Integrated Study on the Etiology and In-Vitro Fungicidal Management of False Smut Disease in Rice

Rice is the second most valuable food grain and cash crop in Pakistan after wheat and cotton, serving as a vital source of food and income across Asia. Despite its importance, Pakistan's per-acre rice yield is significantly lower than global averages, primarily due to biotic stresses such as plant diseases. Among the nearly 50 diseases affecting rice globally, false smut, caused by Ustilaginoidea virens, poses a serious threat to rice production and farmer livelihoods. To assess the incidence and management of false smut in southern Pakistan, a survey was conducted in key rice-growing areas including Khorwah, Kario Ganhwar, and the surroundings of Badin city. Disease incidence ranged from 24.00% to 46.00%, with the highest incidence observed in Khorwah (46.00%) and the lowest in Badin (24.00%). Diseased samples were collected for pathogen isolation using tissue culture techniques, and fungal identification was based on morphological features. Four fungal species were identified: Ustilaginoidea virens (45.12% frequency), Penicillium (28.31%), Pyricularia oryzae (18.57%), and Aspergillus (8%). U. virens emerged as the predominant pathogen based on frequency and colony characteristics. For disease management, six fungicides were evaluated using the food poisoning method at concentrations of 500, 1000, and 1500 ppm. Among them, Topsin-M and Nativo demonstrated complete inhibition of pathogen growth at 1500 ppm, making them the most effective. Aliette and Romeo showed moderate effectiveness, while Melody duo and Copper oxychloride were less effective across all concentrations. The study concludes that Topsin-M and Nativo are highly effective in controlling false smut in rice and should be recommended for integrated disease management strategies in affected regions. These findings provide a practical approach to mitigating yield losses caused by this destructive pathogen