Ag Answers: Pigweed

The Morning Show

Doug Gucker from the U of I extension Office joins the Morning Show and in this week’s Ag Answers, he is discussing the need for farmers to check their fields for pigweed.

Farmers need to be inspecting their fields for any weed escapes within 2 to 3 weeks after planting. This is especially true for weeds in the pigweed or Amaranth family. Two particularly troublesome pigweeds are Tall Waterhemp and Palmer Amaranth, which have and are continuing to develop resistance to herbicides. In Illinois, Tall Waterhemp is resistant to 6 different classes of herbicides and Palmer Amaranth is resistant to 3.

According to Dr. Aaron Hager, our Extension Weed Scientist, farmers need to scout their fields within three weeks of planting. Some fields here in this part of Illinois have been planted two weeks already! If you are seeing small waterhemp or palmer amaranth, for maximum herbicide control they must be sprayed before they reach 4 inches tall. A Palmer Amaranth at 2 inch height will be 4 inches tall in less than 4 days with warm temperatures. Weed scientists across the Corn Belt, including Dr. Hager, are recommending a “zero” tolerance for palmer amaranth escapes. This is due to the fact that one female plant will produce 460,000 Seeds and if you control 95% of those seeds, there is still the potential for 23,000 plants to survive. Scout early, is necessary spray post-emergent herbicide before 4 inches tall. If you herbicide program fails, then cut the plants before they go to seed.

There’s also an ag podcast devoted to corn and soybean farmers here in this part of Illinois. It’s called “Out Standing in the Field” and it’s on SoundCloud.

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