Sedges have exploded across Arkansas in 2019 throughout different cropping systems.
Additionally, a variety of unique sedge species have made themselves known this year, and others have popped up in areas where sedges have not previously been an issue.
These unique sedges are problematic as not all are created equal when it comes to controlling them with different herbicides. Add to that the fact that certain populations are ALS resistant (Figure 6), and options to control sedges in rice quickly become limited.
If you are having issues with sedges in your rice fields, a proper identification of the sedge species is required to better select herbicides for control. There are a couple of resources available to assist with sedge identification.
First, fact sheet FSA 2173 is available at https://www.uaex.edu/publications/pdf/FSA-2173.pdf. This publication helps identify differences between yellow nutsedge, rice flatsedge, umbrella sedge and swamp sedge.
The second sedge identification resource is a sedge image database found at https://plants.uaex.edu/weed_id/display_category.aspx?category=Sedge.
The best course of action to control the sedges present in the rice field will be determined on a situational basis. What specific sedge was identified in the field? Is the population ALS inhibitor-resistant? Is Loyant an option? These situations will affect the best management strategy.
Control of yellow nutsedge is very reliant on ALS-inhibiting chemistries. Newpath in a Clearfield rice system or products containing Permit (Permit, Permit Plus, Gambit) should control yellow nutsedge. Umbrella sedge can be controlled with a tankmix of Basagran plus propanil, and in situations that allow it, Loyant has shown to provide excellent control.
Annual and rice flatsedges have the most control options available. Most ALS-inhibiting chemistries provide control of flatsedges such as Newpath/Beyond in Clearfield systems, products containing Permit, Strada and Regiment.
However, in instances where ALS-inhibitor resistance is possible, other options such as Basagran, propanil and Loyant provide excellent control of flatsedge. If prior to flood, Sharpen provides post control of flatsedges and will add some residual activity.
Unique sedges outside of yellow, umbrella and flatsedge will require some additional effort for control. Our best recommendation is to use a broad-spectrum sedge control program tankmixing multiple herbicides such as Loyant plus Gambit or Basagran plus propanil plus Gambit.
As data is limited on controlling these unique sedges, a tankmixture program will help to cover all bases. Good luck out there, we can survive the sedge-pocalypse!
University of Arkansas Division of Agriculture Research & Extension contributed this article.