Top tips for getting the most out of herbicides

Heavy reliance is often placed on herbicides to target a wide range of weeds, so it is important to maximise their performance in order to get the most out of applications this spring.

At this time in the arable season, many farmers across the country will be planning their spring herbicide programmes and will be hoping to achieve smooth and e ective weed control in the most e cient way.

Adam Espir (pictured), commercial Adam Espir (pictured), commercial technical manager at FMC, says growers can achieve successful knock down of weeds this spring if they take into consideration the four key factors which can impact the performance of herbicides.

Working around weather conditions

Mr Espir explains that weather is a factor that can greatly help or hinder weed control during the spring, so it is important not to take it for granted.

“Weeds thrive in warm and wet weather, so after a prolonged period of these conditions a welldeveloped canopy of weeds can quickly appear.

“This means it’s important to pay attention to the weather conditions throughout the spring, but particularly when you’re getting to the stage of making applications,” he says.

Herbicide applications are best made when weeds are small and actively growing, but Mr Espir points out that sometimes this early growth stage, which is ideal for herbicide activity, doesn’t always coincide with ideal spraying conditions.

“If conditions are particularly dry, weeds can develop waxy leaves and stems which help the plant to retain water. However, these can then make it di cult for the plant to take up herbicides, potentially reducing e cacy.

“In these circumstances, delaying application until after a period of wet weather and allowing weeds to begin actively growing again can achieve better success,” he recommends.

On the other hand, if there is a prolonged period of heavy wet weather, it may be hard to travel on the elds – meaning spraying plans may need to be postponed until the ground is drier.

“Weather is important whichever way you look at it, so growers need to plan their applications in consideration of the weather and understand how it can impact herbicide performance, as best as possible,” he says. possible,” he says.

Reducing resistance pressures with a tank mix partner

Mr Espir explains the use of a tank mix partner is also important when applying herbicides, but especially when using sulfonylurea (SU) herbicides. SU herbicides have been a mainstay of the arable grower’s armoury for over 30 years and, due to their reliability, remain an important part of a grower’s toolkit in the spring.

“A tank mix partner is a second herbicide that’s used alongside the originally chosen product. Tank mix partners help to prolong the life of SU herbicides such as Ally Max SX by reducing the risk of resistance, so I would always encourage growers to use another herbicide with a di erent mode of action in tandem with their chosen SU herbicide.

“By bringing in a di erent mode of action, growers can increase the speed of kill on weeds, with visible results seen much sooner. They will also be able to broaden the spectrum of weeds targeted with just one application.”

“Currently, very few broadleaf weeds have been con rmed as resistant to SU herbicides. A small number of mayweed, chickweed, and poppy populations have been identi ed as resistant, but thanks to tank mixing, this resistance is manageable and is unlikely to become a big issue,” he explains.

Mr Espir advises any growers concerned about resistance or looking to learn more about potential tank mix partners to speak to their agronomist.

Using the correct equipment for good coverage

“Coverage is determined by the equipment used and the application rate of both herbicide and water, so growers need to thoroughly plan this before applications,” says Mr Espir.

“For example, if the crop is particularly dense, applications should be made with a high-water volume, up to 300 litres/ha.

“Using sprayer nozzles which are appropriate for the speci c target species can also help to ensure the weeds are well covered by any applications.

“Always check the herbicide label before use to ensure you’re applying it at the correct rate and with the right equipment,” he adds.

Sprayer hygiene

The nal step to consider is sprayer hygiene, arguably one of the most important practices farmers should undertake when it comes to spraying.

“If sprayers aren’t properly cleaned out, it could cause devastating impacts to crops and leave growers out of pocket,” warns Mr Espir.

Residues from herbicides can linger in sprayers after use, which can cause blockages and reduce the e cacy of the sprayer.

There is also a heightened risk of contamination, as residues can wash out in subsequent applications, potentially causing damage to sensitive crops.

“Following good hygiene practices is critical. Thoroughly wash out sprayers soon after each use to avoid any issues,” he says.

The use of a liquid sprayer cleaner, such as All Clear Extra, speci cally formulated for SU herbicides, can help to wash out any remaining residues.

Mr Espir adds that it is particularly important for growers to use a tank cleaner and carry out a full washout procedure on sprayers if they are moving on from a cereal to a broad-leaved crop such as sugar beet, OSR or potatoes, as residues could cause signi cant damage.

“By taking the weather into consideration, using a tank mix partner with suitable equipment and carrying out proper sprayer hygiene, growers should be able to successfully control emerging spring weeds and get the most out of their investment this spring,” he concludes. FG

Wild oats are one of the most competitive grass weeds, with just one plant per square metre able to reduce winter cereal yields by as much as 1%.

Cultural tactics and accurate spraying essential for e ective wild oat control

Growers throughout the UK must adopt a range of chemical and non-chemical strategies to protect cereals from the increasingly problematic threat of wild oats this spring.

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That is the advice from Adama’s herbicide technical specialist, Dr Bill Lankford, who also urges spray operators to be extra diligent when treating advanced crops where a dense canopy could prevent herbicides from reaching underlying wild oat plants.

Wild oats, of which there are two species, are one of the most competitive grass weeds, with just one plant per square metre able to reduce winter cereal yields by 1%.

