Environmentally friendly management of Monosporascus root rot/ vine decline disease of muskmelon with beneficial rhizosphere microorganisms

Monosporascus root rot/ vine decline (MRR/VD) disease caused by the ascomycete fungus, Monosporascus cannonballus, is a major limiting factor to muskmelon (Cucumis melo L.) cultivation in Oman. The fungus infects roots of melon plant and causes root necrosis, severe stunting and death of muskmelon plants. The intensive and continuous cropping of melon favour the buildup of pathogen inoculum in the soil. Control of this pathogen is very difficult as it produces thick-walled ascospores, which survive in the soil and on plant debris and emerge as inoculum and cause disease during the following season. Presently, there are no commercial melon cultivars that are resistant or highly tolerant to MRR/VD. Few soil fumigants are found effective in the control of this disease. But the harmful effects of synthetic fungicides on the environment and their escalating cost, development of resistant mutants of pathogens and frequent breakdown of resistant cultivars strongly demand a sustainable and an alternative approach for controlling this disease. Biological control method, by using naturally occurring non-pathogenic, antagonistic microorganisms has been considered as an environmentally safe and sustainable alternative to the use of synthetic chemical fungicides for the management of soilborne diseases. The primary aim of the proposed research is to isolate native bacterial antagonists from the rhizosphere of melon and to develop a biopesticide formulation for the control of MRR/VD disease of melon under field conditions.