Management of late blight of potato through inorganic copper compounds under organic system

Abstract

Attempt has been made to evaluate three different copper compounds viz. copper hydroxide copper sulphate and copper oxy-chloride against late blight of potato under single spray schedule. All the copper fungicides gave significantly effective control against the disease and were able to delay the disease appearance by three days in comparison to the unsprayed control. However, none of them able to arrest the disease incidence and intensity below 50 % as recorded at 15 days after first appearance of symptoms. Lowest disease intensity (77.77%) with comparatively high healthy tuber (4.48t/ha) was recorded in plots sprayed with copper hydroxide @ 0.2 % as one prophylactic spray at the time of canopy closure subsequent two at seven days intervals.