Potato blight is still one of the most devastating potato diseases in the UK. It is a fungus (Phytopthora infestans) that has the potential completely to destroy crops. It first infects the leaves, then the infection spreads to the tubers where they rot. Potatoes grown on a garden scale are just as susceptible to the disease as commercial crops. https://www.gardenorganic.org.uk/can-mesh-netting-reduce-potato-blight