Time-delayed insecticide

Time-delayed insecticide ‘crystals’ could revolutionise pest management in agriculture following a deal between researchers from Rothamsted Research, New South Wales Department of Primary Industries (NSWDPI) in Australia and the Italian chemical company Endura.

The agreement will allow Endura to commercialise technology that involves the encapsulation of insecticide into tiny crystals.

The technology has proved nearly 100 per cent effective in some insecticide-resistance hot-spots around the world.

Once released onto the market, the technology will allow farmers to destroy pests that are currently devastating crops such as potatoes, sugar beet and cotton.

The formal issuing of a licence to Endura is a result of ten years of research by Dr Graham Moores from Rothamsted Research and Dr Robin Gunning from NSWDPI, who together developed the new encapsulation technology.

A major problem in pest control is the propensity for insects to mutate and become resistant to pesticides by developing enzymes that block insecticides and stop them from working.

The encapsulation works by delaying the release of insecticides to give enzyme inhibitors within the formulation time to disable the enzymes that insects use to block traditional pesticides.

The enzyme inhibitor is referred to as a ‘synergist’.

While many potential synergists exist, most are too toxic for use in agriculture.

So Dr Moores and Dr Gunning’s first task was to identify a naturally occurring synergist, which they did - piperonyl butoxide (PBO).

However, they found that when the synergist was used in a simple mixture with an insecticide it was not effective in restoring the ability of the insecticide to kill resistant pests.

Dr Moores explained: 'We discovered the answer lay in the time taken for PBO to cross the cuticle into the insects and inhibit the enzyme - typically five hours.

'So the insecticide was already blocked by the insect's enzymes before PBO had a chance to act.

'One possibility would be for crops to be sprayed twice, first with PBO and five hours later with an insecticide.

'However, time and cost means that this is not practical, so we had to go back to the lab to come up with a novel, viable solution.'

That is just what they did, developing time-delayed insecticides using a microencapsulation that takes five hours to dissolve and can be applied to crops at the same time as PBO.

Endura has bought the rights to develop the encapsulation technology to bring it to the market for commercial use.

Dr Cosimo Franco, managing director of Endura Fine Chemicals, said: 'With this licence agreement, Endura hopes to promote the wide-spread use of PBO in agriculture.

'It has been shown that the use of PBO contributes to solving the problem of resistance in crops, but it also allows the use of smaller quantities of pesticides, thus reducing the environmental impact.'

A magnified image showing the microencapsulation of insecticide into a crystalline structure