Forecasting of rice blast disease severity in West Bengal, India based on PDI values and Cumulative logit model

Abstract

Blast disease of rice is generally considered the most important rice disease worldwide for its extensive distribution and also for its destructiveness under favourable environmental conditions. The disease incidence and development in time scale in relation to different parameters can be predicted through epidemiological study. Plant disease forecasting is a management system used to predict the occurrence or change in severity of plant diseases. A field experiment was conducted for three consecutive year in kharif season at two different sampling sites in North 24 Parganas, W est Bengal to find out the effect of meteorological factors on severity of blast disease. The aim of the present study is to prepare models for predicting the severity, with the aim of helping to prevent or at least mitigate the spread of blast disease. For forecasting of disease severity, the comparative study of three years meteorological data was made. The congenial weather conditions for the infection of blast disease pathogen viz. Pyricularia oryzae was recorded. The crop phases during which rapid development of disease takes place were also recorded. Multiple regression analysis (MRA) of PDI values with the age of the plant, respective pathogenic spore concentration and with five meteorological parameters was performed. From step down equation, it was found that if the age of the plant and airborne spore concentration, RH and rain fall are increased, disease severity also increases significantly in both the seasons. From Cumulative logit model the covariates with their odds ratios were determined. From all the findings it can be concluded that among meteorological parameters high relative humidity, rain fall and comparatively low temperature are the common factor for disease incidence and severity.

Influence of meteorological factors on atmospheric fungal spores over crop canopy of rice in West Bengal, India with reference to major fungal diseases

“…Ustilaginoidea virens spore was first trapped in the air from 3 rd to 4 th week of October. Susceptible growth phases for false smut disease was from early ripening to preharvest period (Saha, 2022). Lara et al (2005) studied climatic conditions of Pyricularia oryzae spore concentration and leaf symptoms in rice crop.…”

“…To fill up this knowledge gap, present study was designed to investigate the occurrence of fungal spores in the air over rice field in West Bengal with reference to major fungal diseases of rice. The aero-mycological data over crop field are therefore indispensable to understand the disease epidemiology, control and establishing the forecasting probabilities (Saha, 2022).…”

A review on important diseases of rice in West Bengal

“…According to reports, the blast in South India in 1920 caused loss of about 80% to the crop (Saha 2022) [14] .…”

“…In severe infection nodes and neck portion become blackish in colour, rots and grains are damaged or lost. Saha (2022) [14] conducted a comparison study using three consecutive years' weather data of West Bengal. It was noted that the weather was ideal for Pyricularia oryzae, the pathogen that causes blast disease.…”