What is in this article?:
• Long-time North Carolina State weed scientist Alan York says there are good reasons to call Palmer pigweed ‘Super’.
• In general, regardless of what crop you are growing, if you see one or two pigweed in a field you are sure was sprayed properly with glyphosate and you intend to continue using the herbicide, carefully remove the plant from the field, losing as few seed as possible.
Palmer amaranth is a relatively new weed for the upper Southeast. It has been dubbed ‘Super Weed’ in both agricultural and mainstream publications.
Long-time North Carolina State weed scientist Alan York says there are good reasons to call Palmer pigweed ‘Super’.
1.) Heat and drought tolerance: Palmer amaranth is native to the Sonoran desert of the southwestern U.S. Cotton and a few other popular crops grown in the Southeast like hot weather — the Super Weed doesn’t just like hot weather, it thrives on it.
“North Carolina growers who have glyphosate-resistant Palmer amaranth have seen their cotton droop over in this record hot weather we’ve been having this summer. The Super Weed just keeps growing— smiling at you,” says York.
When daytime temperatures get higher than 90 degrees most crops grown in the Southeast start to feel bad and begin to shut down. The optimum temperature for photosynthesis in Palmer amaranth is 108 degrees F.
2.) Deep and diverse root system: Probably due to its native habitat, Palmer amaranth has a deep growing tap root. It also has a very extensive set of fine roots extending from the taproot. The combination allows Palmer amaranth to explore the soil better than target crops and allows the Super Weed to get moisture when crops can’t do it.
3.) High photosynthesis rate: Palmer amaranth fixes carbon better than any crop plant grown in the Southeast. Its photosynthesis rate is about twice the rate of soybean and cotton and as least as much or more than corn.