The ball trumpet tree (Catalpa bignonioides) is not only a conspicuous appearance, but also quite useful: Its leaves in particular contain a slightly fragrant toxin that reliably keeps mosquitoes away. In contrast to its large relative, the trumpet tree, this variant flowers only very rarely and when it does, then only at an advanced age. The tree, which is actually quite easy to care for, is rarely attacked by pests, but is quite susceptible to certain diseases.
Stains and wilted leaves are often a sign of disease
Only prevention helps against Verticillium wilt
Unfortunately, the ball trumpet tree is quite susceptible to Verticillium wilt, also known as wilt disease. This is caused by fungi living in the soil, which get through the roots into the ducts of the above-ground parts of the plant and block them. As a result, the plant is no longer sufficiently supplied with water and nutrients, so that individual shoots wither and die and individual leaves turn yellow and/or curl. There is no effective antidote to this usually fatal disease, you can only rely on prevention:
- Never plant a susceptible deciduous tree in an area where Verticillium wilt has previously occurred.
- Plant the ball trumpet tree in well-aerated, nutrient-rich soil.
- Water and fertilize it regularly or as needed.
- When cutting, only use sharp and clean tools.
- Employ a herbal tonic.
What to do if there are signs of wilt disease?
If you notice the first signs of Verticillium wilt on your trumpet tree, you can still try to save it:
- Thoroughly cut back affected parts of the plant down to the healthy wood.
- Dig up the tree and carefully rinse off the clinging soil.
- Remove diseased looking roots.
- Plant the tree in a healthy spot or in a container.
- Never dispose of cut plant parts in the compost.
- Treat the tree with a plant strengthener.
Powdery mildew - typical in hot summers
A powdery mildew infection is easy to recognize from the white-grey, mealy-looking fungus that covers the leaves and shoots of the affected tree. This disease often occurs in very hot summers, but is usually very treatable. To do this, you can spray the infested globe trumpet tree with a mixture of whole milk and water (in a ratio of 1:10) for several days in a row.
tips
Also the smut fungus - which fortunately occurs very rarely - usually has deadly consequences for the tree. The same precautionary and treatment measures apply as for wilt disease.