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Publication #SS-AGR-09

Weed Management in Sugarcane1

D. C. Odero and J. A. Dusky2

Successful weed control is essential for economical sugarcane production in Florida. Weeds can reduce sugarcane yields by competing for moisture, nutrients, and light during the growing season. Several weed species also serve as alternate hosts for disease and insect pests. Weed control is most critical early in the season prior to sugarcane canopy closure over the row middles. Heavy weed infestations can also interfere with sugarcane harvest by adding unnecessary harvesting expenses. A weed that is allowed to mature and produce seed will multiply weed control problems by being a source of seed bank replenishment and re-infestation in subsequent years. See Table 1 for available herbicidal options.

Figure 1. 

Sugarcane crops being cleared of weeds.


Credit:

Thomas Wright, UF/IFAS.


[Click thumbnail to enlarge.]

Crop Rotation

Crop rotation patterns will affect weed management of a sugarcane crop. Weed management must be intensified particularly in successive planting operations. Traditionally, the fallow period between final ratoon harvest and planting has effectively been used to manage troublesome perennial weeds such as Bermudagrass. This is accomplished primarily by a combination of mechanical cultivation and herbicide application. Flooding fallow fields also aids in weed control through the development of an anaerobic environment in which weed seed germination and seedling growth is inhibited. Under successive planting management, weed populations are not severely reduced between crops and weed pressure will increase if adequate control measures are not implemented.

Figure 2. 

Sugarcane field in Immokalee, Florida.


Credit:

Josh Wickham, UF/IFAS.


[Click thumbnail to enlarge.]

Crop Competition

Crop competition for sunlight is one of the most important concepts to be utilized in effective weed control. A good stand of sugarcane that emerges rapidly and uniformly and forms a complete canopy that shades the row middles early in the season is very helpful in reducing weed competition. The loss of sugarcane stools in ratoon crops due to rodent, insect, or harvest damage will create open spaces in the sugarcane canopy in which weeds can proliferate. A concentrated effort to maintain maximum sugarcane populations throughout all phases of production will benefit weed control efforts.

Cultivation

Cultivation can be an economical means of suppressing weed growth. To ensure that the sugarcane plants get the early advantage in the competition for sunlight, a height differential must be established between cane plants and weeds. Preemergence (PRE) herbicides are most effective in establishing this height differential. Only when the sugarcane plants are growing taller than competing weeds can mechanical cultivation be effective. However, cultivation when weeds are not present due to application of a herbicide or previous cultivations are not recommended. Cultivation when weeds are not present can encourage germination of additional weed seeds, and can remove the layer of herbicide present when soil-applied herbicides are used. In ratoon crops, mechanical cultivators must be able to cut through surface debris and thoroughly mix the soil.

Herbicides

Herbicides can be useful and economical tools in sugarcane production. They must be incorporated into an overall management plan to obtain their maximum benefit. It is important that sugarcane plants have the initial competitive advantage against weeds. PRE herbicide applications, in conjunction with mechanical cultivation, help to ensure the early season advantage. Directed or semi-directed postemergence (POST) herbicide applications can generally only be effective if the sugarcane is taller than the competing weeds. Accurate herbicide placement is crucial for banded or directed applications. High application speeds and rough fields can result in poor application uniformity, particularly with banded applications. Speed must be limited if movement of the boom or drop nozzles results in excessive amounts of herbicide actually depositing in the untreated strip. Broadcast applications are generally less affected by these factors, since nozzle overlap helps ensure uniformity of herbicide placement. Proper timing of herbicide application with respect to the growth stage of the weeds is extremely critical. Normally, weeds should be treated when they are 4 to 8" in height. Read the label for the proper time of application of each herbicide.

The herbicides suggested in this publication are those that have performed well in IFAS research. Herbicide users must read the label and follow all instructions and precautions carefully. Accurate calibration of application equipment is extremely important in providing effective weed control. The effectiveness and economic usefulness of herbicides must be evaluated by each grower for his particular situation. Initial use of these chemicals should be restricted to a limited acreage for familiarization. You are responsible for the performance of the chemicals you use. Herbicides, like any pesticide, should be handled with care. Store herbicides behind locked doors in the original containers with the label intact and separated from seed, fertilizers, and other pesticides.

