Spring Weed Control - Nufarm
Spring weedcontrolTechniques, products and methodsto reclaim pasture from spring weeds
A guide to spring weed controlIntroductionThe productive life of perennial pasture is to some extent dependent onlimiting the negative effect of weeds as early as possible. Some weedsare linked to animal health issues and all weeds compete with productivepasture species for light, space, moisture and soil nutrients.Spraying broadleaf weeds in late autumn or early winter with a phenoxyherbicide is a commonly accepted practise. However, there are severalsignificant weeds that cannot be effectively controlled with an autumn /early winter spray because they emerge mainly in spring.As soon as soil temperatures start to climb in early September these springgerminating weeds start to appear. A number of spring weeds have alsobecome more evident in recent years, particularly in dairy pastures.This guide covers three key areas of spring weed control: Spring weed control in established pasture Control of large spring weeds in pasture Californian thistle controlIf you have a specific weed of concern or require more informationcontact a Nufarm representative on 0800 NUFARM (683 276).2
A guide to spring weed controlContents4Spring weed control in established pasture4Timing5Weed identification9Herbicide selection10 Pasture management for application11Spring weed control and timing reference chart12Controlling large spring weeds in pasture13Californian thistle control13 Biology14 Controlling Californian thistles15 Control strategies17 Get Californian thistle control with the 2x2 Spray Plan 3
A guide to spring weed controlSpring weed control in established pastureThere are three key steps to effective spring weed control inestablished pasture - timing, weed identification and product selection.1. TimingOne of the most common mistakes made with spring weed control isspraying too late. Just because the weeds aren’t immediately obvious inthe pasture doesn’t mean they’re not there.Spring germinating weeds can be present under the pasture cover asseedlings and smaller plants. Following grazing, these seedling weedsare exposed to sunlight and are likely to develop in the pasture to thepoint where they will be severely production limiting.If these weeds are left until they are mature and flowering, then in mostcases it’s too late. They will be very difficult, if not impossible to control.The key is to time application to kill the bulk of the germination withoutletting early germinating weeds get too big for effective control.Changeable spring weather often results in delays in application.Identify paddocks where spring germinating weeds are present asearly as possible, allowing plenty of time for application.4
A guide to spring weed control2. Weed IdentificationThe range of weed species identified in the paddock will determine themost effective treatment. See the following pages for some of the morecommon spring germinating weeds.FleabaneProlific and fast growing, it prefers light soils and canwithstand dry conditions. Fleabane produces a largenumber of seeds which can germinate in both springand autumn. Spray at seedling to small rosette stagewith Baton 800WSG.ButtercupMost common in dairy pastures, particularly on less freedraining soil types. Creeping and giant buttercup canbe particularly invasive and are not easy to control.Preferred pasture spraying option is Valdo 800WGplus Bonza applied preflowering. May require twoapplications in the spring to ensure adequate control.DandelionDandelion is often a problem in many pastures.Effective control is only possible during the seedlingstage because the plant is both deep rooted andperennial. Taproot re-growth is poorly controlled. Innew pastures, spray Baton 800WSG early before thetaproot becomes established. Note: once sprayed,dandelion plants can take several weeks to die.5
A guide to spring weed controlDockWhile seedling docks can be controlled with Baton 800WSG,established docks will not be well controlled. Establisheddocks are best controlled in early spring with either Dockstar or Charter . If other weeds need to be controlled as well asdocks, a tank mix of Dockstar Baton 800WSG can be used.FathenFathen is an extremely fast-growing weed with excellentsurvival mechanisms. In good conditions it can growup to 1m high before flowering, but in dry situations itwill flower and produce seed before it is 4cm high. Italso has a very thick waxy layer which coats the leavesin dry weather. This is designed to hold moisture in theplant, but it is equally effective at preventing absorptionof herbicides. Fathen can grow densely in spring-sownpastures. Baton 800WSG sprayed pre-flowering gives themost effective