Role of Weather Parameters on Development of Target Spot of Cotton caused by Corynespora cassiicola

Author: Dharmesh K. Davara, Iteshkumar B. Kapadiya and Amit M. Polara

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Abstract

The corynespora target spot caused by Corynespora cassiicola is a severe constraint in cotton production and the disease intensity has been increasing day by day for the last few years in India due to changes in the environment. The field experiment was carried out to understand the development of target spot on cotton with respect to weather conditions during Kharif 2023 at Cotton Research Station, JAU, Junagadh and Oilseeds Research Scheme JAU, Manavadar. Correation with weather factor indicated that significantly positive correlated with minimum temperature (0.61*) and significant negative correlated with evaporation (r=-0.58*). Results showed that multiple regression equation was fitted to the data and the equation arrived for the weather parameters indicated that increase in one unit of minimum temperature, evening relatively humidity and sunsine hour, the per cent disease intensity increased by 2.09, 0.80 and 4.00 units, respectively. While when there was increased in one unit of maximum temperature, evening relatively humidity, rainfall, evaporation and rainy days, the per cent disease intensity decreased by 0.17, 1.43, 0.03,7.51 and 7.51 units respectively. The R2 values indicated the combination of eight weather factors accounted for variation in disease development. R2 value close to 1 proved the goodness and feasibility of model at Junagadh and when there was increased one unit maximum temperature, morning relatively humidity, evening relatively humidity, rainfall, sunsine hour and evaporation, the per cent disease intensity increased by 1.70, 0.14, 1.22, 0.007, 4.08 and 6.56, respectively. While when increased in one unit of minimum temperature and rainy days, the per cent disease intensity decreased by 1.20 and 1.31 units respectively at Manavadar. Using these variables, the regression models were developed to foretell the relationship between disease severity and weather variables. Stepwise regression equation obtained Y= -41.22 + 3.56 Tmin R2=0.4670 and Y= -107.52+1.07 RH II + 4.95 SSH + 7.56 Evap. R2=0.8590 at Junagadh and Manavadar, respectively

Keywords

Corynespora cassiicola, cotton, weather parameters, correlation and regression

Conclusion

The effect of weather parameters on disease development was studied two location Kharif 2023. Prevailing moderate temperature of 25-30°C, high relative humidity (>90%) with intermittent rainfall were essential for disease establishment observed in two location. Disease initiation was observed in 35 and 32 standard meteorological week which required weather parameters for disease development at Junagadh and Manavadar, respectively

References

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How to cite this article

Dharmesh K. Davara, Iteshkumar B. Kapadiya and Amit M. Polara (2024). Role of Weather Parameters on Development of Target Spot of Cotton caused by Corynespora cassiicola. Biological Forum – An International Journal, 16(8): 211-214.