Using DiFlexx® Herbicide in Corn

What is DiFlexx® herbicide?

DiFlexx® herbicide is a dicamba-based herbicide (herbicide group 4, growth regulator mode of action) registered for control of broadleaf weeds in field corn grown for grain, seed, silage, or popcorn, and for fallow cropland. Plants absorb this herbicide through their leaves, shoots, and roots. DiFlexx® herbicide contains a safener, cyprosulfamide, a Crop Safety Innovation (CSI™) Safener technology which enables corn plants to withstand herbicidal activity and can lead to increased root growth and plant health. It can be used sequentially or in approved tank mixes. It is formulated as a suspension concentrate containing four pounds acid equivalent (a.e.) per gallon.¹

Which weed species are controlled by DiFlexx® herbicide?

DiFlexx® herbicide is labeled for control of over 100 annual broadleaf weeds, including biotypes that have known resistance to one of more of the following: glyphosate, triazine, PPO inhibitors, ALS inhibitors, or HPPD inhibitors. Annual broadleaves listed on the label for control include Palmer amaranth, cocklebur, henbit, kochia, common lamb’s-quarter, mare’s tail (horseweed), ivyleaf morningglory, black nightshade, field pennycress, pigweed species, common and giant ragweed, common sunflower, velvetleaf, and waterhemp. DiFlexx® herbicide is also labeled to control more than 50 perennial broadleaves including field bindweed, hedge bindweed, and Canada thistle.¹

In a study conducted in southcentral Nebraska, DiFlexx® herbicide provided excellent control of Palmer amaranth that resisted atrazine and HPPD-inhibiting herbicides. In this study, DiFlexx® herbicide was applied early postemergence following a pre-emergence application of Corvus® herbicide. The Palmer amaranth was less than 4 inches tall when DiFlexx® herbicide was applied.²

What advantages does DiFlexx® herbicide potentially have compared to a dicamba-based herbicide product without a safener?

Research conducted in 2020 at Bayer’s Gothenburg Learning Center at Gothenburg, Nebraska compared the influence of an unsafened dicamba formulation, Sterling Blue® herbicide, to DiFlexx® herbicide for percent (%) greensnap and yield. Each were each applied at 16 fl oz/acre on 06/24/2020 in combination with Delaro® 325 SC fungicide, Roundup PowerMAX® at 32 fl oz/acre, and ammonium sulfate (AMS) at 17 lb per 100 gallon, at the V6 growth stage.

Five corn products ranging from 104 relative maturity (RM) to 113 RM were tested in irrigated conditions. Two of the products had growth regulator herbicide injury ratings of CAUTION while the other three products were rated as ACCPETABLE.

Averaged across the corn products in the study, DiFlexx® herbicide significantly reduced the percent greensnap compared to the unsafened product (6.1% vs 13.8%, respectively, LSD 0.1 = 4.1%). The range of greensnap was from 2.4% to 12.4% across the corn products treated with DiFlexx® herbicide, while greensnap values as high as 22.4% were observed with the unsafened dicamba herbicide product.

Average grain yield was significantly higher across all corn products treated with DiFlexx® herbicide (250.0 bu/acre) than with the unsafened formulation (235.7 bu/acre, LSD 0.1 = 13.7 bu/acre).³

Can DiFlexx® herbicide be used pre-plant or pre-emergence in corn, and what are the application rates?

DiFlexx® herbicide can be used in any tillage system as pre-plant, pre-emergence, or post-emergence applications. It can be applied pre-plant or pre-emergence at eight to 16 fl oz/acre up to 14 days before, during, or after planting corn. Corn should be planted at least 1.5 inches deep and the corn seed should be completely covered with soil.¹

What are the application rates and timing for post-emergent use of DiFlexx® herbicide in corn?

