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Forage Agronomy Update header
July 2026
Welcome to the Corteva™ Agriscience
Forage Agronomy Update

These regular technical notes come with CPD points and will help those interested in improving grassland and forage productivity on dairy, beef, sheep and equestrian enterprises. We post frequently on our social media channels, so you’ll want to make sure you’re following @CortevaUK on X and Facebook and @CortevaUKI on Instagram.
Contents
Grassland herbicides following drought conditions | Spraying in hot weather | Preparing grazing ground with heavy weed infestations | Inoculant choices for high dry matter grass and maize silage | Re-seeding intervals | Envy® and Leystar® – newly sown leys | Corteva makes its Groundswell debut | Forage app | Maize herbicide season – tank mixes | FAQs | Contact us | BASIS and NRoSO points
Grassland herbicides following drought conditions
Following prolonged dry weather, delay herbicide applications until weeds have resumed active growth after rainfall. Herbicides depend on active growth for effective uptake and translocation, so treating drought-stressed weeds is unlikely to provide satisfactory control.

By late summer, weeds such as docks, nettles and thistles may have flowered and begun setting seed. In these situations, topping the sward will help reduce seed return and encourage fresh regrowth.

Allow 2-3 weeks for weeds to regrow before applying a selective herbicide, ensuring there is adequate soil moisture and active growth. Where appropriate, applying a top dressing of fertiliser can further stimulate regrowth and improve herbicide performance.
Spraying in hot weather
Avoid applying herbicides during periods of high temperatures or when crops and weeds are under heat or moisture stress. Where applications are necessary, spray during the cooler parts of the day and always follow label recommendations to maximise efficacy and minimise the risk of crop damage.
Preparing grazing ground with heavy weed infestations
Where grazing fields contain large populations of weeds already in flower, topping is a useful first step to reduce seed return and prevent further spread. Allow sufficient regrowth before applying herbicides in late August or early September, provided soil moisture has returned and weeds are actively growing.

Docks and nettles – ProGrassTM

ProGrass provides effective control of docks and nettles in established grassland. Apply to actively growing weeds under good growing conditions to achieve the best long-term results and help improve sward quality.
 
Docks in established grassland (left), nettles in established grassland (right)
Docks in clover-containing swards – ProClova® XL

Where maintaining clover is important, ProClova XL offers selective dock control while preserving valuable clover populations. Apply to healthy, actively growing docks and follow label guidance to maximise efficacy. ProClova XL can be used up to 31 October on established grassland, subject to temperatures. For best control target ProClova XL applications during August and early September. 
 
Docks in clover-containing swards
Ragwort

Ragwort is a biennial species. Many plants will have gone to flower by now, the best long-term strategy is to delay treatment until spring 2027 and target actively growing plants at their rosette stage with Forefront® Pro (not for use in horse paddocks or cutting leys). Correct timing will provide more reliable control than spraying stressed plants in flower following drought.
 
Ragwort treatments are now best left until the spring
Thistles

Where possible, postpone treatment until 2027 and use Thistlex® Pro when thistles are actively growing. Spraying at the correct growth stage under favourable conditions will give the highest levels of control and reduce the need for repeat applications.
 
Thistles are now beyond ideal treatment windows
 
Inoculant choices for high dry matter grass and maize silage
Hot, dry conditions are leading to higher dry matter grass, maize and wholecrop silages. While these crops can produce excellent feed, they are often harder to consolidate, leaving more air in the clamp and increasing the risk of heating caused by yeasts and moulds.

In these situations, inoculant choice becomes increasingly important. Products containing Lactobacillus buchneri are proven to improve aerobic stability by producing compounds that inhibit yeasts and moulds, helping keep silage cooler and reducing dry matter losses during storage and feed-out. 

Heating and losses of unstable silage with different dry matter content
Heating and losses of unstable silage with different dry matter content
Modified after H.Honig and M.K. Woolford (1980), source: Changes in silage on exposure to air., pp.76-87: “Forage conservation in the 80's”; (ed. C. Thomas), Occasional Symposium No.11, British Grassland Society, Brighton; 1979.
*Ref Spiekers, H. (2004) Top Agrar. 2/2004. pR 10-12.

For high dry matter grass silage where aerobic spoilage risk is particularly high, 11A44 is specifically designed to improve stability in the later stages of fermentation and reduce heating losses. 
Silage inoculant decision tree
Combined with good clamp management, rapid filling, thorough consolidation and effective sealing, the right inoculant can help preserve feed quality, reduce losses and maximise the value of every tonne harvested.

Learn more about our silage inoculant range here.


