Fungus in Brugmansia: Stem Rot/Stem Blight

Fungus in Brugmansia: Stem Rot/Stem Blight

Written by Delisa Harvey

Our brugmansia are growing and soon it will be fall and we will want to share cuttings.  Fusarium and Phomopsis are two of the most devastating fungal invaders of brugmansia.  There are other fungal disease that mimics the signs of Fusarium and Phomopsis such as Pythium Stem Rot.  The only way to have a sure diagnosis of the disease is a report from a lab with disease diagnosis.  The reports will contain information about how to treat the diseased brugmansia.

One way that hybridizers of brugmansia are trying to decrease the incidence of stem rot is to breed brugmansia for stem rot resistance.  Many hybridizers are now crossing brugmansia without using Brugmansia suaveolens, which has been proven to be the most likely type of brugmansia that will contract stem rot.  Unfortunately, Brugmansia suaveolens is the most perfumed of all the Brugmansia species and the crossing for disease resistance is eliminating or reducing the intoxicating smell of the suaveolens species.

It is interesting to note that tomatoes are also in the same family as brugmansia Solanaceae (sol-uh-NAY-see-ee) and contract many of the same disease.  Tomato farmers, even with disease fungal resistant strains of tomatoes, still use fungicides as a disease preventative.

In order to keep fungal disease in check it is important to routinely inspect our brugmansia plants.  The following photo (Exhibit A) is of a diagnosed case of the fungus Fusarium in species suaveolens by the University of Florida Plant Clinic at Gainesville.

Exhibit A

Exhibit B is of a diagnosed case of Pythium Stem Rot and is remarkably similar in looks to Fusarium.  Without proper diagnosis there is no for sure way to tell which fungal disease is present.  

Exhibit B

As we prepare to share our brugmansia with our friends it is important that we can recognize that a disease may be present so we don’t “pass it on”.

    There are other methods that should be used so as not to distribute disease by accident.

#1 boil your clippers for a few minutes after using and before cutting on the next brugmansia.  Just don’t forget that you have them on the stovetop.  I keep 2 pair so that I may alternate clippers.

#2 while preparing brugmansia cuttings for shipping keep different brugmansia in separate wrapping.

#3 don’t send cuttings of a plant that shows disease.

#4 when receiving new cuttings keep these cuttings separate from your healthy cuttings until you are sure they are not showing signs of disease.

Growing and sharing brugmansia is a fun hobby or job.  It is also a demanding gardening experience in that we must be diligent in looking for and noticing disease in our plants.  Choose a scheduled time to admire and inspect your plants for disease.  Inspection can take place while you are watering and fertilizing or taking a morning or late afternoon walk through the garden.  If you find a suspicious lesion you may contact your local extension office and inquire about sending your specimen to a lab or post a photo of the plant for other members to see. It is possible a member may be able to help you right here.