Herbicides for Sugarcane

1. Herbicides for Sugarcane Curtis Rainbolt Everglades REC

2. Herbicide Basics • What is the application timing • Common sugarcane timing • PRE • Applied prior to weed and crop emergence • Generally soil active herbicides (some exceptions) • POST • Applied after weeds have emerged • Can be early, mid, late • Generally over-the-top • Generally more foliar active herbicides

3. Herbicide Basics • What is the application timing • Common sugarcane timing • Post-Direct/Lay-by • Applied after sugarcane is fairly large • Direct herbicide at base of plant • Generally for herbicides that cause crop injury • Can be foliar or soil active (or both) • Non-Crop/Fallow • Generally foliar active • Can help with hard to control weeds

4. PRE Herbicides

5. Atrazine • Backbone of sugarcane weed control • Used both PRE and POST • PRE • Good soil activity (2-4 qt/A) • Controls most broadleaves • Suppress/control many grasses • Activity begins to fade 3-5 weeks after application • Broadleaf activity last longer than grass activity

6. Evik (Ametryn) • Generally applied POST, but some PRE • Controls many small grasses and broadleaves • Needs to be less than 4 inches • Less than 3 inches for alexandergrass • Crop injury • More common with higher rates and warmer temperatures

7. Evik (Ametryn) • Rates • 0.5-1.5 lb/A (labeled) • Lower rates often used • Efficacy? • Tankmixture: • Often tank mixed with atrazine (2-4 lb/A) at 0.25 to .75 lb/A

8. Prowl H2O and Prowl 3.3 (Pendimethalin) • Used on moderate acreage • Excellent grass control • Can be season-long under good conditions • Not so good on broadleaves • Tank-mix with Sencor (metribuzin) helps • Still may need follow-up for spiny amaranth

9. Prowl (Pendimethalin) • Challenges • Needs rainfall/soil moisture for activity • Can be good when soil is dry • More consistent when soil moisture is good • Rates • Sand • 2.4-3.6 qt/A • Muck • 2.4-4.85 qt/A

10. Prowl + Sencor • Good broad spectrum PRE program • Muck soil only!!! • Ideally, don’t cultivate if there aren’t weeds • Some broadleaves can come through • Spiny pigweed • Expensive • Can be very good with good soil moisture • Rates • Prowl (4 qt/A) • Sencor (1 lb/A)

11. K4 • Registered for FL sugarcane in 2005 • Mixture of hexazinone (Velpar) and diuron (Karmex) • Applied at 2-4 lbs/A • Higher rates for muck soils, lower on sand • Good control of many grass and broadleaf weeds • Can go out early POST • Apply to cane less than 18 inches tall

12. Diuron(Karmex/Direx/Etc) • Not used much • Sand soils (binds very strongly on muck) • Better control of broadleaves than grass • Not much experience • Crop injury? • Rate • 1.6 lb/A PRE

13. Roundup Ultramax(Glyphosate) • MUST BE APPLIED PRIOR TO CANE EMERGENCE!!!!!!!! • Excellent control of emerged weeds • Excellent control of sugarcane if emerged! • Timing is very, very critical • Controls some hard to manage species • Bermudagrass • Paragrass • Rate • 3.25-4 qt/A

14. Valor(Flumioxazin) • PRE/POST-Direct • Good broadleaf control PRE • Grass control has been variable • Active POST on small grass and broadleaves • High levels of burn on sugarcane • Post-direct only • Cannot be applied over the top of sugarcane

15. POST Herbicides

16. Atrazine • POST • Use with crop oil concentrate • Rate still 2-4 qt/A • Controls many small broadleaves • Grass needs to be small • 3 inches of less is ideal • Provides residual activity

17. Envoke (Trifloxysulfuron) • Applied at 0.3 to 0.6 oz/A • POST, ratoon sugarcane only • Excellent nutsedge product • Good control of small broadleaves • Controls some small grasses • Excellent on alligatorweed, spiny amaranth • Looks good in combination Asulox/Asulam at 0.5 gallon/A • Good, wide spectrum treatment

18. 2,4-D Amine • Very versatile, useful product • Controls most broadleaves • Can use lower rates on smaller weeds • Can suppress nutsedge growth • Probably not long-term control • Alligatorweed activity can be good • Need good conditions for best control

19. 2,4-D Amine • Challenges • Can drift and volatilize • Major problems!!!! • Follow the Florida Organo-Auxin Rule • No volatile formulations (esters) • Application restrictions based on wind speed • Also distance from sensitive crops • http://edis.ifas.ufl.edu/WG051

20. 2,4-D Amine • Rates • 0.5 to 2.0 lb ai/A • Note rates in ai due to many formulations • Lower end will control many small weeds • Higher rates for alligatorweed, large weeds

21. Asulox(Asulam) • Excellent POST grass herbicide • Controls most common grasses • Size of weeds is important • Can use 6 pt/A if grass is 6-8 inches or less • Preferably less! • Use 1 gal/A (8 pt) is grass is greater than 8 inches • Use a surfactant (0.25% v/v) or COC (1% v/v)

22. Asulox(Asulam) • Challenges • Good spray coverage is very important • Many control issues relate to coverage • Use the proper rate • If it’s 6 inches today, it will probably be 8 inches next week • Slow activity • Need to be patient • Injury • We can see burning to leaves at higher rates • Can use a directed application

23. Asulox(Asulam)

24. Evik (Ametryn) • Controls many small grasses and broadleaves • Needs to be less than 4 inches • Less than 3 inches for alexandergrass • Directed application • Injury will be seen on treated foliage • Use surfactant at 0.5% v/v • Rates • 0.5-1.5 lb/A • Lower rates often used

25. Sempra, Sandea (Halosulfuron) • Excellent nutsedge control • Yellow and purple (4-12 inch ideal) • Works best under good moisture conditions • Controls some small broadleaves • Small pigweed, ragweed (less than 4 inches) • Use surfactant or COC • 0.25-0.5% v/v surfactant or 1% COC v/v • Rate • 1 to 1.33 oz/A

26. Fallow Land Treatments

27. Glyphosate • Excellent control of emerged weeds • Controls many hard to manage species • Bermudagrass • Paragrass • Napiergrass • Nutsedge (better on yellow) • Many, many others

28. Take Home • Always follow the label!!! • Several effective herbicides • Identify weed spectrum • Apply correct rate • Apply to correct weed size • Let the herbicide work! • We will hopefully have more options in the future!