 cm) and root weight (0.4 g) compared to the control uninoculation (18.5 cm; 0.3 g) and the control with only the nematode (11.2 cm; 0.2 g). Additionally, the Mariannaea sp. strain significantly reduced the number of juvenile nematodes per 50 g of soil (15.7 J2) compared to the control (160 J2) in Malabar spinach (Basella alba L.) in a net house.