The Amaranth family, laying claim to nearly 75 different species, is a force to be reckoned with. Palmer amaranth and waterhemp rank among the top 5 most troublesome weeds, according to a survey by the Weed Science Society of America.

Southeast growers are all too familiar with the challenges these weeds pose in their soybean and cotton crops, in particular. As small-seeded, annual plants, amaranth species grow quickly in open areas with full sun and undisturbed soils, producing from tens of thousands to hundreds of thousands of seeds per plant.

• Due to rapid growth, aggressive competition, prolific seed production and germination throughout the season, Palmer amaranth, also known as pigweed, can reduce crop production and even hinder harvesting efforts.
• Waterhemp can produce more than 1 million seeds per plant. Just a few untreated weeds in a field can lead to a major infestation. With a germination period that lasts several months, waterhemp can grow in a variety of climates, as evidenced by its presence in 40 states. Waterhemp is identified by a lack of hair on its stems and leaves that give the weed a bright, glossy appearance.

The most effective control can be obtained when post-emergence herbicides like Flexstar® GT 3.5 are applied before weeds reach 4 inches tall. Using two different modes of action and containing Isolink® II Technology, Flexstar GT 3.5 optimizes the systematic activity of glyphosate and contact activity of fomesafen to help protect yield potential.

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