Experiments on the Control of Tomato Leaf Mould (Cladosporium Fulvum) By Fungicides and Fumigants

Abstract

Summary.1. Experiments have been made on the control of tomato leaf mould (Cladosporium fulvum) by fungicides and fumigants. The results showed that most fungicides gave better control of the disease when Agral I was added as a spreader instead of saponin. Effective control was obtained on pot plants sprayed with ammonium copper carbonate, colloidal sulphur A, and salicylanilide. Preliminary trials on commercial nurseries showed that ammonium copper carbonate and colloidal sulphur A were suitable fungicides for use on glasshouse tomato crops. Further work showed that ammonium copper carbonate was useful for spraying diseased tomato crops.2. The disease was controlled by the fumigants ethylene dibromide, quinone, and thymol, in laboratory experiments, and by quinone in trials made in a small glasshouse. Further work is necessary to ascertain if quinone fumigation is practicable for the control of tomato leaf mould in large glasshouses.3. Fumigation with Campbell's sulphur vaporiser protected only the upper side of the leaves from the disease and also failed to kill the spores on the under side of diseased leaves. Experiments made to determine on which leaf surface infection occurs under natural conditions were not successful, but inoculation tests showed that infection may occur on either side of the leaf.4. It has been shown that large empty glasshouses may be practically freed from infection by fumigation with formaldehyde or sulphur dioxide.