Wound dressings for the prevention of silver-leaf in fruit trees caused by Stereum purpureum (Pers.) Fr

Several fungicides and proprietary tree wound dressings were compared for inhibition of spore germination and growth of Stereum purpureum (Pers.) Fr. in vitro, and for protection of fruit tree wounds. Laboratory, glasshouse, and field experiments all showed that a proprietary bitumen water emulsion alone was ineffective in protecting tree wounds from becoming infected by S. purpureum, but in combination with 1 % w/w captafol or thiram it gave better protection. In laboratory and glasshouse tests, wound dressings based on polyvinyl acetate with or without added fungicide performed better than bitumen emulsion with added fungicide, and they were easier to apply consistently under field conditions. None of the materials investigated if applied to wounds when trees were dormant caused phytotoxic reactions.