Parthenium hysterophorus (Famine Weed) poses threat
- Nicole Schwandt
- 3 days ago
- 3 min read
Parthenium hysterophorus, commonly known as famine weed, is one of the most aggressive and destructive invasive plants currently spreading across parts of Africa. Native to the Americas, this daisy-like plant may seem insignificant at first glance, but it poses serious threats to agriculture, human health, biodiversity and public infrastructure. It is also known by other names such as Demoina Bossie, Congress Grass, or Santa Maria.
Famine weed has recently been detected in Windhoek, according to NBC Digital News. Although still relatively new in Namibia, its spread in other countries has followed a rapid and devastating trajectory. It invades disturbed land, roadsides, grazing areas, croplands and watercourses. The plant spreads easily via wind, water, animals, vehicles, shoes and clothing. Each plant can produce up to 25,000 seeds, and these seeds can remain viable in the soil for more than 50 years.
Early detection and eradication is absolutely critical.
The presence of famine weed in Namibia is a serious concern for farmers and land users. It suppresses the growth of other plants through a process called allelopathy, where it releases chemicals that inhibit the germination and growth of nearby vegetation. It thrives in degraded soils and overgrazed areas, which are common in dryland farming systems. For livestock farmers, the risks are particularly high: animals that consume famine weed produce tainted meat and milk, rendering these products unfit for sale or consumption.
In addition to agricultural threats, famine weed is hazardous to human health. It causes skin rashes, respiratory illnesses, and allergic asthma. Continued exposure – especially for farmworkers and those living in infested areas – can lead to chronic health issues. The plant also poses a significant threat to biodiversity. It outcompetes indigenous vegetation, reduces available grazing for wildlife and invades conservation areas and game reserves. This may worsen existing problems such as bush encroachment, fire intensity and soil erosion.
There are also public health implications. Recent research has indicated that famine weed may increase mosquito survival rates, thus elevating the risk of malaria transmission in affected regions. Its impact is wide-ranging and affects the poorest and most vulnerable communities the hardest, as their livelihoods depend heavily on healthy land and livestock.
Famine weed can be identified by its pale green, deeply lobed and hairy leaves, and small white flowers clustered at the tips. It typically grows 1.5 to 2 metres tall and is most visible between the months of September and May. Alarmingly, contact with the plant – even via airborne particles – can cause skin and respiratory irritation.
To prevent the spread of famine weed, immediate action is required. The most important step is to remove plants before they flower or set seed. All flower heads and seed material should be burned, not composted or discarded into the environment. Farmers and landowners are urged to regularly monitor vulnerable areas such as kraals, roadsides and animal congregation points. Equipment, tools, shoes, and vehicle tyres should be cleaned after working in or passing through infested areas.
Suspected sightings or infestations should be reported to [email protected], and more information is available at www.cactusclean-up.com. Long-term solutions include the introduction of biological control methods, such as natural predators and insects used in other countries. However, these options are not yet widely available in Namibia and prevention remains the most cost-effective strategy.
In the meantime, good veld management is essential to suppress the spread of famine weed. This includes avoiding overgrazing, maintaining healthy ground cover, and limiting soil disturbance. Every plant that goes to seed now adds to the burden future generations will face. By acting early, Namibia still has a chance to stop famine weed before it becomes an uncontrollable crisis.
- Flyer
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