By Sarah Mukherjee
BBC environment correspondent
Science is trying to devise new ways to defeat crops pests
Scientists say they are worried about new EU proposals which could drastically restrict the number of pesticides available to farmers.
The registration process is changing and many commonly used chemicals are likely to fall out of use.
It is claimed the replacement regime could lead to reduced yields and further increases in food costs.
But anti-pesticide campaigners say the changes are needed to help protect human health and the environment.
Agro-science is in a constant battle against the pests that attack our food crops. Like the Indian plant-hopper, these tiny unwanted animals can strip a field completely, literally sucking the life out of the plants.
The plant-hoppers are studied under strict quarantine conditions at centres such as the UK's Rothamsted Research Institute. The insects are resistant to the latest generation of pesticides - and we are beginning to run out of solutions to use against them.
"It can take 10 years to develop a new pesticide," says Dr Steve Foster.
"Because of the legal, and health and safety, hoops you have to go through, it can also cost hundreds of millions of pounds," he told BBC News.
Dr Foster and many other scientists working in this area say they are appalled at new proposals coming from the European Union, and in particular from the EU Parliament, which are likely to result in the removal from use of many of the most effective pesticides.
The row centres on a rather obscure sounding directive called 91/414. This directive ceases this year, and a new regime needs to be put in place.
Two things are happening. First, the registration process for pesticides has been so slow, many are still not on the approved list under the current directive.
As the directive runs out, chemicals may be lost to farmers because, in effect, they run out of time, and fall off the end of the list.
Secondly, members of the European Parliament want to get much stricter regulations into the new replacement regime. One agro-chemist told me: "Everybody's jaws fell to the floor once we realised the implications, which appear not to have been based on science at all."
A report by the UK government's own Pesticide Safety Directive points out that no impact assessment has been carried out for the proposals.
Anti-pesticide campaigners say the proposals are long overdue
It goes on to say: "The [European] Commission proposals could remove up to 15% of the substances assessed, some of which are particularly important in the UK for protection of minor crops such as carrots and parsnips.
"It is possible that the endocrine disruptor criteria could impact particularly on fungicide availability and might result in 20-30% yield losses in cereals.
"The Parliament proposals include a single approval period for candidates for substitution of five years and could result in the loss of up to 85% of conventional chemical substances after that period.
"If the full potential impact of the current Parliament proposals were realised, conventional commercial agriculture in the UK (and much of the EC) as it is currently practised would not be achievable, with major impacts on crop yield and food quality."
Dr Bill Parker, an entomologist with the agricultural consultancy Adas, sums up the concerns that he and the farmers he works with have about the new regime.
"If you start to reduce the number of tools in the armoury - not just for pests but for weeds and diseases as well - then that actually makes the business of food production much more risky," he told BBC News.
"It doesn't necessarily mean we are going to have food shortages overnight, but in due course and in certain years we could well end up in the situation where the harvest for one particular type of crop in one particular year could be very severely compromised."
But anti-pesticide campaigners say the new proposals are much needed, and it is vital that the EU recognises the importance of bringing in measures to protect the environment and human health.
Georgina Downs, from UK Pesticides Campaign, says the new measures "must not be watered down by industry lobbying".
Ms Downs argues that people regularly or repeatedly exposed to, or working with, pesticides may have a higher risk of incidence of cancer or other chronic diseases, birth defects, and many other complaints.
She says chronic health impairment results from a low but constant level of pesticides and has a long-term character; and clear correlations between exposure and chronic effects are not often recognised immediately since no obvious symptoms of poisoning exist.
Bur farmers warn that without all the available tools, they will find it increasingly difficult to maintain productivity - particularly in the face of rising food demand.