Pigweed ID

Transcript

1. WEED ID REFRESHER: Pigweed species Joe Armstrong Oklahoma State University Weed Science www.weedscience.okstate.edu Twitter: @OSUWeedSci
2. Generally speaking, identification of individual pigweed species is not necessary to choose the correct herbicide for maximum control. However, due to the development of herbicide-resistance in populations of waterhemp and Palmer pigweed in Oklahoma and the US, it is increasingly important to properly identify each weed to develop an appropriate management strategy.
3. All pigweeds, regardless of species, typically have a small notch in the tip of the true leaves. © Joe Armstrong, Oklahoma State University
4. © Joe Armstrong, Oklahoma State University Seeds of the various pigweed species are small, brown or black, round, and shiny. Because of their size, the seeds are easily moved in soil, with seed, or on equipment
5. redroot pigweed Redroot pigweed has wide, egg-shaped leaves © Joe Armstrong, Oklahoma State University
6. redroot pigweed Note the short hairs on the stem. © Joe Armstrong, Oklahoma State University
7. waterhemp Waterhemp has long, slender leaves. © Joe Armstrong, Oklahoma State University
8. waterhemp The leaves are very waxy and shiny. © Joe Armstrong, Oklahoma State University
9. Palmer pigweed Palmer pigweed has wide, egg-shaped leaves. Often, they will have a white or purple “V” watermark. © Joe Armstrong, Oklahoma State University
10. Palmer pigweed Palmer pigweed also has waxy, shiny leaves. Note the absence of the watermark. © Joe Armstrong, Oklahoma State University
11. Palmer pigweed Unlike redroot pigweed, Palmer pigweed has a smooth, hairless stem. © Joe Armstrong, Oklahoma State University
12. Palmer pigweed waterhemp Palmer pigweed can also be identified by the long petiole, or the stalk that connects the leaf blade to the stem. This causes the leaves to hang out far away from the main stem. © Joe Armstrong, Oklahoma State University
13. Palmer pigweed Seedheads on Palmer pigweed plants are usually 1-2 feet in length. © Joe Armstrong, Oklahoma State University
14. tumble pigweed Tumble pigweed is usually the easiest pigweed species to identify. As the name suggests, it grows in a low, round shape. © Joe Armstrong, Oklahoma State University
15. tumble pigweed Tumble pigweed also has more rounded leaf tips and wrinkled leaf margins than the other pigweeds. © Joe Armstrong, Oklahoma State University
16. redroot pigweed waterhemp Palmer pigweed tumble pigweed © Joe Armstrong, Oklahoma State University
17. All photos, unless noted, were taken by Joe Armstrong. If you would like high resolution versions of these photographs, please contact Joe at joe.armstrong@okstate.edu.