The classic, trumpet-shaped flowers of brugmansia make it a favorite of gardeners everywhere, but brugmansia diseases can stop this plant’s display short. Because brugmansia is a close relative of tomatoes, issues with brugmansia are similar to those of its popular cousin. Treating sick brugmansia plants starts with the correct identification of the pathogen involved.
Understanding the pathogen is the best way to get started with diseased brugmansia care. Although this list is far from exhaustive, being able to recognize these common brugmansia diseases will help you make the right care decisions for your plant:
Bacterial Leaf Spot – Caused by the bacteria Xanthomonas campestris pv. hederae, bacterial leaf spot is encouraged by high humidity. It appears as a series of small, brown spots surrounded by a yellow halo and can spread rapidly. When it appears, thin your plants to increase air circulation, clean up any fallen plant debris and remove all affected leaves to slow or stop the infection.
Downy Mildew – This common fungal disease is caused by a number of fungal pathogens, but it always appears similarly. When you notice irregular yellow spots on the tops of your plant’s leaves and a webby or cottony growth on the underside, you’ve got downy mildew. You can treat it easily with neem oil, applied to both sides of the leaves at 7- to 14-day intervals for several weeks.
Powdery Mildew – Powdery mildew is very similar to downy mildew and is treated in the same way. Instead of the fungal mass being on the underside of the leaf though, a powdery, mealy substance appears on the top of the leaf. Both diseases can be deadly if left untreated and plants may benefit from a reduction in the humidity level.
Root Rot – Common soil fungi, like Pythium, are responsible for destroying the roots of brugmansia when the soil has remained waterlogged for an extended period. Sick plants will wilt readily and may appear less vigorous, but you won’t know for certain you’ve got root rot unless you dig your plant up and check the roots. Black, brown, or soft roots, or those whose sheaths slide off readily, are already dead or dying. You can sometimes save these plants by repotting them in dry soil with excellent drainage and watering them well. Never leave a plant in standing water, as this only encourages root rot.
Verticillium Wilt – A devastating and all-too-common problem, verticillium wilt is the result of a pathogenic fungus that enters the affected brugmansia’s transport tissues through the root system and rapidly multiplies. Plants typically will die in sections, with yellow leaves appearing all along one stem early in the disease. As it spreads, more of the plant wilts and drops. There is no cure for verticillium wilt, but planting future brugmansia in sterile soil can help to prevent it from taking hold.
Viruses – Tobacco mosaic and tomato spotted wilt viruses are the most common viruses among brugmansia. Tobacco mosaic causes a distinctive mosaic pattern of yellow and green areas on the leaf, along with deformed fruits and flowers. Tomato spotted wilt stunts plant growth and causes brown to black streaking on stems, as well as leaf deformity and yellow veins. Unfortunately, viruses are for life in plants. All you can do is destroy the infected brugmansia to prevent from spreading the disease to nearby plants.
Slugs, snails, aphids, spider mites and mealybugs are just a few of the insect pests that may attack angel trumpets. Brugmansia Growers International recommends using a miticide to remove spider mites and an insecticide containing pyrethrum to remove aphids and mealybugs. Releasing predatory insects such as lace wings or lady beetles may also help organically reduce pest populations. Slugs and snails can be removed and destroyed by hand in the evening when they are most active.
The flowers, leaves and seeds of all angel trumpets contain the toxic alkaloids atropine, scopolamine and hyoscyamine. Ingesting or smoking the plant may cause poisoning symptoms such as hallucinations, muscle weakness, increased pulse and blood pressure, dilated pupils and dry mouth. In some cases paralysis may occur, according to the North Carolina State University Extension Service. Floridata warns that using the plant for its narcotic effects may result in death. Angel trumpet may not be suitable for homes with children or pets.
Do the names Datura and Brugmansia represent the same plant? No – but these two genera are in the same plant family (Solanaceae), and up until 1973, all Brugmansia species were included in the Datura genus. The common name “angel’s trumpet” is often used interchangeably for both genera. In addition, both Datura and Brugmansia are notorious for their poisonous qualities. So there’s plenty of room for confusion.
