NEW MATERIAL:A clathrate compound derived from 5-methyl-s-triazolo(3,4-b) benzo-thiazole (abbreviated as TC hereinafter) and cyclodextrin.

EXAMPLE: A clathrate compound from TC and β-cyclodextrin.

USE: Antifungal agent or solid agricultural chemical composition with stabilized activity. Further, a mixture of insecticidal organophosphorus compound (abbreviated as OP herein after) bearing at least one of methoxy or methylthio group directly connecting with phosphorus atoms with the chlathrate compound of TC and cyclodextrin develops synergism to be remarkably stabilized and maintain a high level of antifungal activity.

PREPARATION: The reaction of TC with a cyclodextrin such as β-cyclodextrin is conducted in a solvent such as methanol or acetone to produce the titled compound.