\m 28 10 3 2 1 'Successful Weed Control in Peanuts' \m 83 35 4 3 1 'Preplant Weed Control' \m 128 53 22 4 1 'Weed Control in the Cracking Stage' \m 191 79 123 5 1 'Postemergence Weed Control' \m 244 99 103 6 1 'Effectiveness of Herbicides on Specific Weeds' \m 245 100 29 6 2 'Bristly Starbur' \m 277 113 3 6 2 'Cocklebur' \m 303 123 118 7 2 'Florida Beggarweed' \m 327 134 57 7 2 'Florida Pusley' \m 352 144 98 8 2 'Morningglory' \m 377 155 88 8 2 'Pigweed' \m 402 165 116 9 2 'Sicklepod (coffeeweed)' \m 428 177 86 9 2 'Crabgrass' \m 453 187 125 10 2 'Goosegrass' \m 477 198 38 10 2 'Johnsongrass (from seed)' \m 502 208 94 11 2 'Sandbur' \m 526 218 116 11 2 'Texas Panicum' \m 552 229 114 12 2 'Junglerice' \m 576 240 24 12 2 'Signalgrass' \m 601 250 64 13 2 'Purple Nutsedge' \m 625 261 2 13 2 'Yellow Nutsedge' \t'January 1988' 'VIII-'page \a Danny Colvin, Extension Weed Specialist \a \a WEED CONTROL IN PEANUTS Danny Colvin, Extension Weed Specialist \h 1 'Successful Weed Control in Peanuts' WEED CONTROL IN PEANUTS Successful Weed Control in Peanuts Successful weed control in peanuts involves using good managemnt practices in all phases of peanut production. Weeds compete with peanuts for moisture, nutrients, and light and the greatest competition usually occurs during the first six weeks after planting. Although late-season weeds may not be as competitive as early-season weeds, they may interfere with harvesting and also with fungicide and insecticide applications. CROP ROTATIONS are an important part of the peanut weed control program. Certain broadleaf weeds, which are not easily controlled in peanuts, may be controlled by herbicides which can be used in a preceding crop such as corn. Other benefits of crop rotations may include reduction in insect, disease and nematode problems. HERBICIDES are the most effective method for controlling weeds in peanuts. Before purchasing a herbicide you should first know your weed problem, since many herbicides are most effective on certain weeds. Once your weed problem has been determined, the section entitled "Effectiveness of Herbicides on Specific Weeds" can be helpful in determining which herbicide is best for your weed problem. The most effective weed control and highest peanut yields have generally been obtained using a herbicide program consisting of a preplant incorporated treatment, followed by a cracking stage treatment, followed by a postemergence treatment. The cracking stage treatment, if properly timed, is generally the most critical application in the peanut weed control program. Maximum effectiveness will be achieved if application is timed to the emergence of the weeds and not the peanuts. If weeds have not emerged at time of peanut cracking, delay application. The herbicides listed in this section have consistently performed well in IFAS ressearch. CAUTION: It should be noted that 1) peanuts under stress from cold weather, thrip injury, etc. may be subject to more injury from improperly timed cracking stage applications and 2) essentially all herbicide research in Florida has been conducted on the variety "Florunner" and tolerance of other varieties has not been determined. CULTIVATION can be utilized if effective weed control is not achieved with herbicides. However, if weeds have been controlled with herbicides, there is generally little benefit from cultivation. If cultivation is needed, avoid throwing soil on the peanut vines. Soil thrown on the vines may result in increased incidence of stem rot (white mold). All label instructions and precautions should be followed carefully, since rates higher than needed may injure the crop and lower rates may not provide acceptable weed control. Be sure that application is properly timed in relation to the stage of growth of the crop and weeds. Do not allow spray to drift to cotton, tobacco or other sensitive crops. Store herbicides behind locked doors, in the original container, with the label intact, and separated from seed, fertilizer and other pesticides. \b\v \h 1 'Preplant Weed Control' \v \v \v Preplant Weed Control ------------------------------------------------------------------------------- Trade Name and Broadcast Rate/Acre Common Name and Broadcast Rate/Acre of Commercial Product of Active Ingredient ------------------------------------------------------------------------------- Balan (3-4 qts) benefin (1.13-1.5 lbs) or or Prowl (0.75-1.0 qt) pendimethalin (0.75-1 lb) REMARKS: Annual grasses and also hard-to-control grasses such as sandbur and