The government has decided not to re-authorise the use of the pesticide Vydate in a development slammed as 'unacceptable' by the NFU.
The pesticide, manufactured by Corteva Agriscience, can no longer be sold, distributed or used in the United Kingdom.
The storage and disposal of the product has been approved until the 28 February 2021.
Vydate is seen as an important tool for growers of sugar beet, potatoes, onions, carrots and other field veg to control pests on their crop.
The NFU said it was 'urgently engaging' with Defra to discuss the development and the practicalities of its disposal plan.
The union's vice president Tom Bradshaw said: “It is extremely disappointing that Vydate will not be re-authorised by the UK government.
"It is unacceptable the announcement was made just one week before the authorisation ended, with no time for growers to prepare."
Mr Bradshaw said the NFU had 'serious concerns' about the prospects of the industry being able to dispose of the product by the end of February.
He pointed to a lack of notice and relatively short window for the manufacturer to arrange collection as reasons.
“Vydate is an effective and affordable part of many growers integrated pest management plans and we are supporting emergency authorisation applications submitted by industry," he added.
“We will continue to review this decision in greater depth and further analyse what impact this decision will have on farm businesses.”