Tables

Table 1. 

Weed management in sugarcane.

Trade Name & Broadcast Rate/Acre of Product

Common Name and

Broadcast Rate/Acre

of Active Ingredient

Remarks

FALLOW LAND MANAGEMENT

MUCK AND SANDY SOILS

Glyphosate

(several)

(3.25 – 4 qt)

Glyphosate

(4 – 5 lb)

For control of emerged annual and perennial weeds growing in and around sugarcane or in fields to be planted to sugarcane. Apply during fallow intervals preceding planting. Can be used to remove last stubble of sugarcane crop. Control of sugarcane stubble will depend on sugarcane height and herbicide rate. New growth should have at least 7 new leaves at the time of application. Allow 7 or more days after application before tillage. Repeat applications may be made up to a maximum of 8.125 lb ai per acre per year. Apply in 10 to 40 gal of water per acre. Consult the label for specific rates of application for various weeds and low rate technology application.

PREEMERGENCE-PLANT CANE

MUCK SOILS

Aatrex 4L or

Atrazine 4L

(several)

(4 – 8 pt)

or

Aatrex Nine-O or

Atrazine 90DF

(several)

(2.2 – 4.4 lb)

Atrazine 1

(2 – 4 lb)

For control of annual broadleaf and some grass weeds. Broadcast by ground equipment before sugarcane emerges at time of planting or ratooning. Maximum annual rate is 20 pt or 11.1 lb of formulated atrazine product per acre (equivalent to10 lb ai/A of atrazine). No mixing/loading within 50 ft of canals because of ground and surface water concerns. Restricted Use Pesticide.

K-4

(4 lb)

Hexazinone + Diuron

(0.53 + 1.87 lb)

For control of annual grass and broadleaf weeds. Application should be made immediately following planting and row packing, but prior to crop and weed emergence. For best weed control, application should be made to firm, well prepared seedbed free from excess clods or plant residue. When applying K-4 alone or in combination with other diuron containing products, do not exceed 6 lb of diuron per acre. Do not apply more than 7.5 lb per acre per year of K-4 and do not apply K-4 within 234 days of harvest.

Prowl 3.3 EC or

(2.4 – 4.85 qt)

Pendimethalin 3.3

(several)

(2.4 – 3.6 qt)

+

Sencor or

Metribuzin

(several)

(1 – 2.33 lb)

Pendimethalin

(2 – 4 lb)

or

Pendimethalin

(2 – 3 lb)

+

Metribuzin

(0.8 – 1.86 lb)

For control of most annual grasses and broadleaf weeds. Broadcast or band by ground equipment. Apply at time of planting or ratooning, but prior to emergence. Mechanical incorporation or rainfall within 7 days of application is needed to incorporate pendimethalin applied alone or in combination with metribuzin into the soil, or activity will be significantly decreased. Do not exceed 14.4 pt (equivalent to 5.95 lb ai per acre) of pendimethalin or 2.33 lb (equivalent to 1.75 lb ai per acre) of metribuzin per acre in one growing season.

Aatrex 4L or

Atrazine 4L

(several)

(4 – 8 pt) or

(2.2 – 4.4 lb)

+

Sencor

or

Metribuzin

(several)

(1 – 2.33 lb)

Atrazine

(2 – 4 lb)

+

Metribuzin

(0.8 – 1.86 lb)

For control of most broadleaf and certain grass weeds. Broadcast or band by ground equipment. Apply at time of planting or ratooning, but prior to weed emergence. Rainfall within 7 days of application is needed to incorporate the herbicide into the soil, or activity will be significantly decreased. Do not exceed 20 pt or 11.1 lb of formulated atrazine product per acre (equivalent to10 lb ai per acre of atrazine) or 2.33 lb per acre (equivalent to 1.75 lb ai per acre) of metribuzin in one growing season. No mixing/loading of atrazine within 50 ft of canals because of ground and surface water concerns. Atrazine is a Restricted Use Pesticide.

