Herbicides for Sugarcane Curtis Rainbolt Everglades REC

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

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

PRE Herbicides

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

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

Evik (Ametryn) Rates Tankmixture: 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

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

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

Prowl + Sencor Good broad spectrum PRE program Rates 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)

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

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

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

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

POST Herbicides

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

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

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

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

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

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)

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

Asulox (Asulam)

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

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

Fallow Land Treatments

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

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!