How biologicals and new approaches are changing pesticide use
© Tim Scrivener Biologicals will make up 25% of the overall crop protection market by 2035, growing by more than three times to a value of $30bn (£24bn), predicts Dr John Wiles, global biology leader with Corteva Agriscience.
Currently, the global figure stands at $9bn (£7.3bn), but the combined drivers of sustainable production, legislation, new modes of action and better efficacy will see that pace of change accelerate.
“They won’t necessarily replace synthetic chemicals, which will be required for the foreseeable future, but they will increasingly be adopted as complementary solutions,” he predicts.
See also: Biopesticides ‘as good as pesticides’ to protect wheat
Derek Oliphant of AgbioInvestor agrees and points out that the market is moving forward rapidly, helped by political initiatives such as the European Green Deal, the UK’s National Action Plan for Sustainable Pesticide Use, and Japan’s Green Food System, to name a few.
“New market growth will all come from biopesticides,” he says. “It’s being driven by regulation, as well as the lack of alternatives.”
The biopesticides market achieved 15% growth in 2022, with products seen as environmentally safe and having low toxicity.
“Concerns about plant extracts and microbials are around stability and shelf-life, not residues or ecosystem collapse.”
There is no doubt that alternative products have a role in integrated control systems and have shown to be effective, especially when their use is knowledge-based, says Professor Neil Havis of Scotland’s Rural College (SRUC).
He cites elicitors – agents or compounds that can induce plant resistance – as a good example.
“They either mimic the action of natural elicitors or mimic signals,” he says.
“Laminarin, which is derived from seaweed, is just one such product – it elicits a response and has anti-fungal activity. It is approved for use in wheat already and should get other crops soon.”
Is there a place for mechanical weeding in winter wheat?
Resistance, regulation and public pressure surrounding herbicide use means that alternative in-crop tools such as mechanical weeding are relevant, says Niab research agronomist Will Smith.
“There are a number of ways to mechanically remove and bury weeds, from pre-sowing cultivations to weed harrowing and inter-row cultivation,” he says.
Inter-row cultivation allows more aggressive cultivation and removes established weeds, so is often carried out in the spring, he explains. As it is spatially selective, crop damage is minimised.
Niab work across four sites using the technique shows that it adds consistency to overall blackgrass control, but that herbicide activity remains important to the end results.
“On its own, it gave 20-25% control of grassweeds, whereas herbicides alone gave an average of 75% control,” reveals Will.
“Those results hide a great deal of variation – in one year, just 5% control was achieved from a £130/ha herbicide programme.
“Combining the two control methods resulted in a small uplift of 10-20%, depending on the season.”
That has led Will to the conclusion that herbicides should be used to do the heavy lifting at the pre-emergence stage, with mechanical weeding used to follow up in the spring.
“We know that most herbicides struggle against blackgrass in the spring, so that’s the time for alternatives.
“Of course, there are unsuitable conditions for hoeing – if you go too early, it can result in root movement and cutting in the crop.”
The cost of inter-row hoeing is about £10/ha/pass, reveals Will, and there’s often a small yield reduction of about 10%.
“A combined system can end up being slightly more expensive at £150/ha, when you factor in the cost of the machine and the labour, but much will depend on the weed pressure.”
His view is that inter-row weeding is one of the solutions that can help farmers hit environmental targets. “It’s about finding the right niche for it and perfecting the technique for grassweed control,” concludes Will.
Trials at SRUC reveal elicitors perform best when combined in programmes with fungicides, allowing fungicide rates to be reduced.
A spring barley trial gave a 0.9t/ha yield benefit from a programme based on an elicitor and reduced fungicide, which cost £39/ha – some £12/ha less than a full fungicide programme.
“There are still things to learn about products like this, including application timing, length of resistance, optimum formulation and compatibility,” says Neil.
Biocontrol is another area of interest, he notes. “This uses naturally occurring micro-organisms, such as bacteria and fungi, to reduce the inoculum or disease caused by a pathogen.”
They work by parasitism and predation of one organism by another, or by antibiotics that are harmful to target pathogens.
They may also provide cross-protection or growth stimulation, he explains.
“Getting the best from any of these innovations comes from using them in a holistic approach.”
What’s happening in Europe?
Strong social and political pressure in Europe to reduce pesticide use has seen the introduction of the EU’s Farm to Fork strategy, which has a target of reducing pesticide use by 50% by 2030.
At the current rate of change, that overall target is expected to be hit, although countries are progressing at different rates – France and Italy are on course, but Germany is behind.
In France, researcher Dr Nicolas Munier-Jolain of Institut National de la Recherche Agronomique (Inrae) is running the DEPHY network of demonstration farms, which was set up in 2010 and involves 3,000 farmers from all cropping sectors – arable, vineyards, orchards, vegetables, ornamentals and tropical crops.
Tasked with reducing pesticide use, these farms are being supported to adopt integrated pest management (IPM) and share their knowledge, with the onus being on individual farms to find solutions that suit their circumstances.
The results have been encouraging, with applications to arable crops coming down by an average of 26%. “This figure hides wide variability across farms, but progress is being made.”
The consequences for productivity and profit have also been investigated, continues Nicolas.
“We’ve seen that using less pesticide has given a slightly lower yield – due to techniques such as delayed drilling, variety choice and less nitrogen – but the resulting fall in costs mean that profits are up.”
Among the most pioneering farmers, pesticides use is down by 40% and productivity is up by 6%, but that has also led to changes in what’s being grown.
“There are less cereals produced but more legumes and grasses.”
The farm context, the management practices used and better decision-making have all been identified as key factors in reducing pesticide use, he adds.
Pesticide reductions in France
- Arable crops -26%
- Vegetables -33%
- Ornamentals -38%
- Tropical crops -18%
- Viticulture -24%
- Orchards -35%
Another project, IPMworks, is a European network of demonstration farms, used to monitor how integrated pest management (IPM) is being adopted and how well it is working.
Again, farmers exchange their knowledge, explains Nicolas, with groups of 10-15 farmers all being supported by an adviser. “This is all about cost-effective IPM strategies.”
All of the article contributors were speaking to Farmers Weekly at this year’s British Crop Production Council congress “Shaping the Future of Crop Protection”, which was held in Harrogate in early November.
