A method of killing fungal pathogens of plants comprising the application of an effective amount of 1,3,5-Triazinane-2,4,6-Trithione (TMT) to a plant. Particularly, the TMT is in an aqueous solution in a concentration range of 0.01% w/v to 0.1% w/v. In one embodiment the aqueous solution is applied to the plant by foliar spray. In another embodiment aqueous solution containing the TMT is mixed with zeolite or composite material including zeolite.