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Welcome to the Corteva™ Agriscience
Forage Agronomy Update
These regular technical notes are a seasonal commentary to help those interested in improving grassland and forage productivity on dairy, beef, sheep and equestrian enterprises. This will be our last update of this season, we'll be back next year with more support and advice.
You can claim two CPD points for subscribing to this email update.
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Calling all maize growers! | Last use dates for Corteva grassland herbicides | Weed control using a knapsack | Common diseases in maize | Disease control in maize | Autumn weed control of docks | Late season control of buttercups | Chickweed control in the autumn | Using Forefront T after the last cut for hay and silage | Corteva Forage App | FAQs | BASIS and NRoSO points
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Calling all maize growers!
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We would like to hear your views on silage inoculants. Please take part in our short silage inoculant survey and you could win a Pioneer® prize pack!
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Last use dates for Corteva grassland herbicides
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Active growth is a normal requirement for good translocation of herbicide into roots to achieve a good level of control.
As day length reduces and temperatures drop, active growth will slow down. In response to these changes, consideration must be made when choosing to make a recommendation or when undertaking an application. Further to this, be aware of the cut off dates for application.
Please note that the application window for Leystar® on newly sown leys is now closed - cut off was 31st August.
If the intended use is on established grassland however, applications can continue until 30th September.
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Weed control using a knapsack
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Knapsack treatment of weeds in grassland makes sense if dock or thistle populations are less than 5% (count the number of docks or thistles in a 5m x 7m area to get the % infestation level).
Treatment of nettles, brambles and other unwanted vegetation along fence lines, encroachment from hedgerows and other access areas such as footpaths and gateways are another valued use area.
There are few selective herbicides that have authorisation for handheld equipment use.
Grazon® Pro is one such product. It is an excellent solution for docks, nettles, thistles, brambles and other woody weeds. It comes with a handy measuring device.
The dose rate is 60 ml in 10 litres of water, so a 1 litre pack of Grazon Pro provides for 16 knapsack fills of 10 litre capacity.
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Throughout its growth period, maize is susceptible to infections from specific plant pathogens. These pathogens, which often persist in the crop debris left on the soil, can lead to heightened disease levels, especially when maize is planted consecutively. The severity of these diseases is greatly influenced by moderate temperatures, abundant rainfall, and overcast weather conditions. Consequently, the prevalence of disease is more common in the UK and Ireland, where summers are typically wet, cool, and cloudy.
Fungal infections, in particular, spread when their spores are dispersed by rain or wind onto vulnerable crops. As the growing season advances, the infection ascends from the lower parts of the plant to the upper foliage.
The 5 most common pathogens in the UK are:
- Eyespot (Aureobasidium zeae): Eyespot can affect maize, manifesting as small, round, tan lesions on leaves, which can coalesce and weaken the stalks, leading to lodging.
- Northern Leaf Blight (Exserohilum turcicum): This disease presents as large, cigar-shaped grey-green lesions on maize leaves, potentially reducing photosynthesis and yield.
- Common Rust (Puccinia sorghi): Characterised by its rust-colored pustules on maize leaves, Common Rust can significantly impact the photosynthetic ability of the plants.
- Northern Leaf Spot (Bipolaris zeicola): This disease is identified by oval to elongated brown spots on maize leaves, which can merge and cause blighting under severe conditions.
- Alternaria species (A. tenuissima, A. alternata, A. burnsii, A. Alternaria): These species can cause leaf blight and other diseases in maize, with symptoms including small brown or black spots on leaves, which are particularly problematic during wet seasons in the UK.
These diseases can all compromise the health and yield of maize crops, making management and prevention strategies crucial for farmers in the UK.
How these pathogens impact leaf appearance:
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Employing a multifaceted strategy often yields the best results in controlling maize leaf diseases. Effective measures include minimising leftover maize residue, timely planting, choosing disease-resistant hybrid varieties, and judicious fungicide use. While fungicides are not always necessary for managing these diseases, they can be cost-effective for controlling severe infestations in vulnerable hybrids.
