Population Fluctuation of Okra Shoot and Fruit Borer, Earias vittella (Fabricius) in Relation to Abiotic Factors

Abstract

Field investigations were conducted during Kharif 2022 and 2023 study aimed to determine the seasonal population fluctuation of the okra shoot and fruit borer Earias vittella on okra variety Prabhani Kranti at the Student’s Instructional Farm (SIF), Chandra Shekhar Azad University of Agriculture and Technology, Kanpur, Uttar Pradesh, India. The seasonal incidence study revealed that Earias vittella infestation was closely correlated with prevailing abiotic factors including temperature, relative humidity, rainfall and wind speed. Shoot damage initiated in the 30th Standard Meteorological Week (SMW) in both years (1.3%) and peaked in the 33rd SMW in 2022 (9.9%) and 34th SMW in 2023 (9.1%). In 2023, shoot damage showed significant positive correlations with minimum temperature (r = 0.535), relative humidity (r = 0.487) and wind speed (r = 0.729) indicating that these parameters greatly influenced pest incidence. Fruit infestation began slightly later, in the 34th SMW (2022) and 33rd SMW (2023), with peaks of 14.4% (38th SMW, 2022) and 12.0% and 11.2% (bimodal peaks in 37th and 40th SMWs, 2023). However, correlations between fruit damage and abiotic factors were generally weak and non-significant across both years. The larval population trend closely mirrored fruit infestation patterns, peaking at 4.7 larvae/5 fruits in both years during 38th (2022) and 39th SMW (2023). Despite the absence of significant correlations with abiotic parameters, a positive trend was observed with maximum temperature and relative humidity, especially in Kharif mid-season. Thus, these findings offer valuable insights for formulating climate-resilient pest management strategies to ensure sustainable okra cultivation in central Uttar Pradesh.