Weed Control In Pastures & Hay Meadows - Texas A&M AgriLife

11/6/20Reasons Our Pasture Weed Control Doesn‘tWork Spraying too earlyWeed Control in Pastures & HayMeadows Misidentification of the weed Bad environmental conditions Sprayed at the wrong growth stageVanessa Corriher-Olson, Ph.D.Extension Forage SpecialistTexas A&M AgriLife ExtensionOverton, TX Used the wrong product Didn’t calibrate sprayer Didn’t read the label12Methods of Weed Control Manage pasture for maximum production– Soil pH and fertility maintained– Grazing pressure Mowing (mechanical) Herbicide application341

11/6/20Effective Chemical UseEconomic Comparison: Mechanical vs. Chemical40-hp tractor w/ 6’Rotary Mower40-hp tractor w/ 30’boom sprayerLabor cost 15.00 15.00Acres/hour2.9814.88Fixed cost/acre 4.95 1.00Operating cost/acre 6.18 1.37Labor cost/acre 5.04 1.01Herbicide cost/acre 0 9.00 16.17 12.38 Follow label directions for:Item––––Costs ID weed correctly– Use appropriate herbicide– Timing(1.5 pt GrazonNext HL/acre)Total Cost/AcreCorriher-Olson and Cornforth, 2018 DO NOT APPLY during drought 3.79/acre difference!!56https://greenbook.netWeb Source: www.cdms.net7Application rateTiming of applicationGrazing restrictionsCleanup and disposal82

11/6/20Chemical Control StrategiesDuraCor Herbicide Broadcast Aminopyralid Florpyrauxifen-benzyl(Rinskor )– Ground rig– Aerial application Non-Restricted– Used when there are numerous stems/acre(350-400) 12-20 fl oz/acre use rate No grazing restrictions Adjuvant recommendations: Individual Plant Treatment (IPT)– High volume foliar– Basal Treatment– NIS 0.25% v/v– MSO 1% v/v– Cut stump915Usage RatesGrazon P DUsage Rate32-48 oz/A16GrazonNext HLUsage Rate24 oz/AMarsh Elder (Sump Weed)DuraCorUsage Rate12-20 oz/A183

11/6/201920DuraCor Details Active Ingredients:– Rinskor Aminopyralid Non-Restricted-use herbicide 2018 Green Chemistry Challenge Award 95/gallon ( 7.42-14.84/ac) Weed cost comparison:– GrazonNext 48/gallon* ( 9/ac)– Grazon P D 30/gallon* ( 7.5/ac)21274

11/6/20Rezilon (Indaziflam) Pre-emergent Wider application window, 3 followed by 3 Consistent weed control in Bermudagrass andBahiagrass Target species: ryegrass, crabgrass, sandburs,etc. Low use rates3132Conclusions on Indaziflam in TX Should be applied well before expected weedgermination Early is on time! Use rates 3-5 oz/A, no more than 6 oz in 12months No grazing restrictions Comparable to improved forage safety Overall much longer residual control on all grass weeds Greater consistency of control on sandbur compared topendimethalin No haying restrictions @ 3 oz/acre If rates 3 oz/acre, hay may not be harvestedfor 40 days 18-month restriction on planting of cool seasongrasses, 22 months for other crops33 2020 work in progress to evaluate activity on weedyperennial grass species and other annual species435

11/6/20Thistles: Canadian, Bull, Field, Musk,Yellow– The key to thistle control is to treat in the rosette stage– Treat in November through March time frame at propergrowth stage.4445Bahiagrass Cimarron Plus:– 3/8 oz per acre Pastora– 1-1.5 oz/acre Chaparral:– 2-2.5 oz/acre Early in spring prior toseedhead formation No grazing restrictions52536

11/6/20DallisgrassCrabgrass (Summer Annual)– Treatment Options: Roundup (glyphosate) is labeledimmediately after first Bermudagrass hay cut ifcrabgrass is present.– Pastora @ 1.5 oz/acre– Rezilon @ 3 oz/acre 2 applications: Sept/Feb5859Johnsongrass (Perennial)60617

11/6/20Smutgrass 2 ¾ - 4 ½ pints per acre Safe for established bermudagrassor bahiagrass pastures Rates of 4.5 pts/acre or 38 dayhaying restriction Rates 4.5 pts/acre: 60-daygrazing/haying restrictions Be VERY careful under desirabletrees. Velpar L. was first introducedas a brush killer6263Pre-Emergence Grassbur ControlGrassburs / Sandburs Negative effect on hay quality– Reduces value Warm season perennial (cansurvive from one year to the next) Weak stand of desired forage grassbur can take advantage Most important control:– Proper management of desired forage65 2-3 Qt/acre while Bermudagrass is still dormant No grazing or harvest restrictions668

11/6/20Chemical Control Options Roundup (glyphosate) Hayfield: One pint of Roundup per acrewithin 7 days of hay harvest. Grazing Meadows: 10 – 12 oz per acreduring good growing conditions.Bermudagrass will discolor, but recoverwithin 10-14 days. No grazing restrictions.6869Post-Emergence GrassBur Control1-1.5 oz/acre. No more than 2.5 oz/acre within a year.No grazing or haying restrictions.70719

11/6/20Pigweed (Smooth/Common) Summer annual Treat when 2-8” tall Careless weed7778Blackberry (Perennial)Mares Tail /Horseweed– Metsulfuron 60 DF or Cimarron Plus 0.5-1 oz/A– Remedy Ultra 3 pts/acre– Chaparral 3.3 oz/acre– Surmount: 3-4 pts/acre– PastureGard: 3-4 pts/acre– Apply when leaves are expanded and the foliage is darkgreen either before first flower or after fruit drop.808110

11/6/20Carolina Horsenettle (Perennial)8586Pasture Herbicides to Consider Legume Program– 2,4-D– Weedmaster– Outlaw (Agri Star)– Range Star(Agri Star) Generic Weedmaster Non-Legume Program–––––Pastora (Bayer)GrazonNext (Corteva)Milestone (Corteva)Grazon P D (Corteva)Gunslinger (Agri Star) Generic Grazon P D– Cimarron (any; Bayer)– DuraCor (Corteva)8710911

11/6/20http://foragefax.tamu.eduFence Row 1% Grazon P D ¼ % Remedy Ultra ¼% NIS (80% ai)––––All in water.Wet all foliage to glisten on both sides of fence rowAllow brush to stand for 12 months prior to removal.Stay away from desirable trees (2 drip lines) 1-2% Surmount mixture (same NIS level always except with glyphosate)– Same application– Same 12 month waiting period11011212

Weed Control in Pastures & Hay Meadows Vanessa Corriher -Olson, Ph.D. Extension Forage Specialist Texas A&M AgriLife Extension Overton, TX 1 Reasons Our Pasture Weed Control Doesn't Work Spraying too early Misidentification of the weed Bad environmental conditions Sprayed at the wrong growth stage Used the wrong product