A composition comprising (a) a meltable solid matrix comprising (i) one or more solid hydrophobic substance, and (ii) one or more solid hydrophilic substance, and (b) distributed in said matrix, one or more encapsulation complex of a volatile cyclopropene compound encapsulated in a molecular encapsulation agent. Also provided is a method of treating plants or plant parts comprising placing said plants or plant parts and the composition of claim 1 into a container and allowing said plants or plant parts and said composition of claim 1 to remain together in said container for 1 day or longer.
