Opportunistic Fungi, Plant, and Nematode Interactions in Vegetable Crops

Nematodes that parasitize plants are an essential part of the soil ecosystem and have severely damaged vegetable crops all over the globe. In India and other areas of the world, numerous nematodes are associated to various vegetable crops. These include cyst nematodes (Heterodera spp.), root-knot nematodes (Meloidogyne spp.), reniform nematodes (Rotylenchulus sp.), stem and bulb nematode (Ditylenchus spp.), lesion nematodes (Pratylenchus sp.), lance nematodes (Hoplolaimus spp.), etc. Infecting plants by creating galls on the root system, root-knot nematodes are one of the most significant pathogens of vegetable crops. They can also cause plants to exhibit a variety of above-ground signs like stunting, yellowing, and wilting. These nematodes make vegetable products less resistant to different fungi pathogens. Nematodes alter plant roots’ physical and physiological characteristics by fostering a favourable habitat for fungi that cause disease. Additionally, a number of nematophagous or antagonistic fungi, including Paecilomyces spp., Trichoderma spp., Pochonia chlamydosporium, and Verticillium spp., are linked to phyto-parasitic nematodes and control their populations through antagonistic activity. Thus, this chapter aims at focusing the function of fungi in both beneficial and harmful interactions with nematodes on various vegetable crops.