Unfortunately, the magnificent delphinium (Latin: delphinium) is very susceptible to various diseases, which repeatedly spoils the joy of the beautiful flowers. We present the most common types of damage here.
Although delphinium is used as a medicinal plant, it can also be affected by diseases itself
powdery mildew
In hot, dry weather, powdery mildew feels very comfortable on leaves, shoots and flowers. The fungal attack is indicated by a white coating reminiscent of flour.
spider mites
Silvery-bright speckles appear on the leaves at first; later the leaves turn yellow and the plants appear to be covered with a fine web, which is particularly evident on the undersides of the leaves. Barely visible mites suck out the plant cells, with the arachnids appearing mainly in dry air and warm weather. As a precaution, you should definitely avoid over-fertilizing with nitrogen.
miner flies
An infestation with leaf miners is indicated by conspicuously meandering, silvery tunnels and white dots on the leaves. The leaf miner, which sucks plant sap, lays its eggs in the leaf tissue; the larvae eat through the leaves and pupate there. Chemical control is usually not necessary, just remove affected leaves.
rust fungi
If the upper sides of the leaves turn yellow to rust-brown in spots from early summer, then there is probably a rust fungus infestation. The initially small spots later turn into brownish, reddish or orange-colored pustules. Rust fungi occur primarily in damp weather when it has previously rained continuously for a long time. For prevention, spray several times with fungicides or an infusion of yarrow.
root rot
Although the delphinium has to be watered regularly, especially in dry periods, it is better to prevent waterlogging. This inevitably leads to root rot and thus to the death of the plant. Root rot is caused by various fungi that thrive in wet and compacted soil. The first signs are usually shown by the tips of the shoots turning brown.
tips and tricks
However, symptoms of damage are not always immediately due to diseases or pest infestation. They also result from wrong or deficient nutrition as well as from mistakes in the choice of location.