Study of area under disease progressive curve (AUDPC) on collar rot disease of Indian bean caused by Sclerotium rolfsii in South Gujarat

Collar rot of Indian bean caused by Sclerotium rolfsii Sacc. is exerting a major threat on Indian bean growers in South Gujarat. The initiation of the disease was first noticed after 10 and 15 days of sowing in susceptible variety GNIB-21 which was grown on 11st Oct. and 12nd Oct. of 2017-18 and 2018-19, respectively. Since then, there was linear progress of the disease during both the seasons. The disease appeared 8.47% at initial stage 44th SMW and reached highest 246.99% at maturity 3rd SMW during 2017-18. In 2018-19, disease appeared 9.62% at initial stage 44th SMW and reached highest 26.76% at maturity 3rd SMW. However in pooled of two years, the first symptom of collar rot was recorded on 44th SMW (9.0%) and reached to 3rd SMW (255.40%). Correlation coefficient study between weather parameters and AUDPC indicated that all the parameters jointly played an important role in the development of collar rot disease. Moreover, morning and afternoon 5 cm and 10 cm depth soil temperature, soil moisture 5 cm and 10 cm were found to play important role in the disease development. Co-efficient of determination, R2-value i.e., 0.646, 0.954 and 0.860 percent were found high during 2018, 2019 and pooled of two year, respectively. These high R2-value indicating a strong association between AUDPC to weather parameters.