control.Hedge MustardA tap-rooted annual, hedge mustard (often mistakenlycalled wireweed) can be a problem in newly-sown oropen pastures. Seedlings form rosettes which in turnquickly produce upright flowering stems 1m or morehigh. Stock avoid this plant, leading to poor pastureutilisation. Control is best achieved with an earlyapplication of Baton 800WSG at seedling to rosette stage.NettlesNettles are fast-growing, and can quickly choke out newgrass and clover. Baton 800WSG applied at the seedlingto small plant stage is a very effective method of control,usually performing much better than MCPA and MCPBherbicides. Higher rates of Baton 800WSG at largergrowth stages will only suppress the plant, not kill it, soearly application is best.6
A guide to spring weed controlOxeye DaisyA perennial weed that becomes more prominent inspring. Often found in open pastures and on sidelings.A very difficult weed to control but where a tank mix ofBaton 800WSG, Valdo 800WG and Bonza is used, moreconsistent levels of control are achieved.PennyroyalPennyroyal is now prevalent in many areas anddifferent soil types and is becoming predominant in runout pastures. Invasive and highly unpalatable to stock,pennyroyal forms dense mats of vegetation in pastures,causing inefficient feed utilisation, and taints the milkof lactating dairy cows if they do eat it. Baton 800WSGsprayed pre-flowering gives the most effective control.RagwortRagwort is a very difficult weed to control and spreadseasily. It grows all year round and is establishedfrom both seeds and old existing roots. Ragwort is apoisonous plant to stock and becomes more palatablewhen sprayed, so stock must be kept away until ithas died down. When plants are small, boom spraywith Baton 800WSG or Relay Super S. Large rosettesor ragwort regrowth should be spot sprayed withConquest .7
A guide to spring weed controlStorksbillStorksbill is a low-growing, tap-rooted annual that thrivesin low fertility pastures. It can cause problems in bothnew and established pastures, particularly in spring.Seedheads damage animal pelts. Storksbill has also beenrecorded as causing staggers and photo-sensitisation inlambs and cattle. Baton 800WSG is extremely effective atcontrolling storksbill up to the small rosette stage. Moremature plants will only be suppressed. One well-timedspring application will also break the seed cycle andreduce the population in following seasons.Wild turnipFast-growing and persistent, wild turnip is an annualbrassica which is common in pastures on a wide rangeof soils. Flowering stalks can reach 1m high causing lossof pasture yield through competition for resources.Baton 800WSG will give effective control when appliedearly, up to rosette stage. Once the plant matures its rootreserves make it harder to control.Willow weedWillow weed is a sprawling summer annual found inmoist, well-aerated soils. Highly invasive, it can smotherlarge areas of both newly-sown and establishedpastures. It is generally unpalatable to stock, but deathshave been recorded overseas. Willow weed producesa large volume of seeds which remain viable for sometime, and it can also reproduce from small pieces ofbroken stem. Optimal control is achieved by sprayingBaton 800WSG at seedling stage (less than 75mm high).Established plants are poorly controlled.8
A guide to spring weed control3. Herbicide SelectionMost common spring germinating weeds can be controlled with theuse of Baton 800WSG, while some of the harder to kill weeds require theaddition of Valdo 800WG and Bonza.Baton 800WSGBaton 800WSG is a phenoxy herbicide that can be veryuseful in spring. Baton 800WSG provides effective controlof most common spring germinating weeds. Baton800WSG is an advanced formulation, containing 800g / kg2, 4-D as the dimethylamine salt. Formulated as a granule,Baton 800WSG is low odour, is non-volatile and causesless damage to valuable clovers. Baton 800WSG appliedin spring will have some affect on clover growth, but clovernormally recovers well and any suppression is more thanbalanced by the benefits of less weed competition.For spring weeds Baton 800WSG is typically applied at 1.5 - 2kg/ha (see table page 11;always refer to the Baton 800WSG label before application). Recommended waterrates are 100 - 300L/ha. Do not apply Baton 800WSG to paddocks shut for hay or silage,or to pastures containing chicory or plantain.Valdo 800WGValdo 800WG is a clover friendly herbicide that is idealas a tank mix partner for Baton 800WSG when a widerweed spectrum is required. Valdo 800WG should alwaysbe applied in conjunction with Bonza spraying oil foreffective control. Valdo 800WG controls harder to killweeds such as perennial buttercups, cresses and oxeyedaisy. Be mindful of damage to young clover. NB: Referto the Baton 800WSG label.Rates of application vary between 30 and 65g / ha dependent on the targetedweed. Apply Valdo 800WG in 100 - 300L of water with Bonza at a rate of500ml / 100L of water. Valdo 800WG has a 14 day grazing withholding period.Susceptible crops such as brassicas, sunflowers, lupins and beans should not beplanted until three months after the application of Valdo 800WG.9
