Influence of weather parameters on the seasonal occurrence of paddy yellow stem borer (Scirpophaga incertulas)

Abstract

The experiment was conducted during the rainy (kharif), winter (rabi) and summer seasons of 2022–23 at College of Agriculture, V C Farm, Mandya, Karnataka to study the influence of weather conditions on the occurrence of paddy yellow stem borer [Scirpophaga incertulas (Walker)]. Rice (Oryza sativa L.) variety Jaya was selected for the experiment. Results found that the 37th and 39th Standard Meteorological Weeks (SMW) exhibited the highest infestation of dead heart (14.22%) and white ears (8.91%), respectively. This was associated with a noteworthy positive correlation with maximum temperature and a significant negative correlation with minimum temperature. Similarly, in rabi 2022, the 50th and 3rd SMW recorded the peak infestation of the dead heart (8.92%) and white ears (7.64%), respectively. These instances were linked to a significant positive association with morning relative humidity and bright sunshine hours, along with a significant negative association with minimum temperature and afternoon relative humidity. During summer 2023, the highest incidence of dead heart (29.26%) and white ears (21.74%) occurred in the 16th and 20th SMW, respectively. This was accompanied by a significant positive correlation with minimum temperature, rainy days, rainfall, and afternoon relative humidity. The peak infestation of dead heart and white ears was observed between 30–50 days after transplanting (DAT) and 80–100 DAT, respectively. To effectively manage this pest, it is recommended to adopt early sowing and timely interventions before reaching the peak, employing appropriate management practices. Therefore, continuous monitoring of the pest, utilizing future prediction models, and staying attentive to evolving weather conditions are essential components of effective pest management strategies.

Keywords

• Climate change, Seasonal incidence, Scirpophaga incertulas, Weather parameters