Callisto

(6.0 – 7.7 fl oz)

(0.188 – 0.24 lb)

For control of annual broadleaf weeds. Apply after planting of ratoon sugarcane. If weeds have already emerged at the time of application, add a crop oil concentrate (COC) at 1.0% v/v or a nonionic surfactant (NIS) at 0.25% v/v to the spray solution. UAN at 2.5% v/v or ammonium sulfate (AMS) at 8.5 lb per 100 gal of spray solution can also be added. Refer to label for tank mix partners. Do not apply more than 7.7 fl oz (0.24 lb ai) per acre as a PRE application. Do not make more than two applications per year. Two applications should not be made less than 14 days apart.

PREEMERGENCE-PLANT CANE

SANDY SOILS

Aatrex 4L or

Atrazine 4L

(several)

(4 – 8 pt)

or

Aatrex Nine-O or

Atrazine 90DF

(several)

(2.2 – 4.4 lb)

Atrazine 1

(2 – 4 lb)

For control of annual broadleaf and some grass weeds. Broadleaf weed control will be superior to annual grass weed control. Broadcast by ground equipment before sugarcane emerges. Good soil moisture or light rainfall is essential for improved efficacy. May be used in split application: 4 pt or 2.2 lb of formulated atrazine product (2.0 lb ai) per acre PRE followed by 4 pt or 2.2 lb of formulated atrazine product (2.0 lb ai) per acre as required. Application may be delayed until emergence of small weeds and sugarcane. Maximum annual rate is 17.2 pt or 9.6 lb of formulated atrazine product per acre (equivalent to 8.6 lb ai per acre). No mixing/loading within 50 ft of canals because of ground and surface water concerns. Restricted Use Pesticide.

Direx 4L or

Diuron 4L

(several)

(1.6 – 3.2 qt)

Karmex DF or

Diuron 80/Diuron DF

(several)

(2 – 4 lb)

Diuron

(1.6 - 3.2 lb)

For control of broadleaf and grass weeds. Controls broadleaf better than grass weeds. Broadcast prior to weed emergence. An additional POST spray of 1.6 lb per acre may be applied to prolong weed control. Do not apply more than 6 lb or 4.8 qt of formulated diuron product per acre (equivalent to 4.8 lb ai per acre of diuron) between planting (ratooning) and harvest.

Callisto

(6.0 – 7.7 fl oz)

(0.188 – 0.24 lb)

For control of annual broadleaf weeds. Apply after planting of ratoon sugarcane. If weeds have already emerged at the time of application, add a crop oil concentrate (COC) at 1.0% v/v or a nonionic surfactant (NIS) at 0.25% v/v to the spray solution. UAN at 2.5% v/v or ammonium sulfate (AMS) at 8.5 lb per 100 gal of spray solution can also be added. Refer to label for tank mix partners. Do not apply more than 7.7 fl oz (0.24 lb ai) per acre as a PRE application. Do not make more than two applications per year. Two applications should not be made less than 14 days apart.

MUCK AND SANDY SOILS

Glyphosate

(several)

(3.25 – 4 qt)

Glyphosate

(4 – 5 lb)

For control of emerged annual and perennial weeds growing in and around sugarcane fields prior to sugarcane emergence. Higher rates are to be used for difficult to control weeds. For specific rates of application and instructions for control of various weeds, consult the label. For information concerning low rate technology applications, consult the label.

Prowl 3.3 EC

(2.4 – 4.85 qt) or

Pendimethalin 3.3 (several)

(2.4 – 3.6 qt)

Pendimethalin

(2 - 4 lb)

For control of most annual grasses and certain broadleaf weeds. Apply at time of planting or ratooning, but before weeds emerge. Broadcast or band by ground equipment. May be applied by air. Must be incorporated thoroughly and uniformly either by mechanical incorporation or rainfall within 7 days after application. Do not exceed 14.4 pt (equivalent to 5.95 lb ai per acre) of Prowl 3.3 EC in one growing season.

