Like many plants, grapevines are susceptible to certain diseases and pests. In this guide, we show you what these are and how you can treat and prevent them.
– Powdery mildew on grapevines – Downy mildew on grapevines – Gray mold: infestation on grapevines – Grape phylloxera: infestation on grapevines
Powdery mildew on grapevines
One of the diseases Grapevine most frequently added, is the Powdery mildew (Oidium tuckeri). Powdery mildew is a Fungal disease, which can cause significant damage to the infested plant.
How to recognize powdery mildew on grapevines?
Powdery mildew occurs in clusters from the end of May, sometimes not until the beginning of June. On the leaves and new shoots of the grapevine a white-grey coating is formed. It reminds a little of Cobweb.
At the beginning it is difficult to recognize, towards the end of the summer towards the fall the fungal coating turns gray. This coating inhibits the growth of shoots and leaves.
From the end of May onwards, infestation with powdery mildew is most likely to occur. The coating on the plants resembles cobwebs.
What helps against powdery mildew?
The best thing is to prevent powdery mildew. There are varieties of grapevine that are resistant to fungal diseases. These are for example the fungus-resistant varieties "Ester" or "Nero".
You should also always break out foliage, especially where it grows too densely. This is how the grapevine dries out faster in humid conditions. diseases can not spread so quickly.
Is there an infestation of powdery mildew If the fungus is present on the underside of the leaves, it is best to treat the leaves with Net sulfur.
Downy mildew on grapevines
The downy mildew will also Leatherberry or leaf drop disease called. As with the true variety, the causal agent is a fungus.
How to recognize downy mildew on vines?
Characteristic of this disease in the early stages are yellowish spots on the leaves. These discolor later into brown and appear slightly oily. a whitish fungal turf is formed on the underside of the leaves.
If the infestation is already more advanced, the spots and the fungal lawn can also be found on the shoot tips, tendrils, inflorescences and the young berries. If grapes are already formed, they become wizened, brown and fall off.
Due to their leathery appearance they are called leather berries. This has given the disease its second name.
The infected berries and foliage should be removed, otherwise the fungus will overwinter on the ground and start again next year.
You can recognize downy mildew first on the leaves of the grapevine. They turn yellowish.
What helps against downy mildew?
Preventive search mildew resistant vines from. These are for example "Muscat bleu" with its blue grapes. Also the yellow varieties "Lilla" and "Palatina" are resistant to the disease.
In addition you also cut here older foliage out. So the vines are better ventilated. The faster the leaves dry off after a downpour, the lower the risk of powdery mildew infestation.