By Colby Tibbet, Cal Ag Today reporter
Palmer amaranth, aka Amaranthus palmeri S. watson or carelessweed, is an annual herb of the pigweed species that is native to California where it thrives and poses a serious threat to farming.
Lynn Sosnoskie, a project scientist in the UC Davis Department of Plant Sciences who focuses on weed ecology and biology, says Palmer amaranth, spotted on the edge of fields in California, is remarkably aggressive both in growth rate and spread amidst field crops. It develops a lot of wind-blown seeds that spread rapidly.”
“I would suggest that growers in the state of California be particularly diligent about this plant,” said Sosnoskie. “It is a desert annual and is particularly well-adapted to dry environments where it can out-compete, create root growth and achieve stability well. And the recent drought has only escalated the problem.”
“Preventive measures are absolutely essential before this plant becomes established,” continued Sosnoskie. “We found out the hard way in the Southeastern U.S. that Palmer amaranth produces an exceptional number of seeds; if even one plant is missed by applications or escapes regular herbicide applications, that plant can essentially repopulate an entire field.”
“So its absolutely essential that growers here and everywhere become familiar with the weed and remove all plants quickly from a field before it hits reproductive maturity and forms seed,” she said.
Sosnoskie added that some cotton fields in the south have suffered up to 50 percent yield losses and worse. “Some growers have actually abandoned their fields and haven’t harvested their cotton for those years,” said Sosnoskie.
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