Barberries are naturally a defensive plant genus. They use sharp thorns and poisonous ingredients to keep predators away from the flowers. Cunning pests can take down the bushes themselves if necessary. In the fight against two diseases, barberries need the support of the gardener. This guide explains the exact connections.
What diseases commonly occur in barberries and how to combat them?
The most common diseases of barberries are grain rust and powdery mildew. Grain rust can be recognized by yellow-red pustules and can be combated with pruning and biological preparations. Powdery mildew appears as a floury-white coating and can be treated with a milk-water mixture.
Fighting grain rust effectively – this is how it works without chemicals
At the beginning of the 20th century, barberries were almost extinct because they act as an intermediate host for the dreaded grain rust (Puccinia graminis). This is a fungal infection that causes major damage to grain cultivation. The spores use barberry species as a location for one of their five development cycles on the way to the primary host, the grain. The following overview lists symptoms and control methods:
- Yellow-red pustules on the tops of the leaves, large, light yellow spots as spore deposits on the undersides of the leaves
- As it progresses: black discoloration and shedding
- Immediate measure: Cut back all infected plant parts
- Biological control: preparations with net sulfur or copper, such as net sulfurite (€6.00 at Amazon) or Atempo copper fungus-free from Neudorff
If grain rust is already rampant in your area, we recommend strengthening your barberries as a preventive measure with field horsetail broth, which you can make yourself or purchase from specialist retailers.
Fight barberry mildew - with this home remedy you can do it
If a mealy-white coating covers the lush green leaves of a barberry, powdery mildew has struck. The widespread fungal infection cannot be stopped by the toxic alkaloids from spreading to foliage, shoots and even the thorns. As a fair-weather fungus, the obvious symptoms usually become apparent during the summer. The appropriate control agent is already in your refrigerator. This is how it works:
- Cut off severely affected plant parts and dispose of them in household waste
- Add 125 ml of fresh milk to 1 liter of water, stir and pour into a spray bottle
- At intervals of 3 days, spray the infected barberry repeatedly with milk-water until dripping wet
It is important that you use fresh milk and not long-life milk. The lecithins it contains kill the fungal spores.
Tip
Balanced care is the best prevention against diseases on barberries. The organic nutrient supply plays an important role. Please avoid nitrogen-based fertilization with blue grain or similar mineral products. Starting fertilization with compost and horn shavings in March/April completely covers the nutrient requirements of all barberry species.
