Milestone is a range and pasture herbicide, manufactured by Dow Chemical, and intended to manage noxious weeds. A little goes a long ways, and it is widely used here in the Bitterroot, especially in hayfields to produce a weed seed free outcome. Although praised by the EPA for its persistence (meaning it requires less applications than most other herbicides Because it lasts longer), that persistence can prove deadly when composted manure from horses fed hay containing the aminopyralid is applied to vegetable or perennial gardens.
This year my entire vegetable garden has been destroyed by using our composted horse manure. The more susceptible plant types, such as bush beans, tomatoes, peas and sunflower, begin to die almost immediately upon uptake. Top growth appears grossly contorted; leaves narrow, cup, and curl, and within days of its appearance, the plants succumb and die. This season I lost 20 tomato plants, all my bush beans, and all my sunflowers right away. The two dozen hot pepper plants are still alive, but reflecting narrowing, twisted top growth; in fact, on some plants the growing point of the plants disappears completely. There are a few plants such as corn which, because they are related to grasses, do not appear affected by the Milestone. The problem remains, who wants to take a chance eating the corn if it contains this deadly aminopyralid?
I cannot tell you how devastated I am, watching my entire garden perish. I am a lifelong gardener who coincidentally was trained in the plant sciences, and worked in the ornamental horticulture industry. Gardening is very important to me; I find the activity therapeutic, and it sustains and nurtures my soul. I feel as sickened to stand helplessly by and witness my garden dying, as my plants appear.
The hay we purchased last year, from a decent couple of ‘horse people’ on the west side of the valley, had been treated with Milestone three years previously. They failed to pass this information to us at the time of sale.
But as I have since learned from our local Agriculture Extension agents, and heard from Dow themselves, this deadly material can remain active in the soil for up to five years. And, as amazing as this might seem, as little as ten parts per BILLION can cause damage.
In my individual case, not only have I lost my large garden this year, the soil beds which I have worked steadily to improve for the past nine years are now essentially a toxic waste site. Thank you, Dow Chemical, for your gift which keeps on killing.
My advice to horse owners who are dependent on buying hay for winter feed: ask the seller if they apply, or have recently applied, Milestone or other persistent herbicides to their pastures. Although it is clear what damage this material wreaks upon plant life, there are really no authoritative studies or binding research to confirm or deny what pernicious effect passing this herbicide through horses or other livestock may produce. Subsequently, no one is willing to say what impact it might have upon humans who knowingly or inadvertently consume produce containing aminopyralids.
The nearest I got to an answer to this specific query was “it’s up to you, and whether you want to risk it.”
Ironically, I am experiencing a bumper crop of raspberries at the present time, raspberries fertilized by nearly two yards of the affected manure. Raspberries which I will not risk consuming, and which will go to waste. Next year’s canes are now contorted, twisted and curling. I hope that folks here in the valley who follow similar gardening practices as I do, but who were unaware of the consequences of this deadly herbicide, will learn from my mistake and not find themselves in a similar conundrum. And if you’re knocking down the thistles and knapweed in your pastures with Milestone so you can sell your hay, have the common decency to inform the buyer.
Rick Landry
Corvallis