Weed Management in Sugarcane 1

Transcription

1 SS-AGR-09 1 D. C. Odero and J. A. Dusky 2 Successful weed control is essential f economical sugarcane production in Flida. Weeds can reduce sugarcane yields by competing f moisture, nutrients, and light during the growing season. Several weed species also serve as alternate hosts f disease and insect pests. Weed control is most critical early in the season pri 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 Figure 1. Sugarcane crops being cleared of weeds. Credits: Thomas Wright, UF/IFAS. produce seed will multiply weed control problems by being a source of seed bank replenishment and re-infestation in subsequent years. See Table 1 f available herbicidal options. 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. Crop Competition Crop competition f sunlight is one of the most imptant concepts to be utilized in effective weed control. A good stand of sugarcane that emerges rapidly and unifmly and 1. This document is SS-AGR-09, one of a series of the Agronomy Department, UF/IFAS Extension. Revised November Reviewed January This publication is also a part of the Sugarcane Handbook, an electronic publication of the Agronomy Department. F me infmation, contact the edit of the Sugarcane Handbook, Ronald W. Rice (rwr@ufl.edu). Please visit the EDIS website at 2. D. C. Odero, assistant profess, Agronomy Department, Everglades Research and Education Center - Belle Glade, FL; and J. A. Dusky, profess and assistant dean f Extension; UF/IFAS Extension, Gainesville, FL The use of trade names in this publication is solely f the purpose of providing specific infmation. UF/IFAS does not guarantee 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 Opptunity Institution authized to provide research, educational infmation and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, col, religion, age, disability, sex, sexual ientation, marital status, national igin, political opinions affiliations. U.S. Department of Agriculture, Cooperative Extension Service, University of Flida, IFAS, Flida A&M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, Dean

2 Figure 2. Sugarcane field in Immokalee, Flida. Credits: Josh Wickham, UF/IFAS. fms 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, harvest damage will create open spaces in the sugarcane canopy in which weeds can proliferate. A concentrated efft to maintain maximum sugarcane populations throughout all phases of production will benefit weed control effts. Cultivation Cultivation can be an economical means of suppressing weed growth. To ensure that the sugarcane plants get the early advantage in the competition f 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 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 cultivats must be able to cut through surface debris and thoughly mix the soil. be effective if the sugarcane is taller than the competing weeds. Accurate herbicide placement is crucial f banded directed applications. High application speeds and rough fields can result in po application unifmity, particularly with banded applications. Speed must be limited if movement of the boom drop nozzles results in excessive amounts of herbicide actually depositing in the untreated strip. Broadcast applications are generally less affected by these facts, since nozzle overlap helps ensure unifmity of herbicide placement. Proper timing of herbicide application with respect to the growth stage of the weeds is extremely critical. Nmally, weeds should be treated when they are 4 to 8 in height. Read the label f the proper time of application of each herbicide. The herbicides suggested in this publication are those that have perfmed well in IFAS research. Herbicide users must read the label and follow all instructions and precautions carefully. Accurate calibration of application equipment is extremely imptant in providing effective weed control. The effectiveness and economic usefulness of herbicides must be evaluated by each grower f his particular situation. Initial use of these chemicals should be restricted to a limited acreage f familiarization. You are responsible f the perfmance of the chemicals you use. Herbicides, like any pesticide, should be handled with care. Ste herbicides behind locked dos in the iginal containers with the label intact and separated from seed, fertilizers, and other pesticides. Herbicides Herbicides can be useful and economical tools in sugarcane production. They must be incpated into an overall management plan to obtain their maximum benefit. It is imptant 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 semi-directed postemergence (POST) herbicide applications can generally only 2

3 Table 1. Weed management in sugarcane. Trade Name & Broadcast ( qt) Aatrex 4L Atrazine 4L (4 8 pt) Aatrex Nine-O Atrazine 90DF ( lb) K-4 (4 lb) Prowl 3.3 EC ( qt) Pendimethalin 3.3 ( qt) Senc Metribuzin ( lb) (4 5 lb) Atrazine 1 Hexazinone Diuron ( lb) Pendimethalin Pendimethalin (2 3 lb) Metribuzin ( lb) FALLOW LAND MANAGEMENT MUCK AND SANDY SOILS F control of emerged annual and perennial weeds growing in and around sugarcane 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 me days after application befe tillage. Repeat applications may be made up to a maximum of lb ai per acre per year. Apply in 10 to 40 gal of water per acre. Consult the label f specific rates of application f various weeds and low rate technology application. PREEMERGENCE-PLANT CANE MUCK SOILS F control of annual broadleaf and some grass weeds. Broadcast by ground equipment befe sugarcane emerges at time of planting ratooning. Maximum annual rate is 20 pt 11.1 lb of fmulated 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. F control of annual grass and broadleaf weeds. Application should be made immediately following planting and row packing, but pri to crop and weed emergence. F best weed control, application should be made to firm, well prepared seedbed free from excess clods plant residue. When applying K-4 alone in combination with other diuron containing products, do not exceed 6 lb of diuron per acre. Do not apply me than 7.5 lb per acre per year of K-4 and do not apply K-4 within 234 days of harvest. F control of most annual grasses and broadleaf weeds. Broadcast band by ground equipment. Apply at time of planting ratooning, but pri to emergence. Mechanical incpation rainfall within 7 days of application is needed to incpate pendimethalin applied alone in combination with metribuzin into the soil, activity will be significantly decreased. Do not exceed 14.4 pt (equivalent to 5.95 lb ai per acre) of pendimethalin 2.33 lb (equivalent to 1.75 lb ai per acre) of metribuzin per acre in one growing season. 3