Prowl H2O

(2.1 – 4.2 qt)

Pendimethalin

(2 – 4 lb)

A microencapsulated formulation of pendimethalin with no odor, reduced staining, and lower use rate than other pendimethalins. Apply at planting before weeds emerge. Weed control is equal to that of Prowl 3.3 formulation. Do not exceed 12.5 pt (equivalent to 5.95 ai lb per acre) of Prowl H20 in one growing season.

Valor SX

(6 – 8 oz)

Flumioxazin

(0.19 – 0.25 lb)

For control grass and broadleaf weeds. May be applied 2 weeks prior to planting and before sugarcane emerges. May be used to assist in POST burndown. Control will be improved with the addition of 1.25% v/v COC or methylated seed oil (MSO) or 0.25% v/v of NIS. Residual activity is reduced when applied to soils with more than 10% organic matter. Refer to the supplemental label for sugarcane for more information. Do not apply more than 8 oz per acre per application (equivalent to 0.255 lb ai per acre). Do not apply more than 12 oz per acre per growing season (equivalent to 0.255 lb ai per acre). Do not apply within 90 days of harvest. Refer to the supplemental label for sugarcane for more specific information.

PREEMERGENCE-RATOON CANE

MUCK AND SANDY SOIL

After fertilization, cultivate row middles and then apply selected herbicide listed above for plant cane crops. Apply before or soon after stubble regrowth. Cultivate and apply herbicide to trash rows when trash has decomposed, if practical. Tillage machinery should not throw weedy soil onto chemically treated areas.

PREEMERGENCE-RATOON CANE - MUCK SOIL

K-4

(4 lb)

Hexazinone + diuron

(0.53 + 1.87 lb)

For control of annual and broadleaf weeds. Applications should be made immediately following harvest or prior to subsequent weed germination. Excess plant residue on the soil surface may decrease the effectiveness of K-4 and should be removed or minimized. May be applied POST to stubble sugarcane until the crop reaches a height of 18” or within 234 days of harvest whichever comes first. POST applications of K-4 to actively growing sugarcane may result in crop injury when daily temperatures exceed 80° F. When daily temperatures exceed 80° F, post-directed applications are recommended. If weeds are present at application, a tank-mix partner is recommended for improved POST control. If K-4 is used in a tank mixture with other herbicides, read and follow all use instructions, warnings and precautions on companion herbicide labels. If weeds are present at the time of application use of 0.25% v/v of NIS or 1% v/v of COC is recommended. If a tank-mix partner is being used, follow the most restrictive adjuvant recommendation.

POSTEMERGENCE

MUCK SOILS

Sencor DF

(1.33 – 2.66 lb)

metribuzin 1

(1.0 – 2.0 lb)

For control of pigweeds, butterweed, cudweed, common purslane, goosegrass, and broadleaf panicum. Should be used as directed spray before row closing when weeds are less than 6 inches tall. Avoid contact with sugarcane foliage. Do not use on sugarcane grown in sandy soil.

MUCK AND SANDY SOILS

2,4-D Amine2

(several)

2,4-D

(0.5 – 2.0 lb)

For control of many broadleaf weeds including spiny amaranth, ragweed, and morningglory. Use high rates for large or difficult-to-control weeds, such as alligatorweed. When tank mixing products that contain 2,4-D do not exceed a combined total of 4 pt per acre pre crop cycle. Take care to prevent spray drift to sensitive crops, and consult the Florida Organo-Auxin herbicide rule prior to application.

2,4-D Amine +

Dicamba2

(several)

(2-6 pts)

2,4-D + Dicamba

(0.97 – 2.9 lb)

For control of many annual, biannual, and perennial broadleaf weeds. Apply anytime after weed emergence but prior to close-in stage. When possible direct spray beneath the sugarcane canopy to minimize injury and maximize spray coverage of weed foliage. Use 2 pt per acre for control of annual weeds, and up to 6 pt per acre may be used for difficult to control perennial weeds in a single application (sugarcane injury may occur at 4-6 pt per application). Retreat as needed, but do not exceed 16 pt per acre per growing season. Take care to prevent spray drift to sensitive crops, and consult the Florida Organo-Auxin herbicide rule prior to application.

