Written evidence from Professor Toby Bruce, Keele University (INS0014)

I am an Entomologist with 26 years’ experience specialising in plant-insect interactions and chemical ecology. My research focusses in particular on insect pests of crops.

1. Solely blaming pesticides, such as neonicotinoids, for insect decline is too simplistic an explanation. Evidence supports a combination of causes[1] including habitat loss, loss of foraging resources and other explanations in addition to the use of pesticides. Mechanical weeding on organic farms can also reduce biodiversity.
2. It is true that insecticides are designed to kill insects and are often broad-spectrum meaning that they kill non-target insects in addition to the pest targets. Their use should be minimised to avoid these off-target effects that can harm pollinators or natural enemies of pests. Overuse of insecticides can also lead to development of insecticide resistance in the target pest species.
3. High yielding crop varieties from the “Green Revolution” in the 20th century, that more than doubled global food production[2], were developed as part of a package that included fertilisers and pesticides. The high yields are often dependent on high levels of pesticide inputs and if these are not available there is a risk of yield decline and reduced food security, in the UK and globally. Even with pesticide use, it is estimated, by the FAO and CABI, that approximately one-third of global harvests are lost to pests, weeds and diseases[3].
4. In 2019, I made a My Science Inquiry pitch to the Commons STC[4]. I highlighted the lack of tools in the toolkit for crop protection and the risk to food security this represents. Currently the pace which crop protection products are being lost, either due legislative restrictions or to evolution of resistance, is much faster than the pace at which new interventions are invented and brought to market.
5. If policymakers don’t allow conventional pesticides anymore, because of biodiversity concerns, then there is a need to develop alternatives and to make them available to farmers. Crop losses to pests will go up if there is a move to pesticide free farming unless some new interventions are developed…
6. Although there is a highly polarised debate between nature conservation groups and agriculturalists regarding conventional pesticides, there is common ground in that both sides of the debate agree that development of new solutions would help to solve the problem. Farmers would prefer not to use pesticides if they didn’t have to.
7. An excellent example of what can be done was the development of orange wheat blossom midge resistant wheat[5]. Wheat varieties with the midge resistance don’t need insecticide treatment, which is just as well because the main product that used to be used (chlorpyrifos formulated as ‘Dursban’) has now been banned. There has been excellent uptake of midge resistant wheat varieties by farmers and they represent approximately half the UK wheat area. Midge resistant wheat was developed as part of the HGCA-Defra sustainable arable LINK programme (which no longer exists).
8. Development of new approaches to crop protection requires increased investment into research and development. Discovering how to protect crops from pest insect attack while conserving other insects is not trivial and cannot be left to nature. The natural situation is for pests to eat the crop when there is an abundance of a crop species in a field. There has been a steep decline in research funding for applied research focussing on improving crop protection from Defra, which is paradoxical because the need for new approaches is becoming increasingly urgent. The BBSRC is the strongest supporter of agricultural research but tends to focus on more basic research.
9. More benign approaches to crop protection could be made more available if there was reform of the regulatory system for plant protection products. The regulatory system makes little distinction between conventional toxic chemicals and greener alternatives such as semiochemicals, plant defence activators or biopesticides. The high cost and exceedingly long time taken for obtaining regulatory approval means the regulatory system is dysfunctional and is actually a barrier to innovation.

27 April 2023