Study on Compatibility between Bio-agents and Fungicides and their in-vivo and in-vitro Efficacy against Fusarium oxysporum f. sp. pisi Causing Wilt of Field Pea

Background: Fusarium wilt, caused by soil borne pathogen F. oxysporum f. sp. pisi, remains one of the most formidable challenges affecting field pea (Pisum sativum var. arvense) production globally, leading to heavy yield losses. Methods: The present study was conducted at laboratory as well as net house of Department of Plant Pathology, Banda University of Agriculture and Technology, Banda during rabi of 2022-23 and 2023-24. Six Trichoderma isolates and seven fungicides were tested using dual culture method and poisoned food technique, respectively during 2022-23. On the basis of results obtained from in-vitro experiments which showed best effectiveness were used for in-vivo evaluation during 2023-24. Result: Among the bio-agent isolates, Trichoderma harzianum-3 (TH-3) showed the highest inhibition of Fusarium growth (66.09%) followed by T. harzianum-4 (TH-4) and T. viride-1 (TH-1) having 61.57 and 59.93 percent inhibition, respectively. Among the seven fungicides were tested using the poisoned food technique Carbendazim 50% WP and Tebuconazole + Trifloxystrobin were most effective, which completely inhibit fungal growth at 25 ppm concentrations and above. Compatibility tests showed that TH-3 was able to tolerate Azoxystrobin and Carboxin + Thiram (a combi-product), although some reduction in growth was noted. Despite this, TH-3 maintained its antagonistic activity. Field trials demonstrated that combining of TH-3 with Carboxin + Thiram reduced disease incidence by 68.33%, outperforming individual applications. The study suggests that integrating Trichoderma with selective fungicides offers an effective and sustainable approach for managing Fusarium wilt in field pea cultivation.