Late Blight: Fungus In The Fast Lane

Unlike Alternaria as discussed last week, late blight (Phytophthora infestans) does not creep into a tomato crop.

- Bill Kerr

Instead, it can destroy the entire crop within hours. You therefore need to know the conditions that favour this disease to catch it in time.

Each spot can produce hundreds of thousands of spores within 48 hours. If the conditions are right for the disease and you forget to inspect the crop for two or three days, you could face huge losses.

Fortunately, with today’s systemic products, control is far easier and more effective than before. I knew a farmer in the Lowveld who started spraying his tomato crop as soon as conditions favoured late blight. He ran out of fungicide, went to town to buy more, and returned a few hours later to continue spraying.