Field evaluation of Trichoderma harzianum grown on different media for the management of potato root-knot nematode and enhancement of enzymatic antioxidant activities

Abstract Meloidogyne root-knot nematodes represent a major global challenge in potato agriculture. A field investigation was carried out to evaluate the impact of soil infestation with Trichoderma harzianum on potato infection by Meloidogyne incognita and its population dynamics. Various media, including rice straw, rice extract, pumpkin bran, pumpkin starch, and milk extract, were used for cultivating the fungal inocula. The treatments significantly reduced second-generation populations in soil as well as the numbers of females, galls, and egg masses in roots, while enhancing potato growth and yield. The combined treatment of T. harzianum + milk extract + furfural, achieved the greatest reductions, reaching 87.7% and 71.85% in J2 per 250 g of soil at mid and harvest times, respectively, and 91.8% and 61.95% in J2 per 5 g of roots compared with the untreated control. The treatments resulted in notable improvements in potato plant growth, yield components, tuber number and weight per plant, and overall yield per treatment. Additionally, application of T. harzianum grown on different media significantly increased the activities of peroxidase (POD), polyphenol oxidase (PPO), and superoxide dismutase (SOD), and induced distinct isoenzyme patterns compared with the control. These treatments represent effective alternatives to chemical fungicides for managing potato root diseases.