Czech gardeners urged to monitor tomatoes for late blight after heavy rains

Heavy summer rains in the Czech Republic have created ideal conditions for the spread of Phytophthora infestans, the pathogen that causes late blight on tomatoes. Experts advise growers to inspect the lower leaves of tomato plants the morning after rain, again after 48 hours, and then every two to three days. Early signs include gray‑green spots on leaf edges that turn brown and a white‑gray fuzzy coating.

Preventive measures focus on proper watering—apply water to the soil, not the foliage—and using potassium‑rich fertilisers. Home‑grown solutions such as wood‑ash tea, banana‑peel extracts and compost leachate are recommended. Removing lower leaves, supporting heavy fruiting branches with stakes or trellises, and avoiding leaf wetness during irrigation help reduce infection risk. These practices are especially important in August, when high temperatures and humidity further promote disease development.