Gooseberries can be affected by a fungal disease, although the triggers are manageable. Usually two species appear on the trees that are reminiscent of powdery mildew infestation. Since combating it often requires effort, you should prevent fungal infestation.
How do I recognize and combat fungal infestation on gooseberries?
Gooseberries can be affected by two types of fungi: American gooseberry mildew and European gooseberry mildew. You can prevent it with regular cutting, balanced fertilization and good plant management. In acute infestations, plant protection products such as wetting sulfur, potassium hydrogen carbonate or lecithin help.
American gooseberry mildew
Sphaerotheca mors-uvae belongs to the order of powdery mildew fungi and is widespread among susceptible gooseberry varieties. However, the species introduced into Germany has a difficult time with modern breeding. Infected berries are not suitable for consumption.
malicious image
Not only leaves, but also shoot tips and fruits are attacked by this type of fungus. First, a fine white fungal mycelium appears on the tips of the shoots, which later spreads to the leaves and gooseberries. As the braid thickens, it takes on a brown color and resembles 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.
Impact:
- Loss in fruit yield as it cannot fully ripen
- Weakening of plant he alth due to high energy consumption for alternative shoots
- Impairment of the development of flower systems
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 cuttings with household waste. Remove branches that grow low on the trunk. If the fruit ripens too close to the ground, the susceptibility to fungal infection is increased. Make sure the crown is balanced. This should neither appear too dense nor be too exposed. Also avoid one-sided fertilization with nitrogen.
Combat
If the disease occurs more frequently on a plant, you can spray a product containing net sulfur (€6.00 on Amazon). Apply the preparation before the new leaves emerge. Please note that the varieties react differently to the active ingredient.
European gooseberry powdery mildew
Microsphaera grossulariae is another type of mildew. It is considered harmless compared to American mildew disease. This fungal disease occurs from July to August when the harvest has already been completed. The typical damage pattern includes roundish spots on the leaves that appear grayish and dry in the middle and have dark edges. A fungal mycelium with a whitish color develops on the underside of the leaf, from which yellow fruiting bodies later emerge. As the spores mature, they turn black, while the fungal network on the leaves appears hardened and brown.
Tip
This species rarely attacks shoots and does not infect fruit.
Does combat make sense?
Usually it is not necessary to fight the disease directly. If the plant is severely affected, you can use plant protection products with potassium hydrogen carbonate. Lecithin, which is found in milk, also proves effective against this mildew. Products containing sulfur that are used to treat gall mites have a side effect that inhibits mildew fungi.
