Forecasting late blight of potato in Punjab using jhulsacast model

Late blight of potato caused by Phytophthora infestans can cause huge loss to potato crop. Forecasting appearance of the disease in advance can help potato growers take timely action to prevent the disease and reduce the losses. Weather data collected in Punjab for 15 years (1997–2012) was analyzed to calibrate ‘JHULSACAST’ -a model developed to forecast late blight in western Uttar Pradesh - to make it suitable to forecast appearance of late blight in Punjab. The model specifies that 7 day moving sum of RH ≥ 85% for at least 90 hr coupled with a 7 day moving sum of temperature between 7.2 to 26.6°C for at least 115 hr would predict appearance of late blight within 10 days of satisfying the conditions. The modified model was found suitable to predict appearance of late blight under Punjab conditions.