A guide to spring weed controlBonza Bonza is a specially formulated blend of oils designedto enhance wetting, spreading and uptake ofherbicides. Bonza also aids in the management ofspray droplet quality and survival. Apply Bonza at arate of 500ml - 1L per 100L of water, as per the relevantproduct label.Pasture management for applicationGraze paddocks before spraying to expose target weeds, andto reduce clover leaf area to minimise clover damage. Let thepaddock freshen for 2 - 3 days. Try to spray as soon as possiblethereafter (weather permitting). Wait 10 - 14 days (14 days if Valdo800WG is applied) before the paddock is grazed again, to allowherbicides to move through the weed plants.Three tips for spring weed control Start looking for spring weeds early (September) Identify the full range of weeds that need to be controlled Select the right product for the job.10
A guide to spring weed controlSpring weed treatment and timing reference chartWEEDAnnual buttercupsCanadian fleabaneBaton800WSG800WSG(kg / ha)Valdo800WG(g / ha)1 - 1.550 - 651.5 - 2DandelionDockFathenNettles50 - 65Seedlings to small rosettes. Creeping yellowcress is best controlled with a Baton800WSG, Valdo 800WG and Bonza mix.1 - 1.5Seedlings1.5 - 2Small rosettes2 - 2.52 - 4 leaf seedlings only1-2Apply before floweringGiant buttercupHedge mustardApply before flowering. Baton 800WSGcontrols annual species only.Seedlings to small rosettesCresses1.5 - 2STAGE65Apply before flowering1 -230 - 65Seedlings to small rosettes1.5 - 2.530Seedlings to young plants65Apply to young seedlings.Suppression only. A Baton 800WSG,Valdo 800WG and Bonza mix willprovide a more consistent level ofcontrol.Oxeye daisyPennyroyal1.5 - 2Prior to flower stalk development. Highrate useful as a salvage treatment forflowering pennyroyal.Ragwort2-3Seedlings to small rosettesStorksbill1.5 - 2Seedlings2-3RosettesWild turnipWild radishSeedlings only. Established plants arenot well controlled.1.51.5 - 2.530 - 65Seedlings only. Established plants arenot well controlled.65Seedlings. No taller than 75mm. NOTE:Willow weed is commonly mistakenfor water pepper. Water pepper haslighter green leaves and no blackmarkings. Baton 800WSG will notcontrol water pepper.Willow weed2-311
A guide to spring weed controlControlling large spring weeds in pastureA number of spring weeds have multiple germinations in a season. Earlygerminations of weeds may be too large for effective control with Baton800WSG or Valdo 800WG. In this case Conquest is an ideal spot sprayingsolution. Conquest will not only control larger spring weeds in your pasture butalso large thistles and ragwort plants. Conquest is also ideal for spot sprayingany brushweeds that need attention.Conquest does not damage grass but is very damaging to legumes.Target weeds carefully to avoid over spray.Conquest-treated nodding thistle13 days after applicationConquest-treated nodding thistle48 days after applicationPasture weeds – spot application using ConquestWEEDRagwort and thistles(excluding Californianthistle)60Fennel, goats rue,hemlock, horehound,inkweed, nettles60Alligator weed, fieldbindweed, Californianthistle, Cape weed,dock, sorrel12Knapsack orbattery poweredmotorbikesprayermL/10 Litres60High volumegun andhosemL/100 LitresNotes200Rosette and multi crowned plants250Early flowering plants250Apply during active growthfrom full leaf to early flowering.300Californian thistle – retreatmentmay be required
A guide to spring weed controlCalifornian thistle controlCalifornian thistle is probably the most invasive broadleaf weed inNew Zealand pastures with reports estimating 700 million in lostpastoral farm revenue each year. This perennial thistle limits farmproductivity by reducing both pasture production and pastureutilisation. Trials show that 30% ground cover with Californian thistle(13 stems/m2) can cut ewe liveweight gains by 29% over a 12-monthperiod. Californian thistle also triggers scabby mouth disease.BiologyIn established pasture, seedlings rarelycontribute to the spread of Californian thistle.Seeds will not germinate under vegetationand young seedlings are highly sensitiveto shading.Instead, Californian thistle reproduces froman extensive creeping horizontal root system.In spring, shoots develop from buds along theunderground roots. The first shoots to developprevent the adjacent live buds along the root from developing, andthey then remain dormant. As a result, these first shoots grow strongly,supported by a large root system with minimal competition for nutrientsand light. Their job is to supply nutrients to the root system during summer.They die in late autumn, but leave a new generation of over-winteringroots to continue the cycle the following spring.This system allows Californian thistle to spread rapidly within paddocks.Distributing fragments of roots containing buds, either via livestock orcultivation, can also contribute to the weed’s spread.13
