Field and In Vitro effectiveness of fungicides against gummy stem disease,sudden death and leaf blight, the emerging syndromes of bottle gourd

Gummy stem, sudden death and leaf blight diseases are newly emerging, concurrently occurring, serious problems of bottle gourd in northern India. Due to the unavailability of resistance sources against these diseases, chemical management is the only viable option against this disease complex. Bio-efficacy of systemic and non-systemic fungicides as foliar, soil drench and as combination of foliar with soil drench is reported against these three diseases under in vitro as well as field conditions. Under in vitro, conditions carbendazim was the most effective against Fusarium verticillioides (ED₅₀ 0.25 μg mL⁻¹) and Fusarium oxysporum (ED₅₀ 0.21 μg mL⁻¹), the causal agents of gummy stem disease and sudden death respectively, whereas, combi-product of trifloxystrobin + tebuconazole (1:2) was the most effective against Lasiodiplodia theobromae (ED₅₀0.28 μg mL⁻¹) incitant of leaf blight. Under field conditions, three applications of carbendazim 50 WP @ 0.2 per cent as soil drench around the vine base along with foliar application of tebuconazole 25 EC @ 0.1 per cent concentration at fortnightly interval starting from last week of July proved to be the most effective against gummy stem disease and sudden death. Against leaf blight, three foliar applications of propiconazole 25 EC @ 0.1 per cent were the most effective.