CHOW TO BEAT POTATO BLIGHT

Anton Rosenfeld from Garden Organic shares toolkit for tackling blight his troubleshooting

- Anton Rosenfeld

Blight is a virulent fungal disease that can wipe out potato crops or tomatoes very quickly. It can strike from any time after June, and the incidence increases through the growing season.

Most of us who have grown potatoes have seen it at some stage – and organic methods are a good way to manage this disease. But organic management does not mean sitting back and letting the disease run riot. It means taking a range of preventative measures to reduce its chances of breaking out.

WHAT IS POTATO BLIGHT?

First, you need to recognise blight and how it behaves. As it’s airborne, it will infect the leaves first, and you may notice its distinct brown to grey lesions. These are about the size of a penny, and appear close to the edges of leaves. (Don’t confuse this with smaller brown dots which are more likely to be a nutrient deficiency such as potassium or magnesium.)

The disease is far more likely to take hold if the weather is damp and still, as this is ideal for allowing the fungal spores to settle and germinate on the surface of the leaf. In tomatoes, it can be spread by water splash, and in serious infections be seen on the fruit. 

HOW TO DEAL WITH A BLIGHT INFECTION

If you notice just a few infected leaves, remove them and dispose of them in your green waste bin where they will be composted at high temperatures. If dry conditions follow, you may be lucky, and the crop can be salvaged.

If you are unfortunate, and the disease becomes widespread throughout the leaves, it might be time to cut your losses.