Common thorn apple
Datura stramonium
Appearance
The leaves of the common datura are dark green on top, long-stalked, ovate, pointed, lobed and sometimes very large (20 cm in diameter). The species is characterized by a great variability in appearance. Depending on nutrient, water, and competition conditions, growth height at seed maturity can vary from a few centimeters to more than 150 cm.
The trumpet flowers stand upright in the branch forks. From them a characteristic densely spiny, walnut-sized capsule is formed, in which deep brown to black seeds are found. The ripening of the fruit capsules extends into September and October.
Distribution
Common Datura has become an important weed only in recent decades. An increased occurrence was first observed in the 1990s. The "hotspots" of datura are currently located in the warm lowlands of northern Burgenland and eastern Lower Austria. In southeastern Styria and in Upper Austria occurrences could be observed in recent years. For Carinthia there are only isolated records in fields. Further in the west it is (still) too cold for the datura, here it occurs, if at all, on ruderal sites.
Outside of agricultural areas, the species mainly colonizes nitrogen-rich ruderal meadows (garbage dumps, compost heaps, urban fallow land, abandoned gardens).
Spread and transmission
- Natural dispersal: Seeds are dispersed from the capsules when they burst and also by wind movements up to a distance of 1 to 3 metres from the mother plant.
- Anthropogenic dispersal: Seeds are spread over long distances with the help of agricultural equipment and harvesting machines.
Economic importance
As a warm sprout, the common datura emerges relatively late and can therefore be found in fields, especially in summer annual crops such as corn, soybean, potato, sunflower, millet, but also in field vegetables.
Especially in field crops with a low growth height, the common datura can develop an enormous competitive power and cause high yield and quality losses. Much more problematic is the fact that the entire plant is highly toxic, as it contains organic compounds(tropane alkaloids). Contamination also occurs when seeds come into contact with plant parts and plant juices of the (green) datura during harvesting. Relatively small amounts of these alkaloids, when ingested with food, can cause poisoning (sensory deprivation, nausea, drowsiness, respiratory paralysis) in humans and animals.
Prevention and control
Direct measures
- Mechanical weed control with harrow and hoe. The harrow only has an effect on small individuals. Coulter hoes also capture larger plants. Specimens in the row are often poorly controlled.
- Selection and use of effective herbicides in the crops(list of plant protection products authorised in Austria)
Checking the crops
- Check before the crop closes, but at the latest before harvest: individuals must be removed before seed formation.
- Removal of individual plants or smaller populations is best done by pulling out or digging up. Disposal: Do not leave plants at the edge of the field, but put them in rubbish bags and dispose of them with the residual waste. Larger quantities can be sent to professional composting or biogas plants.
Last updated: 07.11.2023
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