As with any weed, cultural and chemical tactics are needed to achieve adequate levels of control, with the prevention of seed production a priority, especially as the typical array of cultural controls commonly used to tackle weeds such as black-grass (later autumn drilling, spring cropping, ploughing) often prove less effective against wild oats due to the protracted emergence of both species and their ability to germinate from depths of up to 15cm.

“Rogueing is therefore essential in crops which are heavily infested by wild oats,” advises Dr Lankford, who also advocates the use of weed mapping in June and/or July when the two species of wild oats are more easily identifiable: “One of the key difficulties in controlling wild oats is that the two species, Avena sterilis ssp. Ludoviciana (winter wild oats) and Avena fatua (common, or spring wild oats), are almost

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Good machinery hygiene

Dr Lankford also stresses the importance of maintaining good machinery hygiene to limit the spread of wild oat seeds and has seen good levels of control where crops have been established by direct drilling or with minimal soil disturbance – as this can help to reduce the germination of dormant wild oat seeds.

Dr Lankford recommends using an appropriate herbicide to spray off the worst affected areas prior to the shedding of seeds which typically commences from late June onwards: “While growers shouldn’t rely solely on herbicides such as Topik (240g/ litre clodinafop-propargyl and 60g/ litre cloquintocet-mexyl) to control wild oats in cereals, Axial Pro (55g/ litre pinoxaden) to control wild oats in barley, or Falcon (100g/litre propaquizafop) in broad-leaved crops, chemical options such as these obviously play an important role. They should, however, be used with caution to maintain the required level of spray coverage and application accuracy.”

Dr Bill Lankford advocates the use of chemical and non-chemical methods to control wild oat infestations.

Maximising efficacy

To maximise the efficacy of these and other wild oat herbicides, Dr Lankford offers the following advice: “Spray slowly at a sensible boom height and with an appropriate water volume to optimise coverage of the target weeds.”

He elaborates by explaining: “The efficacy of wild oat herbicides is complicated by the vigorous spring growth rates of commercial crops which can produce a canopy which shields the emerging wild oats from spray treatments. Competing spray requirements during the spring also put additional pressure on sprayer workloads, with growers often opting to apply a lower water volume at a high forward speed to cover more ground within a specific window of opportunity.

“This can be counter-intuitive when tackling wild oats, where getting the optimal biological efficacy from the herbicides being applied is essential. Products such as Topik should therefore be applied in a way that ensures maximum spray coverage: it might be feasible to reduce water volumes for early spring applications when wild oat plants aren’t protected by the crop’s canopy, but for applications beyond GS31 growers must use at least 200 litres of water per hectare. They should also consider if their nozzle choice will adequately enable the spray to be deposited on wild oat leaves in the crop canopy and should set the boom height to 50cm above the canopy and restrict the sprayer’s forward operating speed to no more than 12kph to ensure full coverage.”

Irrespective of which growth stage wild oat herbicides are applied, Dr Lankford concludes by advising that the best results will be achieved when sprays are made during good growing conditions as this aids uptake. He also recommends the inclusion of non-cereal break crops such as oilseed rape as this gives growers the opportunity to use additional herbicides including propaquizafop, quizalofop, cycloxydim, clethodim and propyzamide. FG

Trials data shows impressive yield advantage for fungicide

Trials for Univoq, the new cereal fungicide from Corteva Agriscience, have suggested it delivers an average yield bene t of 0.25t/ha over its nearest competitor.

Across 36 sites in England and Scotland, Univoq outperformed the previous market standard in more than 80% of trials, with the uplift in yield calculated to be worth around £50/ha to growers.

Mike Ashworth, Corteva cereal fungicide category manager, said: “2021 was a high disease pressure year, and we know that Univoq’s major strength is septoria control, so it gave the fungicide the chance to really show what it is capable of.

“We have seen this excellent yield response from Univoq for many years, so this is not a surprise, but the data presented from last year’s harvest shows a clear advantage which can be directly linked to a greater return on a grower’s investment.” The trials work compared Univoq applied at 1.25-litres/ha to its nearest competitor applied at 1-litre/ ha – rates which Corteva says are comparable in terms of the cost to a grower.

In six of the 36 trials, the competitor product delivered a higher yield than Univoq, but at all other sites, Univoq came out on top, Corteva claims. In two cases, Univoq out-yielded its rival by more than 1t/ha. Overall, the mean di erence between the two products was 0.25t/ha.

Mr Ashworth said: “Growers want reliable, robust chemistry which controls key diseases in order to maintain green leaf area, allowing the crop to ful l its yield potential. When the disease came in 2021, Univoq delivered.

“A 0.25t/ha yield advantage is worth £50/ha to a grower when the wheat price is at £200/t.”

Univoq was launched last year. Targeted at the T2 fungicide timing, it delivers a powerful combination of curative and persistent protection against septoria, plus a broad spectrum of other diseases, including rusts.

Containing the Inatreq active molecule and the patented i-Q4 formulation, Univoq has a unique site of action, meaning there is no cross resistance to any other chemistry used on farms today. A standard application at the T2 timing is 1.25-litres/ha, but rates can be adjusted up to 1.5-litres/ ha or down to 1.1-litres/ha depending on variety and disease prevalence. FG