New Soybean Herbicides for 2021
One of my goals in posting articles on this website is to inform producers about new products that will be available for them to use in their soybean production systems in the coming growing season.
Thus, the subject of this article is to provide details about two new herbicide products that producers can use in their battle against troublesome weeds that plague Midsouth soybeans. Since I am not privy to proprietary information pertaining to the performance of these products, I will provide a summary of their pertinent points as stated on their labels or originating company’s fact sheets. Additional information about the utility of these products can likely be obtained from state weed scientists and Extension specialists who may have seen them used in the field.
Kyber (from Corteva) is a new premix of metribuzin (Group 5–e.g. Sencor), flumioxazin (Group 14–e.g. Valor), and pyroxasulfone (Group 15–e.g. Zidua) active ingredients. It is intended for preemergence (PRE) weed control in soybeans, and can be applied up to 3 days after planting and prior to soybean emergence.
The Kyber Herbicide Fact Sheet states that the following grass and broadleaf weeds (among others) are controlled by the herbicide.
• Grasses–barnyardgrass, crabgrass, southwestern cupgrass, seedling Johnsongrass, fall and Texas panicum, Italian ryegrass, and broadleaf signalgrass.
• Broadleafs–cutleaf evening primrose, hemp sesbania, henbit, marestail, Palmer amaranth and 5 other pigweed species, prickly sida or teaweed, and smallflower morningglory.
Kyber is rainfast one hour after application. It has a 12-month rotational restriction for rice, which is commonly grown in rotation with soybean in the Midsouth. The rotational interval for wheat planted after soybean is 8 months, so it should not be used if doublecropping soybean and wheat is planned. However, it has no restriction that will affect a biennial corn-soybean rotation. Its active ingredients are the same as those in Fierce MTZ, but the concentrations of each may be different between products. Since one component of this herbicide mix is metribuzin, click here to check for soybean varieties that may be sensitive to this component.
According to Corteva, the product is undergoing state-by-state approvals at this time. A label for the product is forthcoming, and sales of the product are intended to start in Nov. 2020.
Reviton (from Helm) is a PPO-inhibitor herbicide with the active ingredient Tiafenacil (Group 14) that is intended for preplant burndown use in soybean. It is a non-selective contact herbicide that is to be used to control or suppress a broad spectrum of emerged broadleaf and grass weeds (click here for a list of 23 target weeds). Its burndown activity is best when applied to young (generally less than 5 in. tall) annual weeds. It suppresses the growth of perennial weeds by desiccating green foliage. It must be applied with an adjuvant (methylated seed oil/crop oil concentrate or nonionic surfactant) for optimum burndown activity. It has no PRE activity.
At the 1, 2, or 3 fl. oz./acre application rates, the interval between application of Reviton and planting of labeled crops or replanting after crop failures is 0 days for wheat and corn and 14 days for soybean and cotton. It is not to be applied by air or through any type of irrigation system. The minimum spray volume for Reviton applications is 10 gal./acre. As with all herbicides, the use of Reviton should be rotated with herbicides of other groups that control the same weeds in a field.
Important point: the above are new herbicide products that contain currently available active ingredients or active ingredients with currently available modes of action–i.e., they do not contain active ingredients with new modes of action. Therefore, they should be considered a part of the arsenal of herbicides that is available to control targeted weeds, especially those such as Palmer amaranth that are troublesome in Midsouth soybean production systems.
Composed by Larry G. Heatherly, Oct. 2020, larryheatherly@bellsouth.net