Biopesticides fill in the gaps in crop protection armoury for soft fruits and vegetables

Roma Gywnn reviews the availability of biopesticides in the UK.

Beauversia bassiana: fungus used on whitefly and thrips. Image: Rob Jackson
Beauversia bassiana: fungus used on whitefly and thrips. Image: Rob Jackson

There is a global drive for good-quality food production using sustainable crop protection. Even with current measures, it is estimated that 30-40 per cent of crops are lost because of pests, diseases and weeds, making it clear that crop protection is an important consideration for assuring food security. Biopesticides can help meet this challenge.

They are effective alternatives to chemical pesticides and, in many cases, using them will not cause residues. They can be used as stand-alone products or as part of integrated pest, disease or weed management programmes. They can help fill some of the crop protection gaps left by withdrawn chemicals and they can be used with chemical pesticides as a resistance management tool.

Biopesticides also have a role in helping growers to meet the requirements of increasingly stringent national and European environmental policies, such as the EU's Sustainable Use Directive and the Water Framework Directive.

What are biopesticides?

There is no standard definition of biopesticides. The Chemicals Regulation Directorate's (CRD) Biopesticides Scheme includes products with active substances based on micro-organisms, botanicals (or natural biochemicals or plant extracts) and semiochemicals (including pheromones).

An additional category of "other" is judged on a case-by-case basis (see box). All products intended to be used for plant protection must be registered, unless exempted by the CRD.

Products based on insect parasitic nematodes may be referred to as biopesticides but they are exempt from registration. However, they are regulated under the Wildlife and Countryside Act (1981) and only species found naturally occurring in the UK can be used.

Biopesticides are regulated under the same European legislation as chemical crop protection substances, which means the active ingredient is registered at EU level and products that contain it are registered in member states.

Production is by large-scale, complex processes that are usually precisely controlled, automated systems producing active ingredients of consistent high quality. For micro-organisms, it is mainly by industrial-scale fermentation.

There are often arguments that biopesticides are simply not as effective as chemicals. In part this may be true, but if a product is registered its effectiveness has been independently tested and the labels reflect the levels of control that can be expected.

Bear in mind that modern crop protection is about proactive population management, using integrated pest, disease and weed management to tip the balance in favour of the crop. Where there is potential for populations to get out of control, the aim is to manage the pest or disease to levels below the threshold where it affects yield and quality. Biopesticides work well in this type of approach where products are used before pests or diseases reach damaging levels. Repeat applications can be integrated with other control measures.

Biopesticide products in the UK

The Horticultural Development Company has recently funded two projects to look at biopesticide availability for soft fruit and field vegetables. The aim was to provide growers with information on biopesticides that could already be used and to consider how more products could be made available in time to address key gaps in their crop protection armoury.

In the USA there are at least 280 biopesticide active substances registered, compared with 77 in the EU and 16 in the UK. So why is the USA so far ahead? One of the key differences is the way in which biopesticides are registered. The USA has had a biopesticide-specific registration system in place for more than 15 years, so registration continues to be more of a hurdle in Europe.

There is also specific Government support for developing biopesticide capacity in the USA, particularly for use on minor crops, through the IR-4 Biopesticide and Organic Support programme.

In the USA, product effectiveness is not a part of registration, unlike in Europe. It is a matter of debate whether this is an advantage and there are clear disadvantages - how else do growers judge whether a new product is effective? - but in Europe testing for efficacy is a compulsory part of registration.

However, the European markets are also highly fragmented compared with North America. The UK on its own is a small market so, just as with chemical pesticides, it may not be economic to support registration for many biopesticide products.

The most obvious gap for all soft fruit and field vegetable crops is that in the UK there is only one bioherbicide. In fact, this is not just an issue specific to the UK because there are few bioherbicides available globally. The low-cost margins for these types of products probably make biopesticide development economically unfeasible. Another important gap is that there are few biopesticides available that control plant-parasitic nematodes.

The limited range of available biopesticides means that currently there are few options for pest and disease control for UK growers. However, several new products are going through the registration process. These include products that are active against fungal and bacterial diseases and insect pests.

Considering the number of biopesticides that are already available elsewhere in Europe - and the fact that US-based biopesticide companies are starting to register more active substances for the EU - it is reasonable to assume that there is potential for biopesticide availability to increase further in the UK, provided manufacturers consider the UK as a viable market that justifies registration costs.

How to improve availability

Strong Government support for biopesticide registration, such as that in the USA, has resulted in registration becoming less of a hurdle to biopesticide availability. Although that system, as it stands, would not fit EU rules, there are still good lessons to be learned.

The UK Biopesticides Scheme is a step in the right direction. Under the new EU rules that come into force mid 2011, there is a clear commitment to provide guidance for biopesticide registration and an opportunity to streamline biopesticide registration and increase availability to growers.

As mainly smalland medium-sized businesses, biopesticide companies that are developing products for sustainable horticulture could benefit from increased Government business support. There are currently some tax incentives to support research, but help is also needed in other areas. For example, biopesticide companies often have limited expertise in registration.

In the Netherlands, a government-supported programme, GENOEG, was set up a few years ago to address the business issues and to increase growers' knowledge and effective use of "natural origin" pesticides.

The aim was to identify effective products, assist registration (including costs of up to EUR100,000) and share knowledge. The fact that more products became available and growers learned more about using them is a mark of the programme's success. A similar approach could help growers here.

To overcome the current hurdle of fragmented markets, it could be worth establishing ways in which growers of crop groups with similar pest or disease problems could collaborate to identify what biopesticide products they need and to link with suppliers to make biopesticides and knowledge about them more widely available.

Chemical pesticides have been in frequent use and the focus of Government-supported implementation research and development for more than 50 years. As relatively new products, there is an urgent need for R&D to support wider use of biopesticides, such as guidance on their specific features, development of use programmes and improvement in knowledge on field delivery, including using existing equipment.

- Dr Roma Gywnn of Biorationale Biopesticide Strategists is speaking at this year's biopesticides conference being held on 21 April in Grantham by the Association of Applied Biologists in conjunction with the International Biocontrol Manufacturers Association. For further information, visit www.aab.org.uk

BIOPESTICIDE PRODUCTS

Based on micro-organisms

These contain bacteria, fungi, viruses, viroids or other microscopic organisms such as protozoa as their active substance. UK examples include Serenade ASO, based on the bacterium Bacillus subtilis, Naturalis-L based on the fungus Beauveria bassiana and the insect virus Cyd-X Extra based on Cydia pomonella granulosis virus.

Based on botanicals, natural biochemicals or plant extracts

Botanical biopesticides contain active ingredients derived from various parts of plants and may also be termed plant extract or natural biochemical products.

They include products based on garlic or plant oils such as thyme or clove, for example, the registered products Barrier-H based on citronella oil and Vacciplant based on the plant extract laminarin.

Semiochemicals

"Semio" comes from the Greek word for signal, hence semiochemicals are the signalling chemicals emitted by plants, animals and other organisms that cause a response in individuals of the same or other species.

The most common examples are insect mating pheromones and the scents that pests home-in on to find their preferred host plants. For example, Exosex CM is a pheromone-based biopesticide registered in the UK for controlling codling moth on apples.

If pheromones or other semiochemicals are used for controlling a pest, they must be registered - but not if they are being used for monitoring populations.

Download below a table of:

REGISTERED BIOPESTICIDE PRODUCTS IN THE UK

EXEMPTED BIOPESTICIDE PRODUCTS IN THE UK (JANUARY 2010)


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