Over eighty compounds have been assayed for fungistatic activity.Fusarium graminearum, Penicillium digitatumandBotrytis alliiwere used as test organisms. The preliminary results suggest that fungistatic activity is associated with the tendency of the substituents to withdraw electrons from the double bond. Nitroethylenes and fumarates are, for example, fungistatic. Tetraiodoethylene has high activity but this can hardly be attributed solely to the withdrawal of electrons from the double bond by the iodine atoms.