A guide to spring weed controlControlling Californian thistlesBefore planning to spray Californian thistle, please note these key points: Spread is almost entirely from roots. Roots only survive for about 12 months and are replaced annually. The amount of vegetation produced by the thistle shoots during agrowing season (Sept - April) will determine the amount of root thatover-winters. Over-wintering bud numbers are directly related to root mass(1 - 3 buds /gram of roots).There is no “one-shot” magic bullet for effective control of Californian thistle. It canbe killed in established pastures using selective herbicides, but to be successfulthese require multiple applications each year for at least 2 years.To control established thistle populations in existing pastures, it is essential toreduce the numbers of over-wintering root buds in the soil. During the growingseason (typically September to April) as much as possible of the above-groundthistle vegetation must be removed, for as long as possible,to reduce the plant’s ability to create new roots.Renewal of old pastures using the Programmed Approach is particularlyeffective at controlling Californian thistle. This is a 12 - 15 month process involvingthree applications of CRUCIAL (autumn, spring, autumn) with two interveningcrops, typically a winter active ryegrass (annual or Italian) or cereal and asummer crop such as brassicas, cereals or maize. Californian thistle in the summercrop must be sprayed with a suitable herbicide e.g. Archer 750 at 200-400 ml/ha.14
A guide to spring weed controlControl strategiesThe mow and spray option (A) is the preferred option. When mowing isnot an option, a herbicide programme (B) will be the next best solution.A) Mow and spray Mow when 20 - 30% of shoots reach the hardball stage (Nov). Boom spray re-growth in January with appropriate herbicide. Spray again in March to kill newly-emerged shoots. Repeat for the next 1 - 2 years until thistles are controlled.Mowing shoots close to the ground stimulates growth of new shoots fromdormant root buds, or from buds at the base of cut stems. By increasingthe shoot to root ratio, and weakening the roots as they put moreresources into generating shoots, the plant becomes more susceptibleto herbicides.B) Herbicide programme Apply appropriate herbicide via boom spray or weed wiper whenthistle shoots are at the early flower bud stage (Dec-mid Jan). Apply herbicide again in March to kill newly-emerged shoots. Failureto apply this second treatment is the main reason for poor control ofCalifornian thistle. Repeat for the next 1 - 2 years.Boom spray herbicide optionsProductsUse rateCommentsRainfastnessBaton 800WSG1.5kg / haMay cause minorclover suppression - cloverrecovers quickly6hrsThistrol Plus4L /haSafe on clover2hrsAgritone 7502L /haWill suppress clover2hrs*Some alternative products are rainfast in 12 hrs. Baton 800WSG, Thistrol Plus and Agritone 750 give you much more applicationflexibility during spring weather conditions.15
A guide to spring weed controlSituations that call forThistrol Plus If you need extra clover safety. Paddocks shut up for hay or silage,or paddocks that have not beenrecently grazed. When showers are likely 2 hours afterspraying (it’s rainfast in just 2 hours).For best results Graze before spraying to expose thistles and reduce clover leaf areato minimise clover damage. Do not apply Baton 800WSG or Agritone 750 to pastures shut for hay or silage.Recommended water rates: Ground application – 100 - 300L water / ha (300L for dense thistle populations). Aerial application – minimum 60L water/ ha.Why Baton 800WSG is betteron Californian thistle Half the cost of many alternative herbicides;more effective. Faster brownout and leaf drop. Stock can graze under thistles more quickly. Better quality pasture from reducedweed competition and improved grazingmanagement.16