Post-emergent, broadcast applications should be made when the weeds are actively growing and the growth stage of the corn is from spike (emergence) through the V10 (10 leaf collars) growth stage or 36 inch tall, whichever comes first. Application rates range from six to 16 fl oz/acre. Rates below eight fl oz/acre will help manage certain broadleaf weeds but should be applied in a tank mixture with permissible, effective postemergence herbicides for approved weed management. Small, actively growing weeds (one to three inches tall) are generally more easily managed than larger weeds. Prior to application, verify the selectivity of DiFlexx® herbicide on the inbred line or corn product.¹

Application rates for use in corn are limited to no more than 16 fl oz/acre per application, while the maximum amount per growing season is 24 fl oz/acre. Only two applications can be made to corn per growing season and must be separated by two weeks or more.¹

What are some of the application instructions, precautions, or restrictions according to the label?

Water should be used as the carrier (do not use fluid fertilizer post-emergent). Select drift-reducing nozzle tips that will provide a coarse droplet size of 400 microns or more at a pressure of 20 pounds per square inch (psi) or less. Application should occur when wind speeds are between two to 10 miles per hour (mph) to manage drift potential. To improve weed control, especially in dry growing conditions, one of the following surfactants may be added:

• Nonionic surfactant (NIS) at 1 quart per 100 gallons of spray solution (.25% v/v).
• Crop oil concentrate (COC) or methylated seed oil (MSO) at a rate of 1 gallon per 100 gallons of solution (1.0% v/v).

If tank mixing with other products, review their adjuvant recommendations and follow the most restrictive label. Bayer strongly recommends the inclusion of an approved drift reducing agent (DRAs) plus a VaporGrip® Xtra Agent Product or approved volatility reducing agent in the tank mix.

DiFlexx® herbicide is rainfast in four hours following application, so overhead irrigation should be delayed at least that long. Application through any type of irrigation system is prohibited. The restricted-entry interval (REI) is 24 hours after application. The pre-harvest interval (PHI) for harvesting corn as forage is 45 days after the final DiFlexx® herbicide application. Corn grain and stover may be harvested if the crop has reached the milk stage (R3 growth stage).¹

What are some permissible tank-mix herbicide options with DiFlexx® herbicide that can provide additional weed management?

There are several permissible tank-mix partners available from Bayer Crop Science that may help provide additional weed management. They include:¹

• Autumn™ Super 51 WDG herbicide
• Balance® Flexx herbicide
• Capreno® herbicide
• Corvus® herbicide
• Laudis® herbicide
• Roundup® brand agricultural herbicides

What is the specific mixing order for using DiFlexx® herbicide with a permissible tank-mix partner?

1. Fill the sprayer tank about ¾ full of clean water and maintain agitation throughout the mixing process.
2. Add herbicide products packaged in water soluble PVA packets.
3. Add DiFlexx® herbicide and other water-dispersible products such as dry flowable, wettable powders or suspension concentrates.
4. Add water soluble products.
5. Add emulsifiable concentrates.
6. Add water soluble additives.
7. Fill the remaining volume of the tank with water.

Are there planting/replanting restrictions after applying DiFlexx® herbicide?

Yes. Corn can be replanted immediately after an application of DiFlexx® herbicide. Caution should be used to ensure that the seed does not come into direct contact with the herbicide. The rotational interval to soybeans is application rate dependent. If DiFlexx® herbicide is applied to corn at 12 fl oz/acre or less, the interval before planting soybeans should be 30 days. The interval is 60 days for application rates of 13 to 24 fl oz/acre. The rotational interval for planting barley, cotton, oats, sorghum, or wheat is 60 days. All other crops have a 120-day rotational interval.¹

Always read and follow label instructions. The complete label for DiFlexx® herbicide can be found at DiFlexx1v_Labelpdf (bayer.com).

Sources

¹Bayer Crop Science. DiFlexx® herbicide label. EPA Reg. No. 264-1173. https://cs-assets.bayer.com/is/content/bayer/DiFlexx1v_Labelpdf
²Jhala, A. 2015. DiFlexx™: A new dicamba-based corn herbicide. University of Nebraska Extension. Cropwatch. https://cropwatch.unl.edu/diflexx-herbicide
³Bayer Crop Science. 2021. Dicamba formulation impact on corn. https://www.corn-states.com/app/uploads/2021/01/4024_R1_20_BA_Dicamba-Formulation-Impact-on-Corn_BA.pdf
Web sources verified 09/12/2024. 1226_446100