A weed strong enough to stop combines and resist many herbicides has been confirmed in South Dakota for the first time, raising concerns it could spread and cut deeply into crop production in the Upper Midwest one of the few areas it hadn’t yet invaded.
The threat from Palmer amaranth [Amaranthus palmeri] is so great that officials in North Dakota have named it the weed of the year, even though it has yet to be found in the state.
“If you think you find plants kill it!” North Dakota State University Extension Weed Specialist Rich Zollinger said. “Don’t even think. Just kill it.”
Even glyphosate, Monsanto’s mighty Roundup, is helpless against this stuff:
Weed scientists have performed tests on resistant Palmer pigweed. In this study, glyphosate was sprayed on resistant pigweed three times at 88 ounces per acre. The Palmer pigweed that received 264 ounces of glyphosate was still alive and healthy. The drought-plagued cotton plants were dwarfed by the glyphosate-resistant weed.
And, just our luck, it’s prolific:
The plants can grow as tall as 7 feet, each one producing as much as a million seeds. Its stems can grow as thick as baseball bats.
Which certainly explains how it can stop a combine.