Herbicides for Sugarcane

Calvin Odero

Everglades REC

Belle Glade

Herbicide Basics

• What is the application timing– Common sugarcane timing

• Preemergence (PRE)– Applied prior to weed and crop emergence– Generally soil active herbicides (some exceptions)

• Postemergence (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 certain 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– Weeds need 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– 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 (Pendimethalin)

• Used on moderate acreage– Excellent grass control

• Can be season-long under good conditions (incorporation by rainfall)

– Not so good on broadleaves• Tank-mix with metribuzin helps• Still may need follow-up for spiny amaranth

Prowl H2O (Pendimethalin)

• Challenges– Needs rainfall/soil moisture for activity– Can be good when soil is moist

• More consistent when soil moisture is good

• Rates– Sand

• 2.4-3.6 qt/A

– Muck• 2.4-4.85 qt/A

Prowl + Metribuzin

• Good broad spectrum PRE program– Muck soil only!!!– Ideally, don’t cultivate if there aren’t weeds– Some broadleaves can come through

• Spiny amaranth

– Expensive– Can be very good with good soil moisture

• Rates– Prowl (4 qt/A)– Metribuzin (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• Not currently used in Florida

Diuron (Direx, others)

• 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

Glyphosate (several trade names)

• 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

• Not currently used in Florida

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 for fall panicum control– 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– For vine control later in the season

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 (0.25 lb/A) often used

• Efficacy?

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

Callisto (Mesotrione)

• Applied POST at 3 fl oz/A for broadleaf weed control – Reduces atrazine dependence – May reduce the need for 2,4-D – Reduces amount of herbicide applied per acre – Minimizes broadleaf weed escapes

Callisto (Mesotrione)

• Low use rate – Greatly reduces chemical storage, transportation and

handling • 1 gal of Callisto (3 fl oz rate) will treat 42 acre • Takes 31.5 gals of Atrazine 4L (3 lb ai/A rate) or 35 lbs of AAtrex

Nine-O to treat 42 acres

– Reduces container disposal, handling – Reduces environmental risks

• Tank-flexibility – Tank-mix with Atrazine 4L (1 qt/A) or Aatrex Nine-O (1.1

lb/A), Evik (0.25-0.75 lb/A) – Envoke, Asulam

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!

Contact Information

Calvin Odero

Extension Weed Specialist & Assistant Professor

Everglades Research & Education Center

3200 E Palm Beach Road

Belle Glade, FL 33430

Phone: 561-993-1509

Email: dcodero@ufl.edu