Post-planting, fungicide application remains the only option for growers to manage diseases. Typically, a single treatment is all that’s economically justifiable. The decision to use fungicides is influenced by several factors: the field’s disease history, the preceding crop, tillage methods, the resistance level of the hybrid, its maturity rate, the planting time, the potential yield, the value of the crop, and prevailing weather conditions.
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Autumn weed control in grassland
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Autumn is a good time to control weeds in grassland.
- Perennial weeds such as docks, thistles and buttercups are still actively growing but are now starting to take nutrients down to their roots ready for winter and so will take herbicide down with them.
- It’s an ideal time to control seedling docks and thistles in summer and autumn reseeds. Waiting until they establish and get larger increases the cost of controlling them.
- Generally, there is plenty of grass which means there is less pressure with regard to stock withdrawal periods.
- Weeds in silage and hay paddocks will now all be at a similar size and in a good leafy condition so ideal for herbicide uptake in fields.
- Spring is a busy time, so better to complete some weed control now.
In grazing pastures, docks and thistles may need topping before spraying.
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Late season control of buttercups
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Now is an ideal time to control buttercups, even if flowers are still present. We have seen excellent results in our trials over the years.
Envy offers the opportunity for farmers to rejuvenate tired old grassland which is succumbing to creeping buttercups.
Apply Envy® at 2.0 L/ ha in 200 litres of water. Envy will also give excellent control of any populations of dandelions and chickweed that may also be present.
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Chickweed control in the autumn
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Envy® contains two active ingredients that both have activity on chickweed.
With fluroxypyr and florasulam combined and applied together as the Envy formulation, you can expect high levels of control of both common and mouse-eared chickweed.
Envy also works well when temperatures are cooling and during period where there can be large diurnal fluctuations of temperatures between night and day.
Where frosts are predicted then ensure the application is made at least 14 days before cold weather sets in. If this is not feasible wait and apply the following spring.
Envy has excellent grass safety, is rain fast in 2 hours, but will kill clover.
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Using Forefront T after the last cut for hay and silage
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At this time of the year, many fields that have been used for silage making and hay are turned over to grazing pastures.
In fields where the ability to produce quality forage has been compromised and high populations of docks, thistles and other unwanted weeds are present, consider an application of Forefront® T.
Forefront T is the most effective herbicide available in the market today for lasting control of tough perennial weeds in grassland. It gives the highest levels of control of docks, nettles, thistles, buttercups, dandelions and ragwort. Apply at 2.0 L / ha in 200 litres of water.
Where silage, hay or haylage is produced from this area the following calendar year, any manure subsequently produced from animals fed on this must stay on the farm. This manure should only be spread onto agricultural grassland.
If you would like to find out more or require further advice, please contact Corteva's Technical Hotline, using the contact details below.
Tel: 0800 689 8899
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You can easily access previous editions of the Forage Agronomy Update in the Corteva Forage App.
On the home screen of the Corteva Forage App, click on 'Newsletter' to access the previous updates.
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A: It will give some control but stock need to be kept out until it has died and become less palatable. This is likely to take some weeks so there is a better option. If the problem is in a grazing field, then use Forefront® T and apply via a boom sprayer. This product is very effective and works quickly.
A: This is a smaller pack option for knapsack use with enough product to apply 8 knapsack fills of 10L of spray solution. It gives great control of docks, thistles and nettles, brambles, gorse, and broom. It can be applied through to 31st October.
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BASIS and NRoSO CPD points
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2 BASIS points (1 crop protection and 1 personal development) will be awarded to those subscribing to the Forage Agronomy Update.
2 NRoSO points will be awarded for subscribing.
To receive your CPD points subscribe to the Forage Agronomy Update by clicking here.
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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. © 2024 Corteva. Leystar® contains fluroxypyr, clopyralid and florasulam. Doxstar® Pro contains fluroxypyr and triclopyr. Envy® contains fluroxypyr and florasulam. Forefront® T contains aminopyralid and triclopyr. Grazon® Pro/Spot contains clopyralid and triclopyr. Pas®·Tor® contains clopyralid, fluroxypyr and triclopyr. Thistlex® contains clopyralid and triclopyr.
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