Significance of Sowing Dates and Meteorological Parameters on Severity of Stem Gall of Coriander Caused by Protomyces macrosporus

Abstract

Background: Coriander (Coriandrum sativum L.) belongs to family Apiaceae is generally grown in winter season as a main crop in India. Stem gall of coriander caused by Protomyces macrosporus L. is a serious disease damaging all aerial plant parts. Under favourable ecological conditions, the disease may lead losses to the extent of 100 per cent therefore it is necessary to investigate the epidemiology of the disease to devise suitable remedial measures Methods: The field experiment was conducted during Kharif season of 2018 with two varieties to study the effect of different meteorological parameters on stem gall of coriander at different sowing dates (1st week of November to 1st week of December). The stem gall severity was recorded at weekly intervals from the start of its incidence. Result: The disease severity was lowest (5.42%) in the variety DH-36 sown in 3rd week of November and maximum disease severity (11.88%) was observed in variety DH-228 sown in 1st week of December. The quantitative relationship between the disease severity and weather variables at different dates of sowing for two varieties was obtained by performing correlation analysis. The temperature (maximum and minimum) and sunshine hours had positive correlation with per cent disease intensity, while relative humidity (morning and evening) and remaining weather parameters were non-significant at each dates of sowing but correlated with the disease intensity.