Peanut farmers often come up a day late and a dollar short when it comes to the control of Tropical spiderwort, or Benghal dayflower (dayflower). I receive calls each year about harvest aid applications after the herbicide program completely failed. Dayflower control from mid to late season herbicide applications have proven to be inconsistent, which is directly related to size at the time of treatment. A consistent cause of failure is spraying Cadre/Impose too late, hoping for control of all emerged weeds. However, dayflower control is very poor when weeds are greater than 1-2″ tall. Farmers need to scout fields, correctly identify weeds, and make timely control applications in order to successfully control dayflower.
Research has shown 90% control with an “at cracking” program. The preferred herbicide program is a multi-step approach including Paraquat + Dual Magnum or generic Metalachlor at cracking. This application may be applied up to 28 days after emergence, but must be on 1-2″ tall plants. A timely application of Strongarm + 2, 4-DB or Cadre/Impose +2,4-DB 14 days following the Paraquat application will likely finish the job. Additional Dual Magnum or generic Metolachlor is also recommended with this application. This should hold dayflower until the peanut plants have shaded the soil.
The maximum amount of Dual Magnum that can be applied is 2.8 pts/A/year. The maximum amount of generic Metolachlor is 2.66 pts/A/year.
Posted by Sarah Chambers, Extension Intern.
Benghal Dayflower, Identification and Control https://edis.ifas.ufl.edu/ag230
2009 UGA Peanut Weed Control Update www.caes.uga.edu/commodities/fieldcrops/peanuts/2009peanutupdate/weedcontrol.html