Company representative Robert Hesse said: "It turns itself on half an hour after dark. The light fluctuations disorient the insects and they fall into the basin below and drown, so you have caught them at the flying stage, before they lay their eggs."
A single unit, costing just under £400, can control pests in a 2ha area, while a smaller unit, at around £170, is designed for glasshouse use. "You might pay £1,000 per hectare per month to spray against pests," said Hesse. "This will pay for itself in a year, and lasts five or six."
In China, where the traps are made, they are mandatory on state farms, he added.