Brugmansia, also called angel trumpet, can take the form of a tall bush or a small tree, depending on how it is pruned. It is a common landscape plant both because of its bright, trumpet-shaped flowers, but also because it is not particularly susceptible to root diseases, which can decimate landscaping shrubs. However, there are some other brugmansia diseases that can get overlooked because these bushes are so hardy in other respects. The best way to keep your brugmansia happy and healthy is to know the signs and symptoms of brugmansia diseases so that you can avert problems before they become serious.
Brugmansia plants are prone to developing leaf spot infections. These can be caused by a bacteria or a fungus and tend to leave brown discolorations on the leaves. In addition, the edges of the leaves may be brown, black and dead, and if the leaves are young when affected, they will likely be distorted. You can control leaf spot by sterile pruning to remove affected leaves and disposing of them completely, rather than allowing them to simply fall to the ground. If this does not provide sufficient control, then treat the brugmansia with a pesticide that contains copper to kill the infection.
If you have started to notice webbing on your brugmansia around the stems of the leaves or in the crotches of branches, then you may have spider mites. These small, black or red mites are nearly impossible to see since they are about the size of a grain of pepper, but their webs can create aesthetic and health problems for plants.
Mealybugs are very difficult to control. If they get into your brugmansia, you will be hard-pressed to get rid of them even if you use pesticides. These bugs are small, oval and look furry, as if they had been dipped in flour. If you have mealybugs, coat the leaves of your brugmansia with neem oil to make them less appealing to the insects' palate. Cover the top and bottom of the leaves. Repeat the treatment after a rain or every few days until the infestation has completely disappeared.