Gooseberries can be affected by a fungal disease, although the triggers are manageable. Normally, two species occur on the trees, which are reminiscent of a powdery mildew infestation. Since combating it often involves a lot of effort, you should prevent fungal infestation.
Gooseberries affected by fungi should not be eaten
American gooseberry powdery mildew
Sphaerotheca mors-uvae belongs to the powdery mildew order and is widespread among susceptible gooseberry cultivars. However, the species introduced in Germany has a hard time with modern breeds. Affected berries are not suitable for consumption.
damage picture
Not only leaves, but also shoot tips and fruits are attacked by this type of fungus. First, a fine white mushroom mycelium appears on the tips of the shoots, which later spreads to leaves and gooseberries. As the weave thickens, it takes on a brown tint, reminiscent of a felt covering. The compression of the young shoots is clearly visible, as their growth is negatively affected. Instead, replacement shoots develop on them, making the entire shrub appear broom-like.
Effects:
- Losses in fruit yield because it cannot fully ripen
- Weakening of plant health due to high energy consumption for alternative shoots
- Impairment of the development of flowering plants
prevention
Regular pruning during the winter months is one of the most important measures to contain the fungal disease. Shorten all shoots by a third and dispose of the clippings in the household waste. Remove branches that grow low on the trunk. If the fruit ripens too close to the ground, the susceptibility to fungal attack is increased. Pay attention to a balanced crown. This should neither appear too dense nor be too thin. Also avoid one-sided fertilization with nitrogen.
combat
If the disease occurs more frequently on a plant, you can spray a product containing sulphur. Apply the preparation before the new leaves sprout. Note that the varieties react differently to the active ingredient.
European gooseberry powdery mildew
Microsphaera grossulariae is another powdery mildew species. It is considered harmless compared to the American powdery mildew disease. This fungal disease occurs from July to August, when the harvest has already taken place. The typical pattern of damage includes roundish spots on the leaves, which appear greyish and dry in the middle and have dark edges. A whitish mycelium develops on the underside of the leaf, from which yellow fruiting bodies later develop. As the spores mature, they turn black, while the mycelium on the leaves hardens and appears brown.
tips
This species rarely affects shoots and does not infect fruit.
Does fighting make sense?
Usually it is not necessary to fight the disease directly. If the plant is severely affected, you can use pesticides with potassium bicarbonate. Lecithin, which is found in milk, also proves effective against this powdery mildew. Products containing sulphur, which are used to treat gall mites, have the side effect of inhibiting powdery mildew fungi.