Several calls have come in about an odd looking weed in peanut and cotton fields. At first you will think a grass species is coming up. Then the leaf begins to broaden. We are seeing Tropical Spiderwort and other types of dayflower all over the county. I pulled out the publication below to give several growers on cotton. It is a few years old but still relevant.
In peanut you have a couple of options as well. The key to both is residual herbicides that combat dayflower—-Dual and Warrant.
SUGGESTED HERBICIDE PROGRAMS FOR THE CONTROL OF TROPICAL SPIDERWORT (BENGHAL DAYFLOWER) IN PEANUT***
PROGRAM 1
a) PRE Immediately After Planting: Valor at 3 oz/A + Dual Magnum 7.62EC or generic metolachlor (Stalwart, Parallel PCS, Me-Too-Lachlor) at 1 pt/A or Warrant 3ME at 3 pt/A or Outlook 6EC @ 12.8 oz/A and
b) POST when spiderwort is 1–2″ tall: Cadre/Impose 2AS at 4 oz/A or Strongarm 84WG at 0.45 oz/A + Dual Magnum 7.62EC or generic metolachlor (Stalwart, Parallel PCS, Me-Too-Lachlor) at 1 pt/A or Warrant 3ME at 3 pt/A or Zidua 4.17SC @ 2.5 oz/A or Anthem Flex 4SC @ 3 oz/A.
* At plant applications of Dual/Warrant/Outlook are more effective for TSW/BD control at later peanut planting dates (May 15 or later) because the majority of emergence occurs after June 1.
PROGRAM 2
a) AT-CRACK (within 28 days after peanut cracking): Apply paraquat 2SL formulations at 12 oz/A A or paraquat 3SL formulations at 8 oz/A Storm 4EC at 16 oz/A or Basagran 4EC @ 8 oz/A + Dual Magnum 7.62EC or generic metolachlor (Stalwart, Parallel PCS, Me-Too-Lachlor) at 1 pt/A or Warrant 3ME at 3 pt/A or Zidua 4.17SC @ 2.5 oz/A or Anthem Flex 4Sc @ 3 oz/A and
b) POST (~2–3 weeks after at-crack spray): Apply Cadre/Impose 2AS at 4 oz/A or Strongarm 84WG at 0.45 oz/A + Dual Magnum 7.62EC or generic metolachlor (Stalwart, Parallel PCS, Me-Too-Lachlor) at 1 pt/A or Warrant 3ME at 3 pt/A or Zidua 4.17SC @ 2.5 oz/A or Anthem Flex 4SC @ 3 oz/A.
* When using Dual Magnum/generics or Outlook in combination with Cadre/Impose, paraquat, or Strongarm, additional spray adjuvants (NIS, COC) are not necessary.
The maximum amount/A/year of Dual Magnum that can be applied is 2.8 pt/A. The maximum amount/A/year of Stalwart, Parallel PCS, or Me-To-Lachlor that can be applied is 2.66 pt/A.
The maximum amount of Warrant that can be applied PRE + POST is 6 pt/A/year.
Maximum amount of Zidua that can be applied is 4 oz/A/year of 85WG or 6.5 oz/A/year of 4.17SC. When Warrant or Zidua is applied POST, a NIS (0.25% v/v) is needed.
Maximum amount of Outlook that can be appplied is 21 oz/A/year. Maximum amount of Anthem Flex that can be applied is 9.12 oz/A/year.
** Zidua/Anthem Flex should not be applied prior to peanut emergence due to potential injury concerns.
***Twin rows and conventional tillage (plowing) are also useful for the management of tropical spiderwort/ Benghal dayflower.
(Source: 2021 UGA Pest Management Handbook)