UK farmers worry that the new rules could cut yields
The National Farmers Union says that a proposed EU ban on pesticides could lead to the price of British fruit and vegetables doubling or even trebling.
The EU wants to ban farmers from using a wide range of chemicals which it says are dangerous to human health.
But the NFU says they are valuable tools in the fight against disease and pests and the ban would be "absurd".
The environment secretary said the ban would have "a damaging impact for no discernable benefit for human health".
On Wednesday, European MPs will vote on the second reading of new pesticide legislation.
The government says that, if they have their way, as many as 85% of chemicals currently used in Britain could be banned.
The EU says it wants "to stimulate the production of more effective pesticides to the benefit of farmers and the chemicals industry, while improving environmental and health protection".
Antonia Mockin, from the European Commission, said: "These are the substances that are most dangerous to human health, that cause cancer, that disrupt the body's internal systems - reproductive and otherwise."
But farmers fear a ban could lead to a disastrous reduction in crop yields and as a result, large increases in food prices.
They say that, without pesticides, they could waste up to four times as much of their crop, meaning that growing it would no longer be viable.
Sarah Pettet, a vegetable farmer in Boston, Lincolnshire, told the BBC: "Broccoli, cauliflower, carrots, onions and a number of other crops could not be grown in this country.
"It would not be possible to produce the quality, healthy fruit and vegetables that we currently produce at the prices that consumers are currently enjoying.
"We would see significant price increases - doubling, tripling - and in some cases, particularly low income families would not be able to afford healthy fruit and vegetables."
Environment Secretary Hilary Benn said the proposal had not been properly thought through.
"The British government has been at forefront in Europe in saying, 'Hang on a minute, we don't think you have got this right.'
"'Have you thought through the consequences - because our own assessment says the ban will have a very damaging impact for no discernable benefit for human health.'"
NFU Deputy President Meurig Raymond said it was "absurd" for the EU "to start banning the very tools which make food production possible".
"Moreover, the absurdity of this proposal is exacerbated by the fact that food produced using the very same sprays to be banned in the EU will still be imported from outside the EU and eaten by us all."
But others believe the EU plans should go even further.
Lord Peter Melchett, from the Soil Association, said: "We think these proposals are a small step in the right direction.
"They could go further and the British government should be pushing for them - not opposing them."
A final vote on the legislation is likely to be held in December or January.