Natural insect repellent to cut pesticide use

Using novel biochemical techniques, British scientists have recreated a natural insect repellent that can help avoid the use of chemical pesticides and save plants from pest attack.

The scientists created tiny molecules which mirror a natural occurring smell known to repel insects.

The team found that the smells repelled insects but in one case a reversal of behaviour - an attractant - was observed which raises the prospect of being able to develop a trap-and-kill device.

"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," said lead researcher Rudolf Allemann, professor at Cardiff University.

"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," Allemann explained.

The scientists were able to make similar smelling insect repellent molecules, by providing the enzyme, ((S)-germacrene D synthase), which creates the smell, with alternative substrate molecules.

The effectiveness of the smell or perfume to function as an insect repellent was tested.

"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," Allemann pointed out.

Pesticides are toxic by design and are used widely to kill, reduce or repel insects, weeds, rodents, fungi or other organisms that can threaten public health and the economy.

The study appeared in the journal Chemical Communications.