Abstract: Compositions containing one or more tyrocidines, tryptocidines, phenycidines and/or gramicidin S, or derivatives and analogues thereof, are described for controlling antimicrobial growth on plants, plant material or plant growth media, and methods for controlling or preventing the growth of microbial pathogens, and in particular fungal pathogens, on plants, plant parts and plant material are described herein. The active agents used to control these pathogens are tyrocidines, tryptocidines, phenycidines and/or gramicidin S, or derivatives, analogues or modifications thereof.