09-08-2013, 03:35 PM
Intensity and Epidemiology of Early blight of tomato (Alternaria solani) in Jammu region
ABSTRACT
Extensive survey of tomato fields conducted in summer season of 2011 revealed that disease was prevalent in all the locations and per cent disease intensity and per cent disease incidence varied from 21.66-34.13 and 10.48-18.56 per cent with overall mean of 27.73 and 13.31 per cent, respectively. The disease intensity (34.13%) and maximum disease incidence (18.56%) was recorded from Pangiari in Akhnoor block, whereas minimum per cent disease intensity of (21.66) was recorded from Gajansoo in Marh block and minimum disease incidence (10.65%) was recorded from Gango Chak in Marh block. Various weather parameters played a vital role in the development of disease and the disease initiated rapidly during 13th standard week and there was an increase in the development of disease on the 15th MSW, when the minimum and maximum temperature was 15.5o C and 29.8 and, minimum and maximum relative humidity was 41.9 and 70.4 per cent and rainfall 9.6 mm, respectively.The correlation of disease intensity with different weather parameters revealed that temperature (maximum and minimum) exhibited highly significant and positive correlation, while relative humidity (maximum and minimum) exhibited negative correlation, whereas rainfall had no effect on development of disease. Further, elimination of the variables from the best-fitted equations revealed that among the various abiotic factors, minimum temperature was mainly responsible for the development of early blight disease under field conditions.