Contradictory EU policies first encouraged and then undermined the farming of oilseed rape in Europe, according to a new analysis involving a team of Rothamsted Research scientists.

Their report confirms that climate change polices initially rewarded the widespread planting of rape – the world’s most important vegetable oil after soybean – but subsequent pesticide laws have ultimately led to very large yield losses across the continent in recent years.

This collapse of oilseed rape farming in the UK and Europe had led to a reliance on imported oils – including palm oil, the growing of which is often responsible for tropical deforestation, and oilseed rape from countries still using pesticides banned by the EU.

Poor EU policies

The report’s lead author is Dr. Patricia Ortega-Ramos from Rothamsted Research. She said the series of EU policy decisions essentially “created a serious crop pest”, adding:

“This is a great example of how a better understanding of pests and joined up decision-making are going to be vital if we are to reform farming.

“The EU’S 2009 Sustainable Use of Pesticides Directive was not well implemented, and as a result of that and subsequent decisions, the cabbage stem flea beetle has now become a serious pest,” she added.

The researcher added that the area of oilseed rape being grown is now falling sharply, with huge financial consequences for farmers and major environmental consequences.

“It is imperative that smarter pest management becomes written into new EU and UK policies,” Dr. Ortega-Ramos continued.

“We also need to help science develop the tools required by farmers to fight pests without the associated environmental costs, and to find ways to include and incentivise farmers to help develop and use these new methods.”

Oilseed rape

Published in the journal, GCB-Bioenergy, the Rothamsted case study reviews why, in the early 2000s, the EU introduced a series of policies and market-based incentives to encourage the production of biofuels in order to meet obligations to reduce greenhouse gas (GHG) emissions.

After the EU implemented these pro-biofuel policies, the area of oilseed rape harvested increased by 78% between 2003 and 2010, achieving a record harvested area of 6.4 million hectares in 2010.

Oilseed rape is the second largest source of vegetable oil globally, and the most important biofuel feedstock in the EU.

However, this huge increase in the area of oilseed rape grown across Europe, reduced both the variety of other crops grown, and the amount of natural habitat on farms.

These led to population booms of the cabbage stem flea beetle and another pest, the pollen beetle, which both feed on the plant. To fight back, farmers increased their use of pesticides, especially neonicotinoids.

EU policies on pesticide use

In an attempt to curtail excessive pesticide use, the EU’s response was the 2009 Sustainable Use of Pesticides Directive.

But the uneven, and often poor, implementation by member states ultimately led the EU to ban outright the use of neonicotinoids four years later, over concerns it was harming bee populations.

The ban led to increased use of another type of pesticide, pyrethroid, which inevitably led to pesticide resistance arising in the beetles.

With no way to control them, widespread crop failures and significant yield losses for farmers have become commonplace. Since 2018 the area of oilseed rape grown in Europe has collapsed to 2006 levels.

Palm oil importation

As a direct result of this decline in the area of oilseed rape being grown, and in order to meet the EU transport targets, imports of palm oil used for biodiesel reached an all-time high in 2020.

Palm oil plantations are often cited as a major cause of deforestation in the tropics.

Dr. Ortega-Ramos said: “It is clear now that the contradictory, even if well-intentioned, policy initiatives led to the development of a serious pest.

“Perhaps, if the EU’s sustainable pesticide plans had been put into law at the same time as the drive to meet the biofuel target, then the biofuel target would have been reached without relying on imports, and insecticide resistant beetle populations might not be so widespread.

“However, there was a lag in implementation and slow behavioural change in the use of insecticides over that timeframe which allowed the beetle to ‘escape’,” she added.

Co-author of the report, Dr. Sam Cook, who leads Rothamsted’s integrated pest management research, said reliance on insecticides for crop protection is unsustainable.

He added that a broad range of management options are required for farmers to be able to combat pest in a sustainable and efficient way.

“Integrated pest management offers a set of tools that can help suppress pest damage and discern when, and what, control methods are required, reducing unnecessary insecticide inputs and minimising environmental damage,” he said.