Perennials expert Allan Armitage provides three particularly useful criteria for separating the two genera. In general, Brugmansia flowers will be pendulous, as compared with the upright orientation of Datura flowers. Brugmansia flowers will tend towards white, yellow or peach Datura flowers are usually white, or white and purple. Finally, Brugmansia fruit are smooth and not dehiscent (do not split open). Datura fruit are prickly and dehiscent.
Both genera produce beautiful, fragrant flowers. However, the fragrance can actually create problems by drawing people a bit to close for too long. It is known, for example, that sleeping near open Datura flowers can result in headache, nausea, dizziness, and weakness. Similarly, in a recent article in the magazine Homestead, Kathy Howard of Cornell University related an incident in which a couple picked up a Brugmansia and brought it home inside their vehicle. The half-hour drive home was long enough for the “toxic fumes” of the sweet-smelling flowers to make the gardeners “really sick”. Maybe transporting the Brugmansia in the trunk, or at least leaving the windows open, would have been a safer approach.
Datura and Brugmansia have wonderful ornamental qualities, but we should handle these plants with care and use them in locations where people and pets won’t get too close.
Brugmansia sanquinea, San Francisco Botanical Garden. Photo by Mark Weathington, NCSU
Datura wrightii, also known as jimsonweed, at the Bandelier National Monument in New Mexico. Photo by Tim Alderton, NCSU
Just a slight imbalance in soil, light conditions, temperature and watering can make a plant sick. So can pests and fungus. Caring for sick plants is a process of diagnosing symptoms and implementing corrective measures. There are standard procedures to follow regardless of whether the sick patient is a houseplant or an outdoor plant. Once you determine the root of the problem, you can take steps to alleviate the cause and nurse your plant back to health.
Look at the soil and base leaves. Are there bits of white moss growing on top of the soil or are the base leaves falling off? This could mean the plant is being over watered. If the roots of the dying houseplant are water logged, transplant into another pot and cut back on watering.
Are the leaves of the plant limp or yellow or brown in color? This happens when the plant is not receiving enough water and nutrients. Placing a water meter in the soil can help you better monitor when a houseplant needs water. Start the plant on a fertilizing schedule so it begins receiving the nutrients it is missing.
Some plants require more alkaline or acidic soil. Use a pH tester and be sure your plant's soil is appropriate for good health. Use soil additives or different potting mixes to bring the pH to the right level.
Examine the plant’s structure. Is its growth thin and weak with wiry offshoots growing upward? This is a sign that the plant is not receiving enough sunlight. If the sick plant is outdoors in an area that gets mostly shade during the day, you may need to transplant it to a sunnier spot. If it is a houseplant, either move the plant to a sunny window or relocate under florescent lights that are on a good portion of the day or night.
If there are burn spots on the leaves, the plant is likely receiving too much sun or is too close to a window where the sun is reflecting too much heat off the glass.
Inspect the leaves of the unhealthy plant carefully. If leaves are damaged, turning brown, or curling up, this could be caused by pests or a pest-caused diseases. Caterpillars, spittle bugs, greenflies, mites, grubs, whiteflies, spider mites and other pests and insects leave signs of their presence, such as tiny holes or half eaten leaves. Look on top and under leaves for signs of pest infestation. If you spot any, apply a pesticide.
Using a magnifying glass, look for signs of fungal disease. This could show up as black or brown spots on leaves, white or gray powdery mildew on leaves and stems, small spots of white foam on leaves, or spider-like webbing on various parts of the plant. Treat with the appropriate fungicide.
Review the care instruction card that came with your plant to make sure you are following the recommended guidelines for watering, light conditions and fertilizer.
Remove unhealthy growth from your plant immediately so new leaves can grow.
Exposure to these Brugmansia species is highly poisonous as it may cause the anticholinergic syndrome in the central nervous system.
This plant comprises of high amounts of tropane alkaloids, the leaves have 0.4% of hyoscine, and the flowers have around 0.83% hyoscine.
The other toxic plants containing similar amounts of tropane alkaloids include Hyoscyamus and Datura stramonium (jimsonweed).
These alkaloids possess hallucinogenic elements, leading to fatalities and abuse.
Human intoxications typically occur due to handling the plant without wearing protective gear or consuming tea-infused with the flowers and fresh leaves.