As long as it feels comfortable in its location and is cared for according to its needs, the trumpet tree (Catalpa bignonioides) is only slightly susceptible to pests and diseases.
Wilted leaves can be an indication of the insidious Verticillium wilt
It depends on the right location
Prevention is always better than cure, which is why you can prevent the most common diseases of the trumpet tree with simple measures. Various fungal and viral diseases, but also various pests (such as aphids) primarily attack already weakened specimens, while strong and healthy trees can usually defend themselves very well against such pathogens. Therefore, choose a sunny, sheltered location with sufficient space and loose, permeable, moist and nutrient-rich soil.
Typical pests of the trumpet tree
Aphids in particular like to settle on the large, succulent leaves of the trumpet tree. You often notice an infestation because the leaves are sticky due to the sweet excretions - and therefore more ants find themselves there. These feed on the so-called honeydew and can cause further damage to the tree. Fortunately, aphids can be combated with fairly simple methods. Incidentally, the little animals appear more frequently in the spring. In addition to aphids, various types of caterpillars like to nibble on the leaves - only regular collection helps here, especially in the early morning hours.
fungal diseases
In particular, trumpet trees that are incorrectly cared for or in the wrong location are prone to certain fungal diseases. However, an infection is not always behind it when the leaves of the plants turn yellow - sometimes the tree simply suffers from excessive drought or - this must be clarified carefully - from waterlogging.
gray mold rot
If mainly young, soft shoots dry up and die for no apparent reason, this is often due to gray mold. This disease, caused by the Botrytis mold, is often noticeable when it is in an advanced stage by a greyish to blackish fungal growth. The parasite appears mainly in humid summers, but can be easily combated with fungicides.
Verticillium wilt
In contrast, an infection with the Verticillium fungus that lives in the soil is much more dangerous for the trumpet tree. This pathogen gets directly into the tree’s pathways via the roots and blocks them. As a result, individual leaves and shoots die first, and later the entire tree. There is no effective antidote, you can only try to radically prune the infested trumpet tree - far into the healthy wood - and then transplant it to another location.
tips
Above all, do not plant the trumpet tree in a location where contagious diseases such as Verticillium wilt have already occurred.