Following reports of a potentially counterfeited pesticide being imported into the UK, the manufacturer of the product in question has urged caution and called for "cross border co-operation" to address the issue if foul play is uncovered.

An illegal imitation of post-emergence grass herbicide propaquizafop (trade name Falcon) may have been supplied to a UK grower. An arable farmer registered concern after being supplied with a replacement herbicide product by his buying group, which gave off a 'solvent-like' smell up on opening.  

Propaquizafop may be used in oilseed rape, swedes, turnips, linseed, combining peas, field beans, potatoes, sugar beet, fodder beet, carrots, parsnips, bulb onions and for forestry purposes. According to the NFU, the illegal pesticide was supplied as an alternative to Falcon under a different name.

Makhteshim-Agan UK, which manufactures branded off-patent products, including Falcon, announced on Thursday that "counterfeit and illegal plant protection products remain a problem in mainland Europe and to a lesser extent in the UK." The company's regulatory manager Anne Fletcher described the alleged illegal importation as an "international trade issue [which] requires cross border co-operation among competent authorities and companies" to ensure no harm comes to crops, users or the environment.

She said, "Parallel imports of existing registered products are, of course, perfectly legal in business terms but they must be imported only under the terms of a parallel trade permit obtained in accordance with the law from the relevant department of the UK's Health and Safety Executive."

Ms Fletcher continued, "What is not legal or legitimate business is the import of plant protection products not covered by a genuine parallel trade permit. Illegal products are often of dubious origin, poorly formulated or manufactured, may be incorrectly labelled and are potentially dangerous to the farmer or the environment. Illegal products may also contain little or no active ingredient or even banned substances."

The herbicide at the centre of this week's intrigue has been sent for laboratory analysis and reported to the UK authorities.

In a warning last year, EU crime intelligence agency Europol said organised criminals have been attracted to the exceptionally "low risk – high profit" margin of the counterfeit pesticide market. Although the agency said North-Eastern Europe in particular has been targeted by the criminal networks involved in the supply of illegal and counterfeit products, Europol spokesperson said, "Criminals have developed complex global supply chains and exploit legal companies to camouflage their activities" all over Europe.

In May 2011, two multi-tonne shipments of illegal pesticides intercepted in Eastern Europe were found to contain substances banned in the EU for their endocrine disruptive properties.

Farmers suspicious of a product they have been supplied with should contact the Defra helpline on 08459 335577