Field Survey and Assessment of Fusarium Wilt Incidence in Cotton (Gossypium spp.) in Hanumangarh District of Rajasthan, India

Cotton (Gossypium spp.) is a vital commercial crop cultivated worldwide for its natural fibre and seed. Among the various biotic stresses affecting cotton production, Fusarium wilt, incited by the soil-borne fungus Fusarium oxysporum f. sp. vasinfectum (FOV), is one of the most devastating diseases, often leading to considerable economic losses. The pathogen is known for its long-term survival in the soil through chlamydospores and its ability to persist in association with the roots of susceptible, resistant, and non-host plants, as well as within infected seed. In the present study, a systematic survey was conducted in major cotton-growing regions of Hanumangarh district of Rajasthan to assess the incidence of Fusarium wilt. The maximum disease incidence (28.38%) was recorded in Pilibanga (loamy soil), followed by 27.71% in Goluwala (loam), while the lowest incidence (7.82%) was observed in Motsar, which is characterized by loam soil. Morphological observations revealed that microconidia were produced in greater numbers compared to macroconidia. Chlamydospores were found to be abundant, occurring both terminally and intercalarily. The virulent isolate FTH34 (Fatehgarh), the dimensions of macroconidia, microconidia, and chlamydospores were 38.95x6.26μm, 14.67x5.26μm, and 11.88x10.06μm, respectively.