Nematocidal activity of fungal filtrates on eggs and juveniles of five species of sedentary endoparasitic nematodes.

Research efforts are needed to develop new biocontrol strategies against plant-parasitic nematodes (PPNs) to replace chemicals and maintain sustainable crop production. In this study, filtrates obtained from fungi isolated from cyst nematodes (Heteroderidae) were evaluated for activity against eggs and second-stage juveniles (J2) of five PPNs: , , and . Initially, filtrates of 42 fungal isolates were evaluated for effects on and egg viability. After the initial screening, six of the fungal isolates were selected for further evaluation against additional PPN eggs and J2 based upon evidence of usage in other studies, fast growth, and frequency of isolation. Filtrates from JB217, JB201, JB209, and JB98 reduced egg viability by >80%. sp. JB70, JB173, and JB209 reduced egg viability by >50% but had negligible effect on the J2 stage of this nematode. Filtrate from JB201was the most lethal against PPNs, immobilizing ~100% of J2 of all nematode species while filtrate from JB217 only immobilized J2 of , and . These fungal filtrates are therefore promising alternative sources of natural bioactive substances for the potential management of PPNs.