Texas panicum. Good control of Florida pusley and pigweed. Refer to the label for proper incorporation procedures. May be applied by injection into center-pivot irrigation systems. Lasso (2-3 qts) alachlor (2-3 lbs) or or Dual (2-3 pts) metolachlor (2-3 lbs) REMARKS: Lasso may be applied preplant incorporated and will aid in the control of yellow nutsedge and Florida beggarweed. If 3 qts are applied preplant incorporated, care should be taken to apply no more than 2 qts at cracking so as not to exceed the maximum allowable alachlor levels on peanuts. Dual may be applied preplant incorporated and will give good control of yellow nutsedge. If yellow nutsedge is anticipated as a problem and cool wet soil conditions exist, Dual has shown less injury to peanuts than has Vernam. Keep in mind Dual will only control yellow nutsedge. If Dual is applied preplant incorporated do not exceed 6 lbs/A in additive after-cracking applications. Vernam 7E (2.3-2.9 pt) vernolate (2.0-2.5 lbs) REMARKS: Suppresses nutsedge. Controls certain annual grasses, Florida pusley and pigweed. Apply within 10 days of planting. Incorporate into the soil to a depth of 3 inches IMMEDIATELY AFTER APPLICATION. If possible, combine application and incorporation in the same operation. May be applied by injection into center-pivot irrigation systems. ------------------------------------------------------------------------------- \b\v \h 1 'Weed Control in the Cracking Stage' \v \v \v Cracking Stage NOTE: Due to the suspension of dinoseb and dinoseb-containing compounds by the EPA, successful at-cracking-stage weed control treatments in peanuts may be difficult. As of this writing, both Gramoxone Super and Cobra herbicide registration packages have beem submitted to the EPA for consideration and labeling in peanuts. In the event neither of these compounds is granted full federal registration, the Florida Cooperative Extension Service will petition EPA for a Section 18 Emergency Exemption for a suitable contact herbicide to be used in peanuts. Your local County Extension Agent will be able to provide you with this information as soon as it is available. ------------------------------------------------------------------------------- Trade Name and Broadcast Rate/Acre Common Name and Broadcast Rate/Acre of Commercial Product of Active Ingredient ------------------------------------------------------------------------------- Amiben (1-1.5 gal) chloramben (2.0-3.0 lbs) + Crop Oil Conc. (2 pts) REMARKS: Excellent control of Florida beggarweed with little control of most other troublesome broadleaf weeds in peanuts. Precautions should be taken not to apply Amiben + Crop Oil past the cracking stage as a potential exists for herbicide metabolites to be transferred into the forming nuts. Blazer (1.5-2.0 pts) acifluorfen (0.38-0.50 lbs) REMARKS: Minimal crop injury and best weed control will be attained when Blazer is applied at true ground cracking of peanuts when weeds are present. Blazer is most active on morningglories, pigweed, cocklebur and other seedling broadleaf weeds. Blazer (1.5-2.0 pts) acifluorfen (0.38-0.50 lbs) + + Amiben (1-1.5 gal) chloramben (2.0-3.0 lbs) or Lasso (3.0-4.0 pts) or alachlor (1.5-2.0 lbs) or Dual (1.5-2.0 pts) or metolachlor (1.5-2.0 lbs) REMARKS: Addition of any of these compounds will help provide additional weed control not offered by Blazer alone. The addition of Amiben will enhance Florida beggarweed control while Lasso or Dual additions will increase residual grass control as well as assist in small-seeded broadleaf weed control. The University of Florida has not conducted enough studies with Blazer tank mixes applied at cracking to predict the eventual severity of any crop injury that may result. Lasso (2-3 qts) alachlor (2-3 lbs) or Dual (2-3 pts) or metolachlor (2-3 lbs) REMARKS: Both compounds give good grass and small-seeded broadleaf control. However, neither compound will be active on existing weeds which have already germinated. Lasso will give better control of sicklepod and Florida beggarweed. Best results will be attained when either compound is mixed with an approved contact herbicide. Stay in contact with your County Extension Agent for information concerning Emergency Exemption contact herbicide for use on peanuts. ------------------------------------------------------------------------------- \b\v \h 1 'Postemergence Weed Control' \v \v \v Postemergence Weed Control ------------------------------------------------------------------------------- Trade