Palmer Amaranth Identification During Flowering - August 21, 2023 - Amy Timmerman - Extension Educator
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- [0:00] This is Amy Timmerman with Nebraska Extension.
- [0:03] This is a great time of year to scout for Palmer Amaranth in crop fields.
- [0:07] While Palmer Amaranth has be identified in several Nebraska counties
- [0:11] and new identifications have slowed since the wide spread
- [0:15] introduction on non-crop areas since 2016.
- [0:18] However, new Palmer Amaranth introduction are still being found in Nebraska fields.
- [0:23] Highlighting the importance for farmers and agribusiness
- [0:25] professionals to remain vigilant in scouting for these species.
- [0:30] A native of the American southwest, Palmer Amaranth is more competitive
- [0:34] than Common Waterhemp, a pigweed native to Nebraska.
- [0:38] Both species are known for prolonged emergence, fast
- [0:41] development of herbicide resistance, and prolific seed production where
- [0:46] plants can produce greater than 500,000 seeds per plant.
- [0:50] Palmer Amaranth was added to Nebraska's Noxious Invasive species
- [0:54] program, highlighting it's potential threat to Nebraska agriculture.
- [0:59] Early identification is key to eradicating this weed from fields.
- [1:03] Eradication can not happen without vigilance, early detection, and an
- [1:07] appropriate response soon after it invades an area.
- [1:11] Palmer Amaranth should be starting to flower, making it
- [1:14] much easier to distinguish it from Waterhemp.
- [1:17] In addition to fields where Palmer Amarath was found previously,
- [1:21] other priority areas to scout include farms that use feed and bedding
- [1:25] from southern states, fields receiving manure from those farms, and farms
- [1:30] where out of state equipment or been used in fields with previous
- [1:34] history of Palmer Amaranth has been has been used.
- [1:37] Palmer Amaranth and Waterhemp lack hair on stems and leaves.
- [1:41] While other Common Amaranth and Pigweed species have hair on stems or leaves.
- [1:47] Early in the growing season, Palmer Amaranth
- [1:49] is difficult to differentiate from Waterhemp
- [1:52] due to the high variability in both species.
- [1:55] The most reliable vegetative trait to differentiate Waterhemp and
- [1:59] Palmer Amaranth is that some but not all Palmer Amaranth leaves
- [2:04] have a petiole longer than the leaf blade.
- [2:07] Leaves on Palmer Amaranth are often clustered tightly at the top of the plant
- [2:11] and Palmer Amaranth often has a denser canopy than Waterhemp.
- [2:16] Palmer Amaranth and Waterhemp produce male and female flowers on separate plants.
- [2:22] Identifying males from females should be simple due to the small black seed produced
- [2:27] by female flowers and the presence of pollen on male plants.
- [2:31] Female Palmer Amaranth are easy to distinguish from Waterhemp
- [2:35] due to the long sharp brackets surrounding the flowers.
- [2:39] If you discover this weed, steps should be taken to
- [2:42] remove all female plants to prevent seed production.
- [2:45] Continued vigilance is imperative to slow the speed in which
- [2:49] Palmer Ameranth invades our state.
- [2:52] If you are questioning your identification of Palmer Ameranth, reach out to your
- [2:56] local extension educator for assistance.
- [2:58] This has been Amy Timmerman with Nebraska Extension.