In-vitro evaluation of novel fungicides against leaf spot and flower blight of marigold by different techniques

Leaf spot and flower blight caused by Alternaria zinniae is serious disease of marigold causing yield loss of 50-60 % in crop. Many previously used fungicides showed resistance against the pathogen. So, the present investigation was carried out with an objective to study the efficacy of new fungicides available in the market using poison food technique, well diffusion technique and disc diffusion technique. Three fungicides such as azoxystrobin +tebuconazole, tebuconazole + sulphur, Metalaxyl were evaluated at the concentration of 0.1%, 0.15%, 0.2% respectively. The present investigation revealed that Azoxystrobin + Tebuconazole recorded maximum mycelial growth inhibition of 96.85% followed by Tebuconazole + Sulphur 96.40% and Metalaxyl of 95.50% in poison food technique. Similarly, Azoxystrobin + Tebuconazole showed the highest inhibition of mycelial growth (88.10%), followed by Tebuconazole + Sulphur (86.36%), and Metalaxyl (84.38%) in well diffusion technique. In a same manner Azoxystrobin + Tebuconazole showed the highest inhibition of mycelial growth (77.73%), followed by Tebuconazole + Sulphur (75.10%), and Metalaxyl (72.25%) in disc diffusion method. Further the effectiveness of new fungicides may be tested under field condition against Alternaria zinniae.