Journal of Experimental Agriculture International

Aims: To correlate the population of the shoot and fruit borer, Earias spp., on okra with abiotic factors, such as minimum and maximum temperatures, relative humidity, and rainfall.

Study Design: The study design involved five separate plots, each measuring 2.25 x 1.5 m², with a row-to-row distance of 45 cm and a plant-to-plant distance of 30 cm.

Place and Duration of Study: The investigations were conducted during the Kharif season of 2022 at the Horticulture Farm, S.K.N. College of Agriculture, Jobner.

Methodology: The Pusa Bhindi-5 variety of okra was sown on 14th July 2022, following the recommended crop cultivation practices, excluding plant protection measures. Data on shoot and fruit borer, Earias spp., were recorded on five randomly selected plants from two weeks after sowing until the last fruit picking. Percent infestations were calculated based on the number of infested shoots and fruits per observation. A simple correlation was computed between the percentage of infestations in shoots and fruits, and meteorological parameters.

Results: The infestation of Earias spp. on the shoots of okra began on 15^th August (33^rd SMW) and peaked in the 38^th SMW with a maximum infestation of 12.04%. At that time, the minimum and maximum temperatures were 21.1°C and 33.1°C, respectively, and the relative humidity was 50%. Initially, the infestation on the fruits was low (2.84%), but it increased gradually, reaching 30.04% by the 42^nd SMW. The highest infestation rate occurred at a minimum temperature of 12.3°C, a maximum temperature of 33.4°C, and a relative humidity of 40%. The correlation studies revealed that the infestation of Earias spp. on the shoots of okra showed a non-significant correlation with all abiotic factors (maximum and minimum temperature, relative humidity, and rainfall). However, the infestation of Earias spp. on the fruit of okra, based on the number of infestations, showed a non-significant positive correlation with maximum temperature (r = 0.12). It also exhibited a significant negative correlation with minimum temperature (r = -0.90), as well as non-significant negative correlations with relative humidity (r = -0.46) and rainfall (r = -0.22) at the 5% level of significance.

Conclusion: The infestation of Earias spp. on okra shoots and fruits demonstrated a complex relationship with abiotic factors. Although the correlation with maximum and minimum temperatures, relative humidity, and rainfall was generally non-significant, a significant negative correlation with minimum temperature on fruit infestation was observed. These findings suggest that while temperature plays a key role in infestation dynamics, other environmental factors may not significantly influence the pest's population on okra.