Nigel Cattlin / Powdery mildew (Erysiphe betae) fungal disease on the leaf of sugar beet, Champagne region, France, September

Nigel Cattlin / Powdery mildew (Podosphaera leucotricha) fungal disease infection with ascocarps on an apple twig, New York, USA, September

Nigel Cattlin / Powdery mildew (Blumeria graminis) mycelium and cleistothecia and brown leaf rust (Puccinia triticina) pustules on a wheat leaf

Nigel Cattlin / Powdery mildew (Uncinula necator) fungal disease infection causing discoloured and split white wine grapes, Greece

Nigel Cattlin / Powdery mildew (Microsphaera berberis) white mycelium on the upper surface of a Mahonia leaf

Nigel Cattlin / Photomicrograph of wheat leaf or brown rust (Puccinia triticina) sporulating pustules and spores with powdery mildew on a wheat leaf

Nigel Cattlin / Powdery mildew (Podosphaera pannosa) fungal infection on rose leaves, Berkshire, September

Nigel Cattlin / Powdery mildew (Blumeria graminis) fungal disease on an aborted ear and flagleaf on wheat plant ears

Nigel Cattlin / Hypersensitive reaction to powdery mildew (Blumeria graminis) causing necrotic lesions on barley leaf

Nigel Cattlin / Powdery mildew (Erysiphe graminis) infection on wheat crop coming into ear, white pustules on the stem and lower leaves

Nigel Cattlin / Powdery mildew (Erysiphe graminis) infection on wheat crop coming into ear, white pustules on the stem and lower leaves

Nigel Cattlin / Powdery mildew, (Podosphaera pannosa) fungal disease on rose leaves, Rosa 'American Pillar', Berkshire, England, UK, May