Pumpkins (Cucurbita moschata), valued for their nutritional, medicinal, and economic significance, face threats from Meloidogyne incognita, a critical plant-parasitic nematode. This study extensively examines the impact of M. incognita on the growth, physiological, and biochemical responses of C. moschata. We demonstrate that M. incognita infection leads to significant growth impairment in C. moschata, evidenced by reduced plant height and biomass, along with the significant development of nematode-induced galls. Concurrently, a pronounced oxidative stress response was observed, characterized by elevated levels of hydrogen peroxide and a significant increase in antioxidant defense mechanisms, including the upregulation of key antioxidative enzymes (superoxide dismutase, glutathione reductase, catalase, and peroxidase) and the accumulation of glutathione. These responses highlight a dynamic interaction between the plant and the nematode, wherein C. moschata activates a robust antioxidant defense to mitigate the oxidative stress induced by nematode infection. Despite these defenses, the persistence of growth impairment underscores the challenge posed by M. incognita to the agricultural production of C. moschata. Our findings contribute to the understanding of plant–nematode interactions, paving the way for the development of strategies aimed at enhancing resistance in Cucurbitaceae crops against nematode pests, thus supporting sustainable agricultural practices.

Bursaphelenchus rainulfi is a pine-associated, non-pathogenic nematode that serves as a motile comparative species for evaluating nematophagous fungi. We investigated the in vitro biocontrol activity of Purpureocillium takamizusanense strain PMEPF27, originally isolated from insect cadavers in Taiwan, against mixed motile stages of B. rainulfi. Identity of the fungus was confirmed by morphology and ITS/EF-1α sequencing. Nematodes were exposed in liquid suspension to PMEPF27 conidia, with sterile water as the negative control and fluopyram as the positive control. Mortality was monitored over 7 days, and scanning electron microscopy was used to observe fungus–nematode interactions. PMEPF27 caused significantly higher mortality than the water control, reaching ~80% by day 7, and showed surface disruption of nematode cuticles, although no direct spore penetration was observed. These findings expand the nematophagous profile of P. takamizusanense beyond egg and sedentary stages, validate B. rainulfi as a motile comparative species in pine-nematode bioassays, and highlight PMEPF27 as a promising candidate for biocontrol development.

Plant-parasitic nematodes, particularly the root-knot nematode Meloidogyne incognita, severely threaten agricultural production in tropical and subtropical regions. Although nematode-trapping fungi have been considered environmentally friendly alternatives to chemical nematicides, their field performance often remains inconsistent due to limited ecological adaptation. This study combined a field survey of crop-associated nematode communities with laboratory and greenhouse evaluation of selected nematode-trapping fungal isolates under subtropical conditions. Field surveys across multiple crops identified M. incognita as the dominant plant-parasitic nematode species. Five fungal isolates with different trapping mechanisms were compared for growth under contrasting nutrient conditions and nematode-trapping efficiency. Among them, Drechslerella brochopaga (NTF2), which forms constricting rings, showed superior growth stability under nutrient-limited conditions and the highest nematode mortality in vitro. In greenhouse experiments, NTF2 reduced root gall formation in two of three independent trials, indicating potential but variable suppression of M. incognita on pumpkin. These findings highlight the importance of ecological adaptation and trapping strategy in determining the effectiveness of nematode-trapping fungi for sustainable nematode management.