Response of okra varieties to okra leaf curl viral disease (OLCVD) in relation to environmental conditions

Abstract

Okra (Abelmoschus esculentus L.) is an important vegetable crop used for nutritional, economic and medicinal purposes, grown in the tropics and subtropics regions. However, its production is severely affected by viral diseases, particularly okra leaf curl disease (OLCD), which is transmitted by whitefly (Bemisia tabaci). In the present study, six varieties of okra (Tulsi, Pooja, Durgah, Sabzpari, Sarahariya and Ramaan Kirshna) were tested for their response to okra leaf curl viral disease (OLCVD) under various environmental conditions at Shahpur, Peer Khathi and Tando Adam during Rabi and Kharif seasons. The results showed that DI % and severity varied among varieties, locations and seasons. The variety Tulsi showed no DI % and severity at all locations during both seasons, indicating strong resistance. In contrast, other varieties showed different levels of susceptibility, with the highest DI % recorded during the Rabi season, particularly at Peer Khathi. Disease severity was also higher in Rabi (score 3) compared to Kharif (score 1). The population of whitefly varied among locations and seasons and was higher in susceptible varieties, contributing to increased disease spread. Correlation analysis revealed that relative humidity and minimum temperature had a highly significant positive correlation with DI % and severity during the Rabi season, while their effect was mostly non-significant in Kharif. Maximum temperature showed weak to moderate and mostly non-significant effects.