Aatrex 4L or

Atrazine 4L

(several)

(4 – 8 pt)

or

Aatrex Nine-O or

Atrazine 90DF

(several)

(2.2 – 4.4 lb)

Atrazine 1

(2.0 – 4.0 lb)

Semi-directed spray preferred when weeds are have less than 3 expanded leaves (before exceeding 1.5 inches in height). With good soil moisture or light rainfall, this treatment will provide some residual control of annual and broadleaf weeds especially on sandy soils. Injury may occur to sugarcane under moisture stress. Maximum annual rate is 17.2 pt or 9.6 lb of formulated atrazine product per acre (equivalent to 8.6 lb ai per A of atrazine). No mixing/loading within 50 ft of canals. Restricted Use Pesticide.

Asulox or

Asulam

(several)

(6 – 8 pt)

Asulam

(2.5 – 3.34 lb)

For control of alexandergrass, foxtail, goosegrass, broadleaf panicum, and other annual grasses but response is slow. Apply to actively growing grass weeds and when sugarcane is at least 18 inches in height. Application may be broadcasted, directed, or semi-directed. Do not tank mix.

Dicamba2 (several)

(1 – 1.5 pt)

Dicamba

(0.25 – 0.75 lb)

For control of many annual, biennial, and perennial broadleaf weeds. Use high rates for large or difficult-to-control weeds and for difficult perennials 2-4 pt (at 2-4 pt per application injury to sugarcane is likely to occur). Re-treat as needed, but do not exceed 4 pt per acre per growing season. Take care to prevent spray drift to sensitive crops, and consult the Florida Organo-Auxin herbicide rule prior to application.

Envoke - Plant Cane

(0.3 – 0.6 oz)

Trifloxysulfuron-sodium

(0.23 – 0.45 lb)

Provides good control of alligatorweed, broadleaf panicum, itchgrass, spiny amaranth, yellow and purple nutsedge, and several other grass and broadleaf weeds. Apply to weed seedlings less than 4 to 6 inches in height. Applications can only be POST-directed or POST over-the-top. May be tank mixed with Evik or Atrazine. However, reduction in weed control can occur when mixed with these herbicides. Apply with NIS at 0.25% v/v, and COC at 0.5 to 1.0% v/v may be used ONLY when applying post-directed.

Envoke - Ratoon Cane

(0.3 – 0.6 oz)

Trifloxysulfuron-sodium

(0.23 – 0.45 lb)

Weed spectrum controlled will be the same as for Envoke in plant cane. Apply POST over-the-top or post-directed. POST over-the-top may be applied until sugarcane reaches 24” in height. The 0.6 oz rate may be applied POST-directed to cane that is >18” tall through layby.

Envoke - Plant Cane

(0.6 oz)

+

Asulox

(4 pt)

Trifloxysulfuron-sodium

(0.23 lb)

+

Asulam

(1.65 lb)

Apply post-directed to sugarcane that is 18" tall through layby. Best for seedling weeds less than 4-6" in height. This tank-mixture controls a broader spectrum of grass and broadleaf species than Envoke or Asulam applied alone, and provides better control of larger grasses. Provides good control of yellow and purple nutsedge, spiny pigweed, alligatorweed, broadleaf panicum, fall panicum, goosegrass, itchgrass, and several other grass and broadleaf species. Preliminary results suggest that 2,4-D tank-mixtures may also reduce grass control, particularly when higher rates of 2,4-D are used. Apply with non-ionic surfactant at a rate of 0.25% v/v.

Envoke - Ratoon Cane

(0.3 - 0.6 oz)

+

Asulox

(4 pt)

Trifloxysulfuron-sodium

(0.23 lb)

+

Asulam

(1.65 lb)

Will control a broader spectrum of grass and broadleaf weed species than Envoke or Asulox applied alone. Apply 0.3 oz Envoke POST over-the-top of sugarcane that is up to 24 inches in height tall. Apply 0.6 oz Envoke POST-directed in sugarcane that is up to 18 inches in height through layby. Apply with NIS at 0.25 % v/v.