4 Aatrex 4L Atrazine 4L (4 8 pt) ( lb) Senc Metribuzin Atrazine Metribuzin ( lb) F control of most broadleaf and certain grass weeds. Broadcast band by ground equipment. Apply at time of planting ratooning, but pri to weed emergence. Rainfall within 7 days of application is needed to incpate the herbicide into the soil, activity will be significantly decreased. Do not exceed 20 pt 11.1 lb of fmulated atrazine product per acre (equivalent to10 lb ai per acre of atrazine) 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. ( lb) Callisto ( fl oz) Aatrex 4L Atrazine 4L (4 8 pt) ( lb) F 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 a nonionic surfactant (NIS) at 0.25% v/v to the spray solution. UAN at 2.5% v/v ammonium sulfate (AMS) at 8.5 lb per 100 gal of spray solution can also be added. Refer to label f tank mix partners. Do not apply me than 7.7 fl oz (0.24 lb ai) per acre as a PRE application. Do not make me than two applications per year. Two applications should not be made less than 14 days apart. PREEMERGENCE-PLANT CANE SANDY SOILS Atrazine 1 F control of annual broadleaf and some grass weeds. Broadleaf weed control will be superi to annual grass weed control. Broadcast by ground equipment befe sugarcane emerges. Good soil moisture light rainfall is essential f improved efficacy. May be used in split application: 4 pt 2.2 lb of fmulated atrazine product (2.0 lb ai) per acre PRE followed by 4 pt 2.2 lb of fmulated 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 9.6 lb of fmulated 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. Aatrex Nine-O Atrazine 90DF ( lb) 4

5 Direx 4L Diuron 4L ( qt) Karmex DF Diuron 80/Diuron DF Diuron ( lb) F control of broadleaf and grass weeds. Controls broadleaf better than grass weeds. Broadcast pri to weed emergence. An additional POST spray of 1.6 lb per acre may be applied to prolong weed control. Do not apply me than 6 lb 4.8 qt of fmulated diuron product per acre (equivalent to 4.8 lb ai per acre of diuron) between planting (ratooning) and harvest. Callisto ( fl oz) ( qt) Prowl 3.3 EC ( qt) Pendimethalin 3.3 ( lb) F 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 a nonionic surfactant (NIS) at 0.25% v/v to the spray solution. UAN at 2.5% v/v ammonium sulfate (AMS) at 8.5 lb per 100 gal of spray solution can also be added. Refer to label f tank mix partners. Do not apply me than 7.7 fl oz (0.24 lb ai) per acre as a PRE application. Do not make me than two applications per year. Two applications should not be made less than 14 days apart. MUCK AND SANDY SOILS F control of emerged annual and perennial weeds growing in and around sugarcane fields pri to sugarcane emergence. Higher rates are to be used f difficult to (4 5 lb) control weeds. F specific rates of application and instructions f control of various weeds, consult the label. F infmation concerning low rate technology applications, consult the label. Pendimethalin F control of most annual grasses and certain broadleaf weeds. Apply at time of planting ratooning, but befe weeds emerge. Broadcast band by ground (2-4 lb) equipment. May be applied by air. Must be incpated thoughly and unifmly either by mechanical incpation 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. ( qt) Prowl H 2 O ( qt) Val SX (6 8 oz) Pendimethalin Flumioxazin ( lb) A microencapsulated fmulation of pendimethalin with no od, reduced staining, and lower use rate than other pendimethalins. Apply at planting befe weeds emerge. Weed control is equal to that of Prowl 3.3 fmulation. Do not exceed 12.5 pt (equivalent to 5.95 ai lb per acre) of Prowl H 2 0 in one growing season. F control grass and broadleaf weeds. May be applied 2 weeks pri to planting and befe sugarcane emerges. May be used to assist in POST burndown. Control will be improved with the addition of 1.25% v/v COC methylated seed oil (MSO) 0.25% v/v of NIS. Residual activity is reduced when applied to soils with me than 10% ganic matter. Refer to the supplemental label f sugarcane f me infmation. Do not apply me than 8 oz per acre per application (equivalent to lb ai per acre). Do not apply me than 12 oz per acre per growing season (equivalent to lb ai per acre). Do not apply within 90 days of harvest. Refer to the supplemental label f sugarcane f me specific infmation. PREEMERGENCE-RATOON CANE MUCK AND SANDY SOIL After fertilization, cultivate row middles and then apply selected herbicide listed above f plant cane crops. Apply befe 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. 5

