On some estates in Malaya the incidence of Marasmius bunch rot reaches serious proportions through causes other than poor sanitation or pollination. In such areas fungicidal sprays may be of value in both therapy and prophylaxis. In laboratory tests, using the paper disc diffusion and liquid culture methods, 32 fungicides were tested for activity against Marasmius palmivorus to provide an indication of promising formulations for field trials. A number of compounds showed strong inhibition of fungal growth in both series of tests, and amongst these the organo-mercury preparations were outstanding, especially Antimucin WBR. Other promising fungicides included Fylomac 90, Seprisan, Hyamine, Izal, Thiram and PCNB. In field trials in which Antimucin WBR and Verdasan were used for treatment of partially-infected immature bunches, these fungicides checked disease development, with a significant reduction in losses through disease. The value of fungicidal sprays formerly recommended in estate practice, and their potential value in prophylaxis, are discussed.