Esca

What you see

Leaves develop yellow or red blotches between the veins that dry to brown, leaving a narrow green strip along the veins and the margin - the tiger-stripe pattern. In the sudden form, an entire vine wilts and dies within days in midsummer. Cut the trunk across and the wood is dark, spongy and streaked.

Conditions

Infection enters through large pruning wounds, usually years before symptoms appear. Hot dry summers trigger the collapse in vines already colonised.

Treatment

There is no cure. Remove dead vines. Some growers practise trunk surgery, cutting away the decayed heartwood, with mixed results. Prune to leave small wounds only.

Prevention

Prune late, in dry weather, leaving the smallest wounds you can, and seal large cuts. Do not leave pruning debris in the vineyard. Buy clean nursery material.

Months: June, July, August

Plants

Grape

Remedies

Not recorded — the field is blank rather than guessed.

The thing people get wrong

Symptoms show years after infection, which makes cause and effect almost invisible - the vine that dies this August was infected by a big pruning cut five winters ago. That is why the only real control is a pruning habit rather than a treatment: small wounds, late cuts, dry weather. Esca is now the most serious vineyard disease in Europe and there is nothing to spray at it.