Determining the prominent factors contributing to the occurrence of sudden wilt in upland cotton (Gossypium hirsutum L.)

Abstract

The occurrence of sudden wilt problem in cotton in north India is increasing since the last one decade. Hence, to understand the factors responsible for sudden wilt, field data were collected from July to November during 2017-2018 and 2018-2019 from Rajasthan, Haryana, and Punjab. Among all, 29.7 per cent of cotton fields showed typical sudden wilting from September onwards during 2018-2019. In these fields, no deep ploughing, cotton-wheat-cotton cropping system more than the past 5 years, and early irrigation (before 30 DAS) was practiced. The soil EC and pH in these fields ranged between 2.5 to 4.5 dS/m and 7.6 to 7.9, respectively. The root depth in these fields was ranged between 100-200 mm with higher root density in the first 100 mm layer 21-50 per cent fields and 200-300 mm root depth in 50-67.5 per cent fields. These practices and soil health situations appeared to be the prominent factors contributing to the poor root development and occurrence of sudden wilt at the great grand growth stage of the cotton crop (125-160 DAS). Comparatively, sudden wilt was found to be more prominent in early maturing and high yielding Bt hybrids (BG-II) compared to Gossypium hirsutum varieties. This situation also enhanced the vulnerability of cotton crops to biotic problems such as root rot, nematodes, fungal foliar spots (71.4 %) and termites/root rot (28.6 %). Hence, to manage the sudden wilt problem and to achieve the potential yield, a large and deep root system must be developed as quickly as possible and shoot growth should be controlled before the plants enter the reproductive growth stage.