Swarms of greenflies have been causing a nuisance for several days - but why the sudden invasion?

Large concentrations of the sap-sucking pests have been ruining garden plants and spoiling people’s enjoyment of the warm weather.

We spoke to the Yorkshire Wildlife Trust’s Jono Leadley to find out why there are so many greenflies and when they are likely to be gone.

Jono says the warm weather conditions have combined to cause the sudden proliferation of greenflies as well as rapid plant growth.

“Greenfly respond to plant growth. Plants are their food and greenfly can respond without having to mate.

Greenfly making themselves at home on a rose in Mirfield this week

“Female greenflies can reproduce without having to mate and the population can increase five times in a week.”

The current crop of greenfly are ‘homegrown’, rather than an invasion from abroad, he added.

Jono believes a big rise in ladybirds - a natural predator of aphids like greenflies - may soon follow.

“The greenfly issue may be relatively short-lived and could be followed by large numbers of ladybirds.”

Dr Gordon Port, from Newcastle University’s School of Natural Environmental Sciences, says greenflies usually hitch a ride on the wind but lights winds has meant they are not being dispersed.

Dr Port says we will continue to notice greenflies until the wind is strong enough to disperse them.

“In average weather conditions they get blown away quickly, but when it’s relatively still and warm, like this, we tend to notice them.”