grape grey mould

Symptoms

Brown soft rot of individual berries within a bunch, grey fuzzy sporulation after a few warm humid days, whole bunch collapse, vinegar/cider off-smell from infected fruit.

Easily confused with

• grape downy mildew

  How to tell them apart: Botrytis cinerea (grey mould / bunch rot) produces a dusty, mouse-grey, fuzzy mould that engulfs ripening berries and clusters in warm humid weather; affected berries turn brown, shrivel and split, and the velvety grey sporulation puffs up in dust clouds when touched. Plasmopara viticola (downy mildew) shows up first on leaves as yellowish translucent 'oil-spots' on the upper side with a dense, snow-white, downy felt on the LOWER leaf surface; on young green berries it forms a white downy bloom, while older infected berries turn leathery, brown-grey, dimpled and dull ('brown rot' / 'grey rot') with NO fuzzy white growth. Key tells: Botrytis grey + dusty and indifferent to leaf undersides; downy mildew is pure white + downy and tied to leaves with oil-spots and cool wet nights.

• European grapevine moth