Effects of triadimefon on the ultrastructure of rust fungi infecting leaves of wheat and broad bean ( Vicia faba)

Abstract

The effect of triadimefon on the fine structure of Uromyces vicia-fabae infecting leaves of broad bean, and brown rust caused by Puccinia recondita infecting wheat leaves, was studied using transmission electron microscopy. Changes were induced in intercellular mycelia following both root and leaf application of the fungicide. Incomplete and multiperforate septa occurred, and extensive wall thickening was found, often almost completely blocking the hyphae. Triadimefon vapour was shown to have a similar effect on intercellular hyphae of P. recondita as did direct application. The changes are discussed in relation to the mode of action of triadimefon and its effect on sterol biosynthesis.