INFLUENCE OF ENVIRONMENTAL FACTORS ON THE DEVELOPMENT OF POTATO BLACKLEG DISEASE.

Climatic conditions play a crucial part regarding the development of blackleg caused by Pectobacterium atrocepticum (Pa), which is one of the major threats the potato industry faced. These factors affect the stage of growth, host susceptibility, succulence, vigor, survival, rate of multiplication, direction of pathogen dispersion, rate of spore penetration and germination. In the present experiment, effect of these environmental variables like maximum and minimum temperature (max and min T), relative humidity (RH), rainfall (RF), and wind speed (WS) on disease development were studied. Significant positive correlation was observed for all twenty-five varieties and a multiple regression model (Y = + 24.382 + 0.3592X1 + .0970X2-0.2551X3 + 1.982X4) based on the two-year study was developed to find out the relationship between environmental parameters and disease projection. Goodness of model was indicated by coefficient determination value (97.5%). Correlation of these environmental factors on the development of disease on twenty-five potato varieties during 2018, 2019 was done. Significant positive correlation was observed on all twenty-five varieties. In conclusion, it was established that environmental factors, including max. T (28 °C), min. T (15 °C), RH 70%, and WS 3.5 Km/h were conducive for the development of blackleg. Current study would be helpful for researchers in designing better disease management strategies under changing climatic conditions in the future. [ABSTRACT FROM AUTHOR]