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