Name and Broadcast Rate/Acre Common Name and Broadcast Rate/Acre of Commercial Product of Active Ingredient ------------------------------------------------------------------------------- Basagran (0.75-1.5 qt) bentazon (0.75-1.5 lb) REMARKS: Good control of cocklebur, bristly starbur, and yellow nutsedge. Rate depends on weed species and size; therefore, refer to the label. Good spray coverage is essential for control. Do not apply to peanuts which have been subjected to stress. Blazer 2L (1.5-2.0 pt) acifluorfen (0.375-0.5 lbs) REMARKS: Good control of many broadleaf weed species including hairy indigo, crotalaria and citron. Rate depends on size of weeds and species, therefore, refer to the label. Good spray coverage is essential for control. Add a surfactant at the rate suggested on the label. Do not apply when weeds or peanuts are stressed. Do not apply within 75 days of harvest. Sprayed leaves and stems may be crinkled or burned but new leaves will appear normal. Butyrac (1.0 pt) 2,4-DB (0.25 lbs) or Butoxone (1.2 pt) REMARKS: Controls morningglory and cocklebur. Poor control of Florida beggarweed. Apply 2 to 12 weeks after planting. A second application may be made 3 weeks later. Do not apply to drought stressed peanuts. Dual (Layby) (1.5 - 2.0 pts) metolachlor (1.5-2.0 lbs) REMARKS: Use only when late germinating weeds are expected to be a problem. Applications must be made before weeds are present for best results. Do not exceed 6 pts/acre per season. Poast (1.0-2.5 pts) sethoxydim (0.19-0.47 lbs) + Crop Oil Conc. (2 pts) REMARKS: Good control of many grass weed species including crabgrass, goosegrass, Texas panicum, and bermudagrass. Split applications may be required for certain hard-to-control grasses but no more than 2.5 pts may be applied per acre/growing season. Best results will be obtained when applied in 15-20 GPA carrier volume. ALL applications should include a crop oil concentrate at 2 pts per acre. ------------------------------------------------------------------------------- \b\v \h 1 'Effectiveness of Herbicides on Specific Weeds' \h 2 'Bristly Starbur' \v \v \v Estimated Effectiveness of Herbicides on Specific Weeds \pEstimated effectiveness based on rates recommended in this guide. \pEffectiveness may vary depending on factors such as herbicide rate, size of \pweeds, time of application, soil and weather. BRISTLY STARBUR: ------------------------------------------------------------------------------- Herbicide Time of Application Estimated Effectiveness ------------------------------------------------------------------------------- Balan or Prowl Preplant incorporated Less than 60% control Vernam Preplant incorporated Less than 60% control Lasso or Dual At cracking stage 60 - 80% control Amiben At cracking stage Less than 60% control Blazer At cracking stage, post- Less than 60% control emergence over the top to 80% control Butyrac or Butoxone Postemergence over Less than 60% control the top Basagran Postemergence over 90 - 100% control the top Poast Postemergence over Less than 60% control the top ------------------------------------------------------------------------------- \v*Estimated effectiveness based on rates recommended in this guide. \vEffectiveness may vary depending on factors such as herbicide rate, size of \vweeds, time of application, soil and weather. \h 2 'Cocklebur' COCKLEBUR: ------------------------------------------------------------------------------- Herbicide Time of Application Estimated Effectiveness ------------------------------------------------------------------------------- Balan or Prowl Preplant incorporated Less than 60% control Vernam Preplant incorporated Less than 60% control to 80% control Lasso or Dual At cracking stage 60 - 90% control Amiben At cracking stage Less than 60% control Blazer At cracking stage, post- 80 - 100% control emergence over the top Butyrac or Butoxone Postemergence over 90 - 100% control the top Basagran Postemergence over 90 - 100% control the top Poast Postemergence over Less than 60% control the top ------------------------------------------------------------------------------- \v*Estimated effectiveness based on rates recommended in this guide. \vEffectiveness may vary depending on factors such as herbicide rate, size of \vweeds, time of application, soil and weather. \b \h 2 'Florida Beggarweed' \v \v FLORIDA BEGGARWEED: ------------------------------------------------------------------------------- Herbicide Time of Application Estimated Effectiveness ------------------------------------------------------------------------------- Balan or Prowl Preplant incorporated Less than 60% control Vernam Preplant incorporated Less than 60% control Lasso or Dual At cracking stage 80 - 90% control Amiben At cracking stage 80 - 90% control Blazer At cracking stage, post- Less than 60% control emergence over the top Butyrac or Butoxone Postemergence over Less than 60% control the top Basagran Postemergence over Less than 60% control the top Poast Postemergence over Less than 60% control the top ------------------------------------------------------------------------------- \v*Estimated effectiveness based on rates recommended in this guide. \vEffectiveness may vary depending on factors such as herbicide rate, size of \vweeds, time of application, soil and weather. \h 2 'Florida Pusley' FLORIDA PUSLEY: ------------------------------------------------------------------------------- Herbicide Time of Application Estimated Effectiveness ------------------------------------------------------------------------------- Balan or Prowl Preplant incorporated 90 - 100% control Vernam Preplant incorporated 80 - 90% control Lasso or Dual At cracking stage 80 - 90% control Amiben At cracking stage Less than 60% control Blazer At cracking stage, post- 90 - 100% control emergence over the top Butyrac or Butoxone Postemergence over 60 - 80% control the top Basagran Postemergence over 60 - 80% control the top Poast Postemergence over Less than 60% control the top ------------------------------------------------------------------------------- \v*Estimated effectiveness based on rates recommended in this guide. \vEffectiveness may vary depending on factors such as herbicide rate, size of \vweeds, time of application, soil and weather. \b \h 2 'Morningglory' \v \v MORNINGGLORY: ------------------------------------------------------------------------------- Herbicide Time of Application Estimated Effectiveness ------------------------------------------------------------------------------- Balan or Prowl Preplant incorporated Less than 60% control Vernam Preplant incorporated 80 - 90% control Lasso or Dual At cracking stage Less than 60% control to 80% control Amiben At cracking stage Less than 60% control Blazer At cracking stage, post- 90 - 100% control emergence over the top Butyrac or Butoxone Postemergence over 80 - 90% control the top Basagran Postemergence over 60 - 90% control the top Poast Postemergence over Less than 60% control the top ------------------------------------------------------------------------------- \v*Estimated effectiveness based on rates recommended in this guide. \vEffectiveness may vary depending on factors such as herbicide rate, size of \vweeds, time of application, soil and weather. \h 2 'Pigweed' PIGWEED: ------------------------------------------------------------------------------- Herbicide Time of Application Estimated Effectiveness ------------------------------------------------------------------------------- Balan or Prowl Preplant incorporated 90 - 100% control Vernam Preplant incorporated 80 - 90% control Lasso or Dual At cracking stage 90 - 100% control Amiben At cracking stage Less than 60% control Blazer At cracking stage, post- 90 - 100% control emergence over the top Butyrac or Butoxone Postemergence over 80 - 90% control the top Basagran Postemergence over 80 - 90% control the top Poast Postemergence over Less than 60% control the top ------------------------------------------------------------------------------- \v*Estimated effectiveness based on rates recommended in this guide. \vEffectiveness may vary depending on factors such as herbicide rate, size of \vweeds, time of application, soil and weather. \b \h 2 'Sicklepod (coffeeweed)' \v \v SICKLEPOD (COFFEEWEED): ------------------------------------------------------------------------------- Herbicide Time of Application Estimated Effectiveness ------------------------------------------------------------------------------- Balan or Prowl Preplant incorporated Less than 60% control Vernam Preplant incorporated Less than 60% control to 80% control Lasso or Dual At cracking stage Less than 60% control to 80% control Amiben At cracking stage Less than 60% control Blazer At cracking stage, post- Less than 60% control emergence over the top Butyrac or Butoxone Postemergence over 60 - 80% control the top Basagran Postemergence over Less than 60% control the top Poast Postemergence over Less than 60% control the top ------------------------------------------------------------------------------- \v*Estimated effectiveness based on rates recommended in this guide. \vEffectiveness may vary depending on factors such as herbicide rate, size of \vweeds, time of application, soil and weather. \h 2 'Crabgrass' CRABGRASS: ------------------------------------------------------------------------------- Herbicide Time of Application Estimated Effectiveness ------------------------------------------------------------------------------- Balan or Prowl Preplant incorporated 90 - 100% control Vernam Preplant incorporated 90 - 100% control Lasso or Dual At cracking stage 90 - 100% control Amiben At cracking stage 80 - 100% control Blazer At cracking stage, post- Less than 60% control emergence over the top Butyrac or Butoxone Postemergence over Less than 60% control the top Basagran Postemergence over Less than 60% control the top Poast Postemergence over 80 - 100% control the top ------------------------------------------------------------------------------- \v*Estimated effectiveness based on rates recommended in this guide. \vEffectiveness may vary depending on factors such as herbicide rate, size of \vweeds, time of application, soil and weather. \b \h 2 'Goosegrass' \v \v GOOSEGRASS: ------------------------------------------------------------------------------- Herbicide Time of Application Estimated Effectiveness ------------------------------------------------------------------------------- Balan or Prowl Preplant incorporated 90 - 100% control Vernam Preplant incorporated 90 - 100% control Lasso or Dual At cracking stage 90 - 100% control Amiben At cracking stage 80 - 100% control Blazer At cracking stage, post- Less than 60% control emergence over the top Butyrac or Butoxone Postemergence over Less than 60% control the top Basagran Postemergence over Less than 60% control the top Poast Postemergence over 80 - 100% control the top ------------------------------------------------------------------------------- \v*Estimated effectiveness based on rates recommended in this guide. \vEffectiveness may vary depending on factors such as herbicide rate, size of \vweeds, time of application, soil and weather. \h 2 'Johnsongrass (from seed)' JOHNSONGRASS (FROM SEED): ------------------------------------------------------------------------------- Herbicide Time of Application Estimated Effectiveness ------------------------------------------------------------------------------- Balan or Prowl Preplant incorporated 90 - 100% control Vernam Preplant incorporated 80 - 90% control Lasso or Dual At cracking stage 60 - 80% control Amiben At cracking stage --- Blazer At cracking stage, post- Less than 60% control emergence over the top Butyrac or Butoxone Postemergence over Less than 60% control the top Basagran Postemergence over Less than 60% control the top Poast Postemergence over 80 - 100% control the top ------------------------------------------------------------------------------- \v*Estimated effectiveness based on rates recommended in this guide. \vEffectiveness may vary depending on factors such as herbicide rate, size of \vweeds, time of application, soil and weather. \b \h 2 'Sandbur' \v \v SANDBUR: ------------------------------------------------------------------------------- Herbicide Time of Application Estimated Effectiveness ------------------------------------------------------------------------------- Balan or Prowl Preplant incorporated 90 - 100% control Vernam Preplant incorporated 80 - 90% control Lasso or Dual At cracking stage 80 - 90% control Amiben At cracking stage --- Blazer At cracking stage, post- Less than 60% control emergence over the top Butyrac or Butoxone Postemergence over Less than 60% control the top Basagran Postemergence over Less than 60% control the top Poast Postemergence over 80 - 100% control the top ------------------------------------------------------------------------------- \v*Estimated effectiveness based on rates recommended in this guide. \vEffectiveness may vary depending on factors such as herbicide rate, size of \vweeds, time of application, soil and weather. \h 2 'Texas Panicum' TEXAS PANICUM: ------------------------------------------------------------------------------- Herbicide Time of Application Estimated Effectiveness ------------------------------------------------------------------------------- Balan or Prowl Preplant incorporated 80 - 100% control Vernam Preplant incorporated Less than 60% control Lasso or Dual At cracking stage 60 - 