Evik

(0.5 – 1.5 lb)

Ametryn

(0.38 – 1.14 lb)

POST-directed to the base of plant or ratoon cane to emerged weeds up to 3 inches in height. For mixed weed infestations use 1.5 lb Evik + 0.5 qt 2,4-D amine to improve weed control. Activity can be increased by adding 0.5% v/v of surfactant to the spray. Repeat application after 30 days prior to close-in if needed. Avoid wetting cane foliage, or injury may occur.

Glyphosate

(several)

(4 – 5 qt)

Glyphosate

(4 – 5 lb)

For control of emerged annual and perennial weeds when sugarcane is at least 3 feet in height. May be applied using hooded or shielded sprayers for weed control between the rows of sugarcane. Contact with the sugarcane foliage will cause injury. Consult the label for specific rates of application for various weeds and low rate technology application.

Sandea

(0.75 – 1.33 oz)

Halosulfuron-methyl

(0.032 – 0.063 lb)

May be applied POST to any stage of sugarcane growth primarily for control of yellow and purple nutsedge. Also controls some broadleaf weed species. No more than 3 applications (including pre-plant applications) may be made with the total use rate not to exceed 2 2/3 oz of product by weight (0.15 lb ai) per acre per year. Apply to emerged nutsedge after nutsedge has reached 3 to 8 leaf stage. Apply by ground equipment at 10 or more gallons of water per acre. Add COC at 1% v/v or NIS 0.25 to 0.50% v/v. Applications should be made to actively growing weeds.

Yukon

(4 – 8 oz)

Halosulfuron-methyl

(0.032 – 0.063 lb)

+

Dicamba

(0.125 – 0.25 lb)

May be applied POST to any stage of sugarcane growth primarily for control of yellow and purple nutsedge. Apply to emerged nutsedge after sedge has reached 3 to 8 leaf stage. Do not make more than 2 applications per growing season with the total amount per acre not to exceed 8 oz of product by weight. Take care to prevent spray drift to sensitive crops, and consult the Florida Organo-Auxin herbicide rule prior to application. Add COC at 1% v/v or NIS at 0.25-0.50% v/v. Applications should be made to actively growing weeds.

1 WARNING: The following information has been added to the atrazine and metribuzin labels. This statement should be heeded by all prospective users and steps should be taken to comply with this label change:

"Atrazine and metribuzin are chemicals which can travel (seep or leach) through soil and can contaminate groundwater as a result of agricultural use. Atrazine and metribuzin have been found in groundwater as a result of agricultural use. Users are advised not to apply atrazine or metribuzin where the water table (groundwater) is close to the surface and where the soils are very permeable, i.e., well-drained soils such as sands and loamy sands. Your local agricultural agencies can provide further information on the type of soil in your area and location of groundwater. In addition, some product label statements include as a further qualification of risky soils, soils containing sinkholes over limestone bedrock, severely fractured surfaces, and substrates which would allow direct introduction into an aquifer."

2 See fact sheet SS-AGR-12 Florida's Organo-Auxin Herbicide Rule for state rules pertaining to application of organo-auxin herbicides in Florida.

Footnotes

1.

This document is SS-AGR-09, one of a series of the Agronomy Department, UF/IFAS Extension. Revised November 2010. Reviewed January 2014. This publication is also a part of the Sugarcane Handbook, an electronic publication of the Agronomy Department. For more information, contact the editor of the Sugarcane Handbook, Ronald W. Rice (rwr@ufl.edu). Please visit the EDIS website at http://edis.ifas.ufl.edu.

2.

D. C. Odero, assistant professor, Agronomy Department, Everglades Research and Education Center - Belle Glade, FL; and J. A. Dusky, professor and assistant dean for Extension; UF/IFAS Extension, Gainesville, FL 32611.

The use of trade names in this publication is solely for the purpose of providing specific information. UF/IFAS does not guarantee or warranty the products named, and references to them in this publication does not signify our approval to the exclusion of other products of suitable composition.

Use herbicides safely. Read and follow directions on the manufacturer's label.


The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.