Powdery Mildew Flag Shoots
A flag shoot infected with Powdery Mildew
Powdery Mildew is one of the most widespread fungal diseases of grapevines in the world. It is characterised by ash-grey to white powdery growth on green tissue of the vine. If uncontrolled it can cause serious crop losses and impair wine quality. One spore of Powdery Mildew can multiply to 50 million spores in just 3 weeks!
Dormant buds can be infected and survive over winter. When these buds shoot they are deformed and covered with the powdery mildew spores. These shoots need to be removed and destroyed. We have come across several shoots this year but hopefully it isn't widespread.
Sulphur and Copper are traditionally used to control mildews on the vineyard. We are trying to avoid these treatments by using compost teas which populate the vines with friendly bacteria and fungi.