Vol. 12, Issue 8 (2023)

Pigeonpea (Cajanus cajan) is a vital legume crop susceptible to various pests and diseases, with Phytophthora blight, caused by Phytophthora drechsleri Tucker F. sp. cajani, emerging as a significant threat in India alongside other devastating pathogens. In this study, the efficacy of four non-systemic and systemic fungicides against Phytophthora drechsleri was evaluated through in vitro assays. For the non-systemic fungicides tested at concentrations of 1000 ppm, 1500 ppm, and 2000 ppm, significant inhibition of mycelial growth was observed, with increasing concentrations correlating with higher inhibition rates. Mancozeb exhibited the most pronounced inhibition across all concentrations tested, followed by Captan, Copper oxychloride, and Zineb. Similarly, systemic fungicides displayed notable inhibition of mycelial growth at concentrations of 500 ppm, 1000 ppm, and 1500 ppm. Metalaxyl + Mancozeb showed the highest inhibition, reaching 100% at 1000 ppm, followed by Cymoxanil + Mancozeb, Propineb, and Chlorothalonil.