Scientists from Cardiff University and Rothamsted Research Institute believe they may be able to help agriculture move beyond pesticide use. Researchers have developed a scent to repel insects, as part of a drive to create greener alternatives to agricultural chemicals.  

The scientists said their ‘natural’ method of repelling insects is a world first. Though the molecules they managed to create mirror a scent known to repel insects, the team said that earlier efforts to create an effective natural pest repellent have run into difficulties.

Professor Rudolf Allemann who led the research at Cardiff, explained, "We know that many organisms use smell to interact with members of the same species and to locate hosts of food or to avoid attack from parasites. However, the difficulty is that scientifically smell molecules are often extremely volatile, chemically unstable and expensive to re-create. This means that, until now, progress has been extremely slow in recreating smells that are similar to the original."

The scientists worked to create a more stable molecule than the original, but which still has a similar scent to the natural smell molecules. they managed to achieve this and tested their new molecule.

Prof Allemann said, "Through the power of novel biochemical techniques we have been able to make insect repellent smell molecules which are structurally different but functionally similar to the original."

The team found that the smells they developed repelled insects in most cases. However, they observed the opposite effect in one trial - insects were attracted to the smell. Unperturbed, the researchers said this too could be put to use, in developing trap-and-kill devices.

The work was carried out in response to growing concerns over the effects traditional pesticides are having on the environment, either through harming non-target wildlife, damaging ecosystems, or endangering human health. Experts have said there is a need for a nuanced approach to crop protection, which attempts to defend crops, whilst recognising the fragility and importance of species that form part of a functioning ecosystem.

The team hope that their research findings could pave the way towards new means of designing and developing small smell molecules which would be otherwise be too difficult to produce by usual scientific and commercial methods.