Transcript Slide 1

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
– 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
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!