Fusarium is biggest challenge for onion sector – The Vegetable Farmer

The onion market is highly affected by global production volumes and quality, and Andy Richardson of Allium & Brassica Agronomy presented the latest production figures from this year’s British Onions Crop Survey. These suggest a total area of just under 8,000ha, the lowest figure in the UK for 30 years, with reds accounting for just under 30 per cent of production. “The set area was down about 20 per cent and the brown spring-drilled area was down about six percent, but red spring drilled area was down around 11 per cent,” he said.

“The packers among you will know that at the minute red onions look like they will be desperately short.” Together these factors suggest a similar UK crop to last year at 362,740 tonnes-above 2018’s low level of 322,100 tonnes but well below the 500,000 tonnes grown in 2011 and the ten-year average of 430,000 tonnes.

“All in all, it’s been a pretty challenging season from a growing perspective,” Andy added. As a result, we have seen imports from Spain, the Netherlands, Egypt and Poland, although China, Chile and India have also supplied crop so far this year. “The forecast is that we will bring in over 350,000 tonnes by the end of this year, so we are importing as many onions as we are growing here in the UK.”

Andy also addressed the quality of stored crops, adding that early assessments suggest we could see high levels of Fusarium and bacterial rots, as well as thick and dried-back necks, all of which could combine to make more than 11 per cent of the stored crop unmarketable. Combined with continued cost pressure and climate change, the future of onion production in the UK remains challenging. “As some point we need to adapt our systems and infrastructure, but with every obstacle comes an opportunity,” he concluded.

Ron Spans, sales manager at Dutch set producer Broer BV added a European perspective to the production figures. “Rather than challenging, I would say it has been a horrible, stressful season, but l don’t want to be too pessimistic,” he began. Unlike the UK, most countries in Europe saw an increase in area (except for red varieties where seed availability was an issue), but many areas also suffered similar weather challenges with late sowings, drought, heavy rain and flooding, all of which have raised concerns about the quality of crops.

In the Netherlands crop availability is currently limited due to high prices, which are also limiting export demand which is down 17 per cent on average so far this year. Despite this Ron said that imports to the UK so far have been higher than average, although packers and shippers are seeing more quality issues than normal.

While economics are probably the main factor which determines how many onions are grown, agronomic factors and the risks of producing a high-quality crop are also important. Chris Bettinson of Elsoms Seeds stressed the work undertaken by their partners Bejo and De Groot En Slot on improving the quality of onion varieties, as well as how dedicated set producers such as Broer BV and the English Set Company work to provide quality sets for growers. “We are producing new varieties which you can grow, and which fit your criteria in terms of storage, yield and disease resistance,” he said.

One of the biggest issues facing onion growers across Europe is Fusarium, and Emma Garfield of G’s Growers explained how the industry is putting together a programme to tackle the issue. “In a post-AHDB scenario this is a real illustration of how industry can get together to keep this really essential research going,” she explained. Through the BOPA R&D committee proposals have been put together for a Fusarium Early Diagnostic & Management (FUSED) project, which brings together a range of industry stakeholders including growers, packers, agronomists, research organisations and technology providers.

“From discussion with the BOPA R&D membership we know that losses [from Fusarium] have now increased from 10 to 40 per cent,” she explained. “Scaled up that equates to a figure of £10million, so we are talking about significant losses on top of the cost inflation that we are seeing and that has contributed to the contraction of the onion area that we have seen.” The BOPA-led proposal has been combined with a parallel funding bid from agri-tech company B-hive Innovation, and it is hoped that a two-year project can deliver soil diagnostics and improved agronomy techniques, as well as computer vision and volatile detection technologies to detect infected bulbs at harvest and in store.

As well as the FUSED project, Emma stressed that more work is required to understand Fusarium and provide growers with effective controls. “We are still looking to that Holy Grail of varietal resistance,” Emma added. “Ultimately, it’s a long-term solution that we need to get to. My understanding is that the onion genome is enormous and there is still some fundamental work to be done. We also need to understand the pathways of infection and the fundamental biology that will enable breeders to develop those traits that we need.”

The BOPA R&D committee is one example of how the horticultural sector is working together following the demise of AHDB in the industry, and Horticultural Crop Protection (HCP) Ltd is another. Part-time CEO Simon Conway provided an overview of how the grower-owned, subscription-based organisation is working to deliver EAMUs and Emergency Approvals for minor crops.

He explained HCP is effectively looking after 31 crop associations, with a team of four full time crop scientists, plus a team co-ordinator and himself as CEO. “We are trying to keep things as lean as possible,” Simon explained. “We needed to keep [the transition] seamless as at any one time this team is producing 70-75 percent of all the EAMUs and Emergency Applications for horticulture each year.” HCP has developed a good working relationship with CRD and now occupies ‘a confidential middle ground’ between the industry and the pesticide approvals process.

In terms of alliums, key targets that the industry has identified include downy mildew (where there is both pathogen resistance and a lack of active ingredients) and bean seed fly where there is currently no alternative to Force ST (which is currently subject to an application for an Emergency Approval). In addition, CRD is currently evaluating five EAMU applications for bulb onions with a further three potential candidates identified.

However, while HCP has been largely successful in keeping the application process for EMAU sand Emergency Authorisations for existing pesticides going, Simon sounded a note of caution about the future, particularly where residue studies, efficacy and crop safety trials are required to support applications. “Some of the other costs are quite significant and for the crop associations it has been quite a wake-up call,” he said.

Pointing to the success of the AHDB SCEPTRE and SCEPTRE plus projects at identifying potential candidates for future EMAUs, he warned that there is currently no equivalent: “There is a danger that we could become a sticking plaster, in that we are always looking at next season’s EAMUs that we have data for, but what do you do when you start running out of data? You have to start looking at not only annual contributions to run HCP, but also a fighting fund. It’s quite a significant cost.

“Another issue is that many crop protection companies are not currently registering new actives due to uncertainty about how CRD will deal with applications and the delayed publication of the Government’s Pesticide Action Plan which Simon said, “desperately needs to be published.”

Herbicides are just one area affected by a lack of approved products, but Angus Hill of VCS Agronomy (UK) Ltd explained how the company has been trialling the ARA precision sprayer from Ecorobotix on onions and other crops with very promising results.

Described as combining spot sprayer technology with high outputs, the ARA sprayer offers the accuracy to spray a 6x6cm target but with work rates between two and four hectares per hour working at speeds of up to 7.5 km/hr.

Angus explained that the current ARA uses six camera units and 156 nozzles across three sections to provide a six-metre working width. “We have seen a slight yield benefit, which may be due to the lack of phytotoxic effects on the crop, and the fact that the unit is fully hooded reduces drift and may allow you spray more of the time,” he added.

The way the software works also means that it can be switched from weed identification (for herbicide use) to crop identification (in order to apply fungicides or insecticides). Wit more than160 machines sold worldwide over the last two years, and orders already coming in for 2024, Angus added; “It has been extremely reliable and straight out of the factory this machine offers a lot of potential. It can also be used for other activities, such as band spraying.”