Further studies on copper sulphate-lime ratios in Bordeaux mixture

Abstract

Studies on the effects of varying the proportion of lime in Bordeaux mixlure for potato spraying were started at Charlottetown, P.E.I., in 1943. This is the second paper reporting on these studies and covers the work of 1947 and 1948. These two years were quite antithetic in respect to meteorological and disease conditions, yet, in both seasons, the highest yields were obtained from plots treated with Bordeaux mixture having a copper sulphate-lime ratio of 2:1. Late blight tuber rot data from 1943 to 1948, inclusive, indicate that a low-lime Bordeaux mixture is more effective than a high-lime one in controlling tuber rot, the ratio of losses from plots treated with 4-1-40, 4-2-40, 4-3-40, and 4-4-40 Bordeaux mixture being 1:3:4:6.