Root-knot nematodes (Meloidogyne spp.) are obligate endoparasites among the most destructive agricultural worldwide causing substantial yield losses across numerous crops. Current management options are limited, and the overuse of chemical nematicides poses serious risks to human health and the environmental. In this study, a bacterial isolate obtained was investigated as a biocontrol agent against Meloidogyne incognita, identified as Pantoea conspicua strain PC (GeneBank accession no.ON203125) based on 16S rRNA gene sequencing. Exposure of second-stage juveniles (J2s) caused mortality rates of 67.9%, 94.7%, 97.7%, and 99.3% in M. incognita at 12, 24, 48, and 96 hours after exposure to a 100% concentration of bacterial filtrate, respectively. In comparison, bacterial pellets resulted in 18.5%, 51.8%, 62.9%, and 82.9% mortality at the same time intervals. Both, the bacterial filtrate and pellets significantly inhibited egg hatchability in vitro. Greenhouse experiment demonstrated that tomato plant treated with the bacterial filtrate or pellets exhibited marked improvements in root and shoot growth parameters. Specifically, the bacterial filtrate caused reduced the number of galls, eggs, and eggmasses per gram of root by 93.12%, 97.9%, and 79.9% respectively, along with a 92.7% decrease in J2s per 250 grams of soil. Overall, P. conspicua strain PC demonstrated high potential as a biocontrol agent, offering advantages in its mode of action, efficacy, and contribution to ongoing nematode management, while also reducing environmental impact and supporting integrated pest management strategies.
Ghareeb et al. (Fri,) studied this question.