Consumers Demand Less Pesticides

Scientists Respond with a million pound study which will re-bug the system with an army of friendly insects

There is a war being waged in the countryside, which will use an army of environmentally friendly insects to eliminate the use of pesticides. If the battle is won it will ensure that consumers, retailers and wildlife will benefit from reduced pesticides in the food chain.

Those nasty beasties that voraciously gobble up crops are creating more of a problem for beleaguered farmers and according to scientists at The Game Conservancy Trust these destructive pests, such as aphids, orange wheat blossom midge and gout fly could become more prevalent due to global warming and the loss over recent decades of habitat that encourages friendly insects.

But using pesticides to control these pests has a negative environmental impact on water catchments and biodiversity, and increasingly, consumers and retailers are demanding produce that is completely chemical-free.

Now a new £1 million scientific study has just been launched, which aims to investigate the best way of boosting friendly insect numbers in crops in a bid to reduce pesticides. It will also look at the socio-economic constraints limiting adoption of biocontrol in this country, and to define a framework to improve the broad-scale uptake of environmentally-friendly pest control with a view to eventually replacing pesticide usage in the food chain.

This new million pound collaborative study is being undertaken by three leading research institutions including The Game Conservancy Trust, Rothamsted Research, and Imperial College. The project called 'Rebugging the system' is being funded by a new Defra/Research Council funding initiative called RELU (Rural Economy and Land Use).

Part of this important study will investigate ways of reducing the use of chemicals to control crop pests by utilising the services of beneficial insects such as beetles, spiders and hoverflies – a process known as biocontrol. Entomologists from The Game Conservancy Trust, a Hampshire based wildlife research charity, will be carrying out one of this country's largest field studies to determine how much land needs to be devoted to habitat that encourages environmentally-friendly insects, such as beetle banks, conservation headlands, wildflower margins and grassy field banks.

Dr John Holland, head of entomology with the Trust said, "We are trying to measure the amount of insect rich habitat that is needed to produce an effect. No-one has investigated it on this scale before and our aim is to see how much land needs to be manipulated to create good habitat before you encourage beneficial insects sufficiently to achieve natural pest control."

The Game Conservancy Trust has been researching farmland ecology for nearly 40 years. It was the first organisation to firmly establish the link between the intensification of agriculture, particularly the use of herbicides, and the sudden declines of farmland birds and gamebirds such as the grey partridge. Having identified the problem the Trust developed conservation headlands and beetle banks to restore plants and beneficial insects.

The Game Conservancy Trust's field trials will start in Spring 2005. Initially the Trust is interested in getting a range of farms in southern England to participate in the scheme – from just a few fields to whole estates. The project aims to utilise the prescriptions included in Government Agri-environment schemes and will focus on the addition of six metre flower-rich mixed-grass strips at field margins, which are known to be attractive to both predators and parasitoids.

The approach to habitat manipulation will be to examine insect response starting at single fields containing grass strip margins, up to an extensive area-wide landscape scale manipulation, containing a central field with grass strips and surrounded on all sides by fields with grass strips up to three fields deep. This part of the project could involve whole estates measuring up to 400 hectares in size.

Monitoring will take place on four replica areas selected for each scale as well as on four control fields with standard field margins.

Within each field to be monitored, the impact of ground and crop active predators and parasitoids (parasitic wasps, hoverflies and predatory beetles) on cereal aphids, will be measured using a specially designed exclusion technique. Each area will be infested with a fixed number of cereal aphids in late May. Cereal aphid numbers will be monitored when predation by ground active predators is most important. The monitoring will identify the contribution that each natural enemy type makes to cereal aphid control and to what extent this is influenced by the scale of habitat manipulations.

John Holland explains, "We have over 500 different species of insects and spiders living in cereal fields. Only 10 of these species are a problem to our crops, but their effect can be devastating. The aim of this experiment is to find out how we can harness the beneficial effects of predatory insects by creating the right habitat conditions so that they can thrive and wage war on harmful pests within cereal crops. We just need to identify how much good habitat is needed to boost the populations of predatory insects enough to get the right effect."

The Game Conservancy Trust is currently looking for farms and estates in southern England that would like to participate in this new project.