The spread of invasive plant species often goes unnoticed until significant damage is done. In Arizona, a noxious weed called stinknet (Oncosiphon piluliferum ) is rapidly expanding, threatening native wildflowers, increasing fire hazards, and even posing health risks to humans and animals.
What is Stinknet?
Stinknet is an annual weed that thrives during cooler months, aggressively outcompeting native plant life. It’s currently spreading across Maricopa, Pinal, and Pima counties in Arizona, as well as in parts of Nevada, California, Mexico, and Australia. Its adaptability allows it to flourish in a wide range of environments, from urban cracks to undisturbed desert soils.
The weed’s invasive nature is alarming because once it establishes itself, eradication becomes extremely difficult. Scientists believe it arrived in Arizona via contaminated soil or vehicles from California, where it was first identified in 1981. The delay between introduction and recognition is a common issue with invasive species—by the time they’re noticed, populations are often too large to control easily.
Identifying Stinknet: Appearance and Smell
Stinknet is easily identifiable by its bright golden-yellow flowers and dark green, carrot-like leaves. While it may superficially resemble wildflowers, its impact is far from benign. The plant aggressively consumes resources, choking out native vegetation. It produces thousands of seeds that can remain viable in the soil for up to five years, ensuring continued spread.
The weed’s most distinctive feature is its overpowering odor. Described as pungent and similar to turpentine, the smell becomes particularly intense when the leaves are crushed. Brian Shomo, director of Natural Resources with the Riverside County Habitat Conservation Agency, notes the smell is so strong “it can give you a headache.”
Why Stinknet is Dangerous
Beyond the unpleasant odor, stinknet poses significant risks:
- Fire Hazard: The plant is highly flammable and can fuel wildfires.
- Health Concerns: Contact with stinknet can cause skin rashes and respiratory problems. Smoke from burning stinknet also carries these risks.
- Ecological Damage: It destroys native wildflowers, disrupting the ecosystem and reducing biodiversity.
Managing Stinknet: Prevention and Removal
Controlling the spread of stinknet requires vigilance and action:
- Reporting: Photograph any sightings and report them to stinknet.org. The website also maintains a map of reported locations.
- Cleaning: Thoroughly clean footwear and clothing after hiking in affected areas to prevent seed dispersal. Keep pets away from stinknet.
- Removal: Carefully dig up weeds from the roots while wearing protective clothing (gloves, long sleeves). Bag plant material securely and dispose of it properly.
- Herbicides: Glyphosate and pre-emergent herbicides can be effective, but always follow label instructions and wear proper protection.
The rapid spread of stinknet highlights the ongoing threat of invasive species to ecosystems and public health. Early detection, reporting, and responsible removal are crucial to mitigating its impact.
