Movement, persistence and performance of fungitoxicants applied as pruning wound treatments on apple trees

The systemic fungicides triadimenol, fenpropimorph, furmecyclox and carben-dazim, applied to pruning wounds as solutions in a non-aqueous solvent containing N-methyl–2-pyrrolidone moved predominantly towards the trunk. Coriolus versicolor, introduced deliberately, moved both proximally and distally irrespective of whether it was introduced in the dormant or growing season. Natural resistance to damage by chemical or C. versicolor appeared to be greater in the growing than in the dormant season and was inhibited when a cationic surfactant was used to aid penetration of fungitoxicant into the wood. Against C. versicolor the non-systemic fungicide captafol was ineffective, furmecyclox or fenpropimorph gave some protection and triadimenol was very effective. Carbendazim, although inactive against wood-rotting basidiomycetes, moved extensively within the wood and persisted well, and so could be an effective treatment for ascomycete pathogens. It also stimulated callus formation. The mercuric oxide preparation Santar was effective in these experiments and also stimulated callus formation.