Know your blight

Blight can be a big worry for gardeners, but don’t jump to conclusions if your spuds show symptoms

- Bob Flowerdew

MANY things threaten our crops, with harsh conditions and all sorts of pests resulting in poorer yields. We can protect our crops to some extent from both of these – but a third threat, disease, is harder to avoid, potentially more disastrous and often more difficult to diagnose.

In years when potato blight (which also affects tomatoes) is prevalent, we will all suffer sooner or later. And because blight can wipe out our crop, we rightly fear it. Blight is a fungus that spreads fastest in warm, humid conditions, much less when it’s drier.

Blight tends to commence in the south-west region in early summer and move north-eastwards over the following weeks. The blight infection causes dark spots and lesions, mostly on the leaves, then runs in streaks down the haulm (stems) to infect the tubers and spoil those as it kills the plants.