fusarium head blight / scab

Symptoms

Premature bleaching of individual spikelets during/after flowering, pinkish-orange fungal growth at base of bleached spikelets in humid weather, shrivelled chalky-white kernels (tombstones) at harvest.

Easily confused with

• ergot of rye + cereals

  How to tell them apart: Fusarium graminearum (Fusarium head blight): one or more spikelets, or a whole section of the ear, bleach to a pale straw colour while the rest of the head stays green; in humid weather look for salmon-pink to orange spore masses (sporodochia) at the base of the glumes and along the rachis. Infected grains shrivel into chalky-white, lightweight 'tombstone' kernels but stay inside the floret. Claviceps purpurea (ergot) instead replaces individual kernels with a hard, protruding body: first a sticky, sweet yellowish 'honeydew' drop oozes from the floret, then it hardens into a dark purple-black, curved horn (sclerotium) that sticks out well beyond the glumes, far larger than a normal grain. Key tell: pink/orange fuzz and shrivelled pale grains = Fusarium; a black horn-shaped lump replacing a grain = ergot.

• pink snow mould