A guide to spring weed controlGet Californian thistle control withthe 2x2 Spray PlanTrial results from Hinuera in the Waikato and Mid Canterbury have shownthat spraying twice (December and March) with Baton 800WSG orThistrol Plus for two consecutive thistle growing seasons greatly reducesthistles compared with a once a year spray programme.Refer to the tables below.Why the 2x2 Spray Plan worksThe biology of Californian thistles (as discussed on page 4) means thatrepeated treatment is needed to diminish thistle numbers. Table 1 showsthat in the first year of treatment one spray reduced thistle numbers by36% and two sprays by 73%. Whereas, Table 2 shows that two sprays thefollowing growing season reduced thistle numbers by 93%. In summary,two sprays for two growing seasons is is one of the most effective3530301502 Spray5-73%1 Spray10-37%20151050-93%2 Spray20251 Spray-36%Untreated25LIVE THISTLE STEMS/M235UntreatedLIVE THISTLE STEMS/M2methods for controlling Californian thistles.Table 1: Thistle numbers in the springTable 2: Thistle numbers in the spring followingfollowing treatment the previous year.treatment the previous 2 growing seasons.17
A guide to spring weed controlWhat farmers are saying“In some paddocks the Californians were up to the window of the truck and higher.Where we’ve sprayed twice over two growing seasons, the Cali’s are wiped out!”Brian Dickison - Waikaka“When we came here four years ago, the Californian thistles were so thick youcouldn’t get into some paddocks with a motorbike. Now we’ve got those hectaresback.” John Gilkison - SouthlandThe most expensive control measure for Californian thistles is doing nothing!18
A guide to spring weed controlWeed wiper herbicide optionPRODUCTSUse rateArcher 7501:100 dilution (100ml/10L)CRUCIAL1:30 dilution (333ml / 10L water)Associate 600WDG1:1000 dilution (10g / 10L water)For dense infestations, a secondpass with the wiper in the oppositedirection will improve control.19
Nufarm NZ6 Manu Street, OtahuhuPO Box 22-407, Auckland 1640, New ZealandPhone 09 270 4157nzinfo@nufarm.comwww.nufarm.co.nzPhotos of Fathen and Hedge Mustard are courtesy of Trevor James. Agritone, Archer, Conquest, Charter, Associate, Thistrol, Baton, Valdoand CRUCIAL are all Registered Trademark of Nufarm Australia Ltd. Bonza and Dockstar are registered trademarks of Nufarm Limited The Nufarm Guide to Grassmanship is registered trademark ofNufarm Australia Limited. Programmed Approach is a trademark of Wrightson Seeds. The 2x2 Spray Plan is a trademark of Nufarm. Nufarm 2020NUF0327-02/ 20
A guide to spring weed control Spring weed control in established pasture There are three key steps to effective spring weed control in established pasture - timing, weed identification and product selection. 1. Timing One of the most common mistakes made with spring weed control is spraying too late.
3.2 Chemical Weed Control 10 3.3 Thermal Weed Control 14 3.4 Biological Weed Control 15 4.0 Natural Areas Weed Management 16 4.1 Purpose 16 4.2 Limitations 16 4.3 Study Area 16 4.4 Weed Management Site Prioritisation 18 4.5 Weed Monitoring 20 4.6 Weed Prevention 22 4.7 Weed Control 24 4.8 Partnerships 28 5.0 Parks and Urban Landscaping
W-253 2018 NORTH DAKOTA WEED CONTROL GUIDE Compiled by: Rich Zollinger Extension Weed Science Contributors: Mike Christoffers Research Weed Science, Weed Genetics Caleb Dalley Research Weed Science, Hettinger R&E Center Greg Endres Extension Area Agronomist, Carrington R&E Center Greta Gramig Research Weed Science, Weed Ecology Kirk Howatt Research Weed Science, Small Grains/Minor Crops
control, weed control, weed control '. Of course there are other important tasks, but weed control is surely one of the most vital! It is important to achieve good weed control in the 1m2 around each seedling. However the amount of ground disturbance should be kept to a minimum as open ground is an invitation to fresh weed establishment.
Introduction to Weed Science and Weed Identification . Definition of a Weed A plant growing where it is not wanted (Oxford Dictionary) Any plant or vegetation, excluding fungi, interfering with the objectives or requirements of people (European Weed Science Society)
Your guide to weed control in new pasture Weed control programmes for newly sown pasture There are two ideal times to spray for weeds in new pasture; prior to the first grazing and after the first grazing. The stage you choose is dependent on the species and size of the target weeds and will determine the correct product(s) to use. Pre-Grazing
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weed control strategies in the best possible way with the goal of maintaining weed densities at manageable levels while preventing shifts in weed populations to more difficult-to-control weeds. Combining as many of the following practices as possible will allow you to design an IWM program: † Avoid weed establishment; eliminate individual .
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