Local citizens are becoming increasingly concerned about the spread of poison hemlock, a noxious weed with toxic properties. The concern not only stems from its invasive nature, but the fact that it is one of the most toxic plants in the world. Poison hemlock is well known for accidental deaths of humans and other animals. The death of Socrates in 329 B.C. is perhaps the most well-known case involving the death of a human.
Poison hemlock has been spreading across Adair County for about the last 10 years and has reached a point that it can be easily found in most parts of the county. Its spread locally appears to be via right of ways and along creeks. While it’s currently more abundant locally, it’s been in other parts of Kentucky for much longer. Native to Europe, poison hemlock is an invasive weed that was introduced as an ornamental in the United States during the 1800s.
According to JD Green, UK Extension Weed Scientist, cattle, goats and horses are considered to be the most susceptible animals, but other animals can consume it. If ingested, poison symptoms appear within 30 minutes to two hours, depending on several factors including the animal species and quantity consumed.
Lethal doses for cattle range between 0.2 and 0.5 percent of the animal’s weight. Poison symptoms include nervousness, trembling, muscle weakness, loss of coordination, pupil dilation, coma and eventually death from respiratory failure. If ingested by a pregnant animal, it can cause fetal deformities.
Landowners having problems with Poison Hemlock may apply a herbicide containing 2,4-D during the vegetative rosette stage of growth for control (November or March). Read and follow label directions for application rates and safety. Mechanical removal is also effective. Bush hogging prior to bloom is also effective in preventing seed formation. A fully mature plant is capable of producing 35,000 – 40,000 new seeds
Assistance with controlling poison hemlock is available through the state of Kentucky in two forms. First, KRS 176.051 provides the following option for landowners abutting state highway right-of-ways with poison hemlock.
“Upon written request, the department shall give priority to and shall cooperate with any abutting property owner engaged in a program of eradication by eradicating the noxious weeds and invasive plants identified in subsection (1) of this section, or in administrative regulations promulgated pursuant to subsection (4) of this section, from abutting state right-of-ways. The department shall take steps to eradicate this grass and these weeds or thistles by the use of chemicals or any other means found to be effective by the department.”
Secondly, the Kentucky Department of Agriculture provides a limited amount of demonstrations in each county each year to provide spraying equipment for up to 20 acres per landowners with a maximum of 10 landowners per county. The application period is available during February each year at www.kyagr.com
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