A b s t r a c t A r t i c l e I n f oTrianthema portulacastrum L., commonly known as desert horse purslane is a member of Aizoaceae, interfere with many economic crops and treated as one of the serious weed in India and around the world. It is a native plant of South Africa but widely distributed in India, Sri Lanka, Pakistan and many parts of the world. It has become a noxious weed due to competition for yields in many crops and causing significant reduction in the yield. For instance, its infestation in cotton, maize and direct-seeded rice reduce crop yields by 32-60%, up to 60-70% infestation of this weed has been reported in pigeon pea and soybean fields and 80-90% in maize and brassica fields. The common weed control methods such as cultural practises, mechanical and herbicide treatments does not consider for the effective management of this weed due to their failures. Recently, the successes of Biological control agents over many herbs and alien weeds attracted researchers with their eco-friendly tactics. Therefore, a systematic field study was conducted for preliminary screening of natural enemies against horse purslane weed which would be an effective biocontrol agent after extensive work. An ascomycetes fungus, Gibbago trianthemae Simmons was isolated from parasitized leaves of horse purslane and the identity was confirmed by relevant literature and the biocontrol potential of the pathogen evaluated.