Arable farming needs to change in order to halt declines in biodiversity and prevent one of the worst mass extinction events in history, a leading US entomologist has warned.

Bold action is required by farmers to stop habitat loss and the unintended consequences of pesticide use having a devastating effect on insect communities, says Jonathan Lundgren of the Ecdysis Foundation and Blue Dasher Farm. 

Highlighting that 60% of insect biomass had already been lost, the award-winning former US Department of Agriculture (USDA) scientist blamed the non-target effects of widely used systemic insecticides, such as neonicotinoids, for some of that damage.

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Pollinator loss

“Constant, low-level exposure to neurotoxins is having implications for non-target species. We are losing pollinators, insect predators and natural enemies because these products don’t stay put,” he says.

“We are finding them in places that they don’t belong. Burying your head in the sand is not OK anymore,” Dr Lundgren adds.

Central to this urgent situation is how the world is producing food, says the scientist, who stresses that agriculture has become too simplified.

“The rise of monoculture means that just four plant species are being grown across vast swathes of America. That’s not good for agriculture or the wider environment,” he says.

In the US, some 97 different pest chemistries are found in beehives today and Dr Lundgren points out that given the presence of neonicotinoids in the countryside, it begs the question as to whether conservation strips are helping or hurting our pollinators.

Next-generation pesticides

Dr Lundgren has similar concerns about the next generation of pesticides, known as RNAi insecticides, which work by blocking or silencing genes on a known insect genome. Although they are being marketed as very specific, he urges greater assessment of their risk.

“It’s not known whether they will silence the correct gene or an unintentional one. If it works on another part of the genome, could it also accidentally bind to genes in non-target species?”

He acknowledges that RNAi technology is not new and has been important in gene therapy.

“But it hasn’t been manipulated before. Tests have shown that 101 pesticidal development RNAi products all had exact matches in bees, although none of them were targeting bees,” he adds.

Farming solution

The solution, which can be provided by farming, is diversity. “We need to change agriculture. Farmers need to be able to produce nutrient-dense food profitably – there are too many third parties making money out of agriculture,” he says.

Dr Lundgren sees regenerative agriculture as a way of making this change. Reducing soil disturbance and increasing diversity will break the reliance on pesticides and raise profits – as it brings soil health benefits and attracts natural enemies.

“Pesticides are replaced by diversity. Yields are lower, by as much as 27%, but regenerative farms are twice as profitable. They also spend far less on seeds and fertilisers,” he adds.

As to why it isn’t already mainstream, Dr Lundgren explains that paradigm shifts take time. “Change is hard. Until now, the science hadn’t been done to help farmers make the transition.”

His advice to growers who want to change is to start small and develop their markets. “It won’t happen overnight but it will change your life. Transformational change always happens from the bottom up.”

• Jonathan Lundgren was speaking at a recent BASE-UK meeting. BASE stands for Biology Agriculture Soil & Environment and is a member organisation that promotes conservation agriculture.