As Dave Chandler, principal research fellow at Warwick Crop Centre reveals, “in the past we considered chemical controls as silver bullets for pest control – but those days have gone”. While producers seek alternatives to chemical forms of crop protection, a new project from UK research and development body AHDB Horticulture named Amber is helping growers work more confidently with biopesticides
At a time of year when amber-hued leaves of all shapes and sizes are brightening up our landscapes, it is certainly fitting that the aptly named Amber project is now in full swing after its launch this summer. Amber – which stands for Application and Management of Biopesticides for Efficacy and Reliability – is a five-year project that is testing a range of registered biopesticide products on six different horticulture crops, including: capsicum, mint, cucumbers, cyclamen, chrysanthemums and hardy nursery stock.
Crop protection “at a juncture”
As those fresh produce buyers who have their own sustainability programmes will recognise, biopesticides are being used more frequently by growers as part of their integrated pest management (IPM) programmes. These IPM crop protection regimes are included in Europe’s mandatory Sustainable Use Directive (SUD), which stipulates that: “biological, physical and other non-chemical controls must be preferred to chemical methods if they provide satisfactory pest control.”
Chandler asserts that, even when the UK leaves the European Union, British food producers will still be practising IPM regimes because “food standards are becoming increasingly globalised.” However, because biopesticides – which include semio-chemicals (such as pheromones), micro-organisms (beneficial fungi, bacteria, and viruses), and botanicals (plant extracts such as citronella oil) – are relatively new to the market, some growers are understandably wary of them.
“They are less efficacious than chemical pesticides – they tend to be less robust,” says Chandler, who believes that biopesticides can play an important function if used collectively with other forms of crop protection. He concisely describes the horticulture industry’s position as being “at a juncture”, emphasising the importance of developing better management practices to improve biopesticide performance and therefore grower confidence and uptake. “Right now it’s like the 1980s, when parasitoids were first being used in glasshouses,” he says. “We need to do a similar kind of study.”
Sharing information for future protection
The Amber team – which (in addition to Chandler) includes specialists from Warwick Crop Centre, Adas, Silsoe Spray Applications Unit (SSAU), IPM specialists Rob Jacobson and Roma Gwynn, and industry steering group chairman Paul Sopp – is therefore working closely with commercial growers to find out how to get the most out of some of the key biopesticides that are now on the marketplace.
“It’s important that we are able to use them effectively and get the best out of them,” stresses Chandler. “Agchem and biocontrol companies are developing these kind of products – and they have a lot of information on them – but that’s no substitute for things getting in the hands of growers and developing and improving them within their own systems. And that’s what this project is about.”
Helpfully, Amber is targeting a range of the industry’s most problematic and economically significant pests and diseases – that is, those that are notoriously difficult for growers to control and that damage the quality of their crops. These include: aphids, western flower thrips, glasshouse whitefly, and two-spotted spider mite – as well botrytis, powdery mildew, downy mildew and phythium. Moreover, the crops in the project have been chosen for their differing plant architecture to give researchers a clearer understanding of how the products work on, and can be applied to, various plant species.
Spider mite: notoriously difficult for growers to control
Given that all growers are often tackling the same problems, the information that’s being acquired throughout the course of the Amber project will be shared with producers of other types of crops, such as tomatoes. “The results will be released throughout the lifetime of the project,” says Chandler. He also notes that Amber has so far had some interesting results. It has found, for example, that “some products don’t mix at all – they don’t go into suspension [disperse in water]. We need to improve the preparation/mixing of biopesticides in a spray tank”.
Developing new best practice guidelines
The results of Amber will clearly be much needed by the fresh produce and wider horticulture industry, particularly as, reveals Chandler, “pest management is becoming more challenging.” He points out, for example, that the injudicious use of conventional chemical products has resulted in “nearly 600 pests in the world” developing resistance to insecticides. Moreover, this surge of pesticide resistance could have wider implications. Chandler notes, for instance, that: “There’s rising concern about the effect of some fungal pathogens on human health. It’s a growing problem and it’s becoming harder to tackle because they are developing fungicide resistance. It’s going to place further pressure on fungicide use – more than we already have.” He adds that, amidst widespread concern about the risk that chemical pesticides such as endocrine disruptors pose to our health and the environment, the number of active ingredients (conventional pesticide substances) approved by the EU has shrunk from nearly 1,000 in 1998 to less than 400 today.
Perhaps unsurprisingly – and largely because of the SUD – biopesticides hold the strongest place in Europe’s market. “Within five to 10 years, there will be more biopesticides on the market than chemical pesticides,” says Chandler. This is perhaps welcome news for fresh produce buyers because biopesticides are low-risk products that offer many benefits to those who source, pack and transport fruits and vegetables. These include the fact that some of these products do not leave behind any chemical residues on crops – and the fact that they can have a low re-entry level, which means that the crops can be harvested shortly after they’ve been treated.
With these benefits in mind, the best practice guidelines that are being developed as a result of this five-year research project will undoubtedly form a key part the industry’s current and future sustainability programmes.
Dave Chandler was speaking at the British Tomato Growers’ Association’ conference in Kenilworth in September.
