Bio-efficacy of copper sulfate (Tribasic) against downy mildew disease of cucumber

Abstract

Downy mildew disease (DMD) of cucumber is destructive in nature and reduces fruit yield. Fungicides were used to control DMD but still DMD occurs. Hence, for the good alternative fungicide to control DMD, field experiment on efficacy of copper sulfate (tribasic) 345g/l SC against DMD was conducted in rabi season of 2016-17 and 2017-18. There were 7 treatments with six fungicides and control. Observations on per cent disease index (PDI), fruit yield and phytotoxicity of fungicides on cucumber were recorded. In 2016-17, copper sulfate (tribasic) 345g/l SC @ 4000 ml/ha reduced PDI maximally (18.78 %) followed by copper sulfate (tribasic) 345g/l SC @ 3000 ml/ha (19.67%) where as in untreated control treatments mean PDI was 42.06%. In 2017-18, copper sulfate (tribasic) 345g/l SC @ 4000 ml/ha reduced PDI maximally (19.13 %) followed by copper sulfate (tribasic) 345g/l SC @ 3000 ml/ha (20.29%) where as in untreated control treatments mean PDI was 42.88%. In 2016-17 and 2017-18, copper sulfate (tribasic) 345g/l SC @ 4000 ml/ha treated plants produced higher yield of cucumber fruits (15.50 t/ha, 17.32 t/ha) over other formulations. Copper sulfate (tribasic) 345g/l SC with formulation of 2000 ml/ ha and copper sulfate (tribasic) 345g/l SC with formulation of 4000 ml/ ha were not toxic to cucumber plant in rabi season of 2016-17 and 2017-18. The results concluded that use of copper sulfate (tribasic) 345g/l SC with formulation of 4000 ml/ ha resulted in reduced PDI and improved yield.