6 K-4 (4 lb) Senc DF ( lb) 2,4-D Amine 2 2,4-D Amine Dicamba 2 (2-6 pts) Aatrex 4L Atrazine 4L (4 8 pt) Hexazinone diuron ( lb) metribuzin 1 ( lb) 2,4-D ( lb) 2,4-D Dicamba ( lb) Atrazine 1 ( lb) PREEMERGENCE-RATOON CANE - MUCK SOIL F control of annual and broadleaf weeds. Applications should be made immediately following harvest pri to subsequent weed germination. Excess plant residue on the soil surface may decrease the effectiveness of K-4 and should be removed minimized. May be applied POST to stubble sugarcane until the crop reaches a height of 18 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 f 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 1% v/v of COC is recommended. If a tank-mix partner is being used, follow the most restrictive adjuvant recommendation. POSTEMERGENCE MUCK SOILS F control of pigweeds, butterweed, cudweed, common purslane, goosegrass, and broadleaf panicum. Should be used as directed spray befe 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 F control of many broadleaf weeds including spiny amaranth, ragweed, and mninggly. Use high rates f large difficult-to-control weeds, such as alligatweed. 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 Flida Organo-Auxin herbicide rule pri to application. F control of many annual, biannual, and perennial broadleaf weeds. Apply anytime after weed emergence but pri 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 f control of annual weeds, and up to 6 pt per acre may be used f 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 Flida Organo-Auxin herbicide rule pri to application. Semi-directed spray preferred when weeds are have less than 3 expanded leaves (befe exceeding 1.5 inches in height). With good soil moisture 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 9.6 lb of fmulated 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. Aatrex Nine-O Atrazine 90DF ( lb) 6

7 Asulox Asulam (6 8 pt) Dicamba 2 (1 1.5 pt) Envoke - Plant Cane ( oz) Envoke - Ratoon Cane ( oz) Envoke - Plant Cane (0.6 oz) Asulox (4 pt) Envoke - Ratoon Cane ( oz) Asulox (4 pt) Evik ( lb) (4 5 qt) Asulam ( lb) Dicamba ( lb) Trifloxysulfuron-sodium ( lb) Trifloxysulfuron-sodium ( lb) Trifloxysulfuron-sodium (0.23 lb) Asulam (1.65 lb) Trifloxysulfuron-sodium (0.23 lb) Asulam (1.65 lb) Ametryn ( lb) (4 5 lb) F 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, semi-directed. Do not tank mix. F control of many annual, biennial, and perennial broadleaf weeds. Use high rates f large difficult-to-control weeds and f 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 Flida Organo-Auxin herbicide rule pri to application. Provides good control of alligatweed, 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 POSTdirected POST over-the-top. May be tank mixed with Evik 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 postdirected. Weed spectrum controlled will be the same as f Envoke in plant cane. Apply POST over-the-top 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. Apply post-directed to sugarcane that is 18 tall through layby. Best f seedling weeds less than 4-6 in height. This tank-mixture controls a broader spectrum of grass and broadleaf species than Envoke Asulam applied alone, and provides better control of larger grasses. Provides good control of yellow and purple nutsedge, spiny pigweed, alligatweed, 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. Will control a broader spectrum of grass and broadleaf weed species than Envoke 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. POST-directed to the base of plant ratoon cane to emerged weeds up to 3 inches in height. F 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 pri to close-in if needed. Avoid wetting cane foliage, injury may occur. F control of emerged annual and perennial weeds when sugarcane is at least 3 feet in height. May be applied using hooded shielded sprayers f weed control between the rows of sugarcane. Contact with the sugarcane foliage will cause injury. Consult the label f specific rates of application f various weeds and low rate technology application. 7

8 Sandea ( oz) Yukon (4 8 oz) Halosulfuron-methyl ( lb) Halosulfuron-methyl ( lb) Dicamba May be applied POST to any stage of sugarcane growth primarily f control of yellow and purple nutsedge. Also controls some broadleaf weed species. No me 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 me gallons of water per acre. Add COC at 1% v/v NIS 0.25 to 0.50% v/v. Applications should be made to actively growing weeds. May be applied POST to any stage of sugarcane growth primarily f control of yellow and purple nutsedge. Apply to emerged nutsedge after sedge has reached 3 to 8 leaf stage. Do not make me 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 Flida Organo-Auxin herbicide rule pri to application. Add COC at 1% v/v NIS at % v/v. Applications should be made to actively growing weeds. ( lb) 1 WARNING: The following infmation 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 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 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 infmation 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 Flida s Organo-Auxin Herbicide Rule f state rules pertaining to application of gano-auxin herbicides in Flida. 8