Management of grape anthracnose under field condition

Abstract

Grape (Vitis vinifera L.) is an important commercial fruit crop worldwide, however, its productivity and fruit quality are severely constrained by fungal diseases such as downy mildew (Plasmopara viticola), powdery mildew (Erysiphe necator), anthracnose (Colletotrichum gloeosporioides) and Botrytis bunch rot (Botrytis cinerea). Among these, anthracnose caused by Colletotrichum gloeosporioides popularly known as Bird’s Eye Spot is highly destructive, particularly in tropical and subtropical regions. The present study conducted on the management of grape anthracnose under field conditions during back pruning (April) and fore pruning (October). Among the treatments tested, fluopyram 17.7% + tebuconazole 17.7% SC (T11) consistently recorded the lowest disease severity of 24.63 with highest reduction over control of 51.84 percent during back pruning (April). During fore pruning (October), fluopyram 17.7% + tebuconazole 17.7% SC (T11) recorded the lowest disease severity of 12.71 PDI and highest reduction over control of 53.15 percent. Which followed by copper sulphate 47.15% + mancozeb 30% WG (T10) (26.25 to 13.55% PDI). Other effective fungicides included tebuconazole 25.9% EC (T8) (27.42 to 13.96% PDI) and thiophanate methyl 70% WP (T6) (27.83 to 14.48% PDI), while mancozeb 75% WP (24.63 to 12.71% PDI) was least effective. The untreated control exhibited the highest disease severity (37.95 to 17.95% PDI). Maximum grape yield was recorded with T11 (30.75 t/ha), followed by T10 (29.85 t/ha) and T8 (29.00 t/ha), fluopyram 17.7% + tebuconazole 17.7% SC at 0.6 ml/L and copper sulphate 47.15% + mancozeb 30% WG at 2.0 g/L treatments achieved the highest economic returns with a B:C ratio of 3.33. Overall, treated plots significantly reduced disease severity and improved yield and profitability compared to the untreated control.