Comparitive Evaluation of Different Fungicides against Phytophthora infestans (Mont.) de Bary. Causing Late Blight of Potato

Aim: Evaluation of various fungicides and their effectiveness at different doses against Phytophthora infestans, the causal pathogen of late blight disease of potato.

Study Design: Descriptive statistics was used and each treatment was replicated thrice using complete randomize design.

Place and Duration of Study: Department of Plant Pathology, CSA University of Agriculture & Technology, Kanpur, Uttar Pradesh, India in October 2016.

Methodology: We followed “Food Poison Technique” [1] to find out the relative efficacy of various fungicides in Inhibiting the growth of pathogen.

A small piece of infected leaf from border of sporulating lesion along with some healthy green tissue was cut and Sterilized. These small pieces were then placed on tomato extract based media which was previously poured in sterilized Petri plates. As soon as the mycelia growth is noticed around the bits, the pathogen was purified by hyphal tip culture method. Mycelial bits of 5 mm from the pure culture were placed on the tomato extract media which was incorporated with various fungicides at different doses.

Results: Among the five different fungicides Metalaxyl inhibited the mycelial growth upto 99.2% over the control at 300 ppm concentration followed by 98.44% inhibition at 300 ppm concentration mancozeb at 400 ppm concentration inhibited the radial growth upto 96.62% followed by 95.27% inhibition at 300 ppm concentration.

Conclusion: This method can be used for Analysing the efficacy of various fungicides against different pathogens within a very short period of time.