Re-seeding intervals
The hot dry conditions will mean that many grass leys have become stressed and may have thinned, reducing productivity and allowing weed ingress. Before planning any grassland renovation or re-seeding, check the product label for minimum intervals between herbicide application and sowing. Following these restrictions helps avoid crop establishment issues and protects the success of the new ley.
Envy® and Leystar® – newly sown leys
Envy and Leystar are valuable options for controlling broad-leaved weeds in newly sown leys. Early weed control reduces competition, helping young grass establish quickly and produce a productive, long-lasting sward.
Borad-leaved weeds in a newly sown ley
Clover-containing newly sown leys

Where new leys contain clover, choose a clover-safe option such as ProClova® XL in spring 2027.This provides effective dock control while maintaining the benefits that clover brings to the sward.
Corteva makes its Groundswell debut
Groundswell 2026 marked Corteva's first attendance at the event, providing a valuable opportunity to connect with growers, agronomists and industry partners who share a passion for building resilient and sustainable farming systems.

As agriculture continues to evolve, Groundswell offers the perfect platform to explore how innovations in biologicals can work together with a range of farming systems to support productivity, soil health and long-term sustainability

We showcased our growing portfolio of biologicals including BlueNTM, Kinsidro® Grow+, Harbest® and Resid MG.

We engaged in practical discussions around soil health, crop resilience and regenerative farming practices. The strong interest and positive conversations reinforced the importance of science-led solutions that help farmers balance productivity, profitability and sustainability.
The Corteva team at Groundswell
Click here to find out more about our Biological solutions.
Forage App
The Forage App provides quick access to product labels, technical information, best practice guidance and stewardship advice. Agronomists and farmers are encouraged to use it as a convenient reference when planning and applying herbicides.
Forage App
Maize herbicide season – tank mixes
It has been a successful year for Principal® Forte, Corteva’s new maize herbicide. The safener technology built into the formulation has proven itself yet again in what has been a stressful year due to hot dry conditions. The ability to tank mix safely with Starane® Hi-Load has been well received.

As we plan ahead for 2027, please let your local area manager or our hotline team know of any tank mix requests (foliar nutrition or herbicide products) that you have in maize with our herbicides so that we can get these tested well in advance for you. 
FAQs
Q: Which product can be used for hemlock control using knapsack sprayer?
A: Grazon® Pro can be used through a knapsack as spot treatment at a rate of 60 millilitres in 10 litres water, when weeds are actively growing.

Q: Can Thistlex® Pro be used in game cover mixes?
A: There is no approval or EAMU for the use of Thistlex Pro in game cover mixes, but there is currently an EAMU for Thistlex®.

Q: When does the approval for Thistlex change to Thistlex Pro?
A: Thistlex is not being revoked; however, no further product will be manufactured. Once existing stock has been exhausted, we will switch over to Thistlex Pro. Thistlex Pro is already available.

Q: Why is Forefront® T going?
A: Forefront T contains a higher loading of triclopyr, which is not being supported through the renewal process of this active. We are therefore switching to Forefront® Pro. Other triclopyr containing solutions are being supported, with the exception of Thistlex, which has been replaced by Thistlex Pro.
Contact us
Our hotline team is on hand to answer any queries or concerns you have. Please do not hesitate to get in touch via 0800 689 8899, ukhotline@corteva.com, or by submitting an enquiry.

Click here to find the contact details of your local forage specialist.
BASIS and NRoSO points
Subscribing to Corteva Agriscience's Forage Agronomy Update gives eligibility for 2 BASIS points and/or 2 NRoSO points.

2 BASIS points (1 crop protection and 1 personal development) will be awarded to those subscribing to the Forage Agronomy Update. Please include course name ‘Forage Agronomy Update’ and ref number: 432838524145, on the training record and send to cpd@basis-reg.co.uk. These details are valid until 31 May 2027.

2 NRoSO points will be awarded for subscribing. Please include course name ‘Forage Agronomy Update’ and ref number: NO505980f on the training record and send to nroso@basis-reg.co.uk.These details are valid until 31 August 2026.
BASIS and NRoSO logos
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USE PLANT PROTECTION PRODUCTS SAFELY. Always read the label and product information before use. For further information including warning phrases and symbols refer to label. ®™ Trademarks Corteva Agriscience Limited and its affiliated companies. All other brand names are trademarks of other manufacturers for which proprietary rights may exist. All manufacturers trade names and trademarks are duly acknowledged. © 2026 Corteva. ProGrass™ contains halauxifen-methyl (Arylex™ active), fluroxypyr & triclopyr. ProClova® XL contains florpyrauxifen-benzyl and amidosulfuron. Forefront® Pro contains aminopyralid and fluroxypyr. Thistlex® Pro contains clopyralid and halauxifen-methyl. Envy® contains fluroxypyr and florasulam. Leystar® contains fluroxypyr, clopyralid and florasulam. BlueNTM contains Methylobacterium symbioticum. Kinsidro® Grow+ contains 0-0-13 potassium fertiliser with micronutrients and biostimulant substances. Harbest® contains 15% w/w ureic nitrogen and 12% water soluble calcium oxide. Resid® contains Glomus iranicum var. tenuihypharum. Principal® Forte contains nicosulfuron, rimsulfuron, dicamba and isoxadifen. Starane® Hi-load HL contains fluroxypyr. Grazon® Pro contains clopyralid and triclopyr. Thistlex® contains clopyralid and triclopyr. Forefront® T contains aminopyralid and triclopyr.