COMPARATIVE TRIALS OF COPPER, DITHlOCARBAMATE AND ORGANO-TIN FUNGICIDES FOR POTATO BLIGHT CONTROL IN LINCOLNSHIRE,.

This article provides information on comparative trials of copper dithiocarbamate and organo-tin fungicides for potato blight control in Lincolnshire, England from 1958-1961. In trials at three centers in 1958, three spray applications proved inadequate for the control of blight but the gain from spraying was significantly better with zineb than with copper oxychloride. With 6 to 8 applications at weekly intervals, in the three following years, copper, zineb, maneb and triphenyltin acetate gave about equal control of the disease on the foliage, but both in the dry, hot season 1959, when the blight attack was very late, and also in the wet season 1960, copper oxychloride gave a lower gain in yield from spraying than the other three fungicides at a number of the centers, probably due to phytotoxic effects .