80% control Amiben At cracking stage Less than 60% control to 80% control Blazer At cracking stage, post- Less than 60% control emergence over the top Butyrac or Butoxone Postemergence over Less than 60% control the top Basagran Postemergence over Less than 60% control the top Poast Postemergence over 80 - 100% control the top ------------------------------------------------------------------------------- \v*Estimated effectiveness based on rates recommended in this guide. \vEffectiveness may vary depending on factors such as herbicide rate, size of \vweeds, time of application, soil and weather. \b \h 2 'Junglerice' \v \v JUNGLERICE: ------------------------------------------------------------------------------- Herbicide Time of Application Estimated Effectiveness ------------------------------------------------------------------------------- Balan or Prowl Preplant incorporated 90 - 100% control Vernam Preplant incorporated 80 - 90% control Lasso or Dual At cracking stage 80 - 90% control Amiben At cracking stage 80 - 90% control Blazer At cracking stage, post- Less than 60% control emergence over the top Butyrac or Butoxone Postemergence over Less than 60% control the top Basagran Postemergence over Less than 60% control the top Poast Postemergence over 80 - 100% control the top ------------------------------------------------------------------------------- \v*Estimated effectiveness based on rates recommended in this guide. \vEffectiveness may vary depending on factors such as herbicide rate, size of \vweeds, time of application, soil and weather. \h 2 'Signalgrass' SIGNALGRASS: ------------------------------------------------------------------------------- Herbicide Time of Application Estimated Effectiveness ------------------------------------------------------------------------------- Balan or Prowl Preplant incorporated 90 - 100% control Vernam Preplant incorporated 60 - 80% control Lasso or Dual At cracking stage 80 - 90% control Amiben At cracking stage 80 - 90% control Blazer At cracking stage, post- Less than 60% control emergence over the top Butyrac or Butoxone Postemergence over Less than 60% control the top Basagran Postemergence over Less than 60% control the top Poast Postemergence over 80 - 100% control the top ------------------------------------------------------------------------------- \v*Estimated effectiveness based on rates recommended in this guide. \vEffectiveness may vary depending on factors such as herbicide rate, size of \vweeds, time of application, soil and weather. \b \h 2 'Purple Nutsedge' \v \v PURPLE NUTSEDGE: ------------------------------------------------------------------------------- Herbicide Time of Application Estimated Effectiveness ------------------------------------------------------------------------------- Balan or Prowl Preplant incorporated Less than 60% control Vernam Preplant incorporated 80 - 90% control Lasso or Dual At cracking stage Less than 60% control Amiben At cracking stage Less than 60% control Blazer At cracking stage, post- Less than 60% control emergence over the top Butyrac or Butoxone Postemergence over Less than 60% control the top Basagran Postemergence over Less than 60% control the top Poast Postemergence over Less than 60% control the top ------------------------------------------------------------------------------- \v*Estimated effectiveness based on rates recommended in this guide. \vEffectiveness may vary depending on factors such as herbicide rate, size of \vweeds, time of application, soil and weather. \h 2 'Yellow Nutsedge' YELLOW NUTSEDGE: ------------------------------------------------------------------------------- Herbicide Time of Application Estimated Effectiveness ------------------------------------------------------------------------------- Balan or Prowl Preplant incorporated Less than 60% control Vernam Preplant incorporated 80 - 100% control Lasso or Dual At cracking stage 60 - 80% control Amiben At cracking stage Less than 60% control Blazer At cracking stage, post- Less than 60% control emergence over the top Butyrac or Butoxone Postemergence over Less than 60% control the top Basagran Postemergence over 80 - 90% control the top Poast Postemergence over Less than 60% control the top ------------------------------------------------------------------------------- \v*Estimated effectiveness based on rates recommended in this guide. \vEffectiveness may vary depending on factors such as herbicide rate, size of \vweeds, time of application, soil and weather.