u/trobopoline

Anyone in the utilities sector (UK) know what/why these markings are for? The are relatively recent in yellow chalk, the ones on the pavement are what I'd usually expect to see, but unsure why they've put an X next to my vents? Vaguely recall some workers in hi-vis doing some late night (possibly emergency) investigations last week so assume it may have been them. Any ideas?

Hi everyone, I have two apple trees and a pear tree in my garden. Every year in springtime I get an infestation of these eggs and subsequently small caterpillars. They tend to leave their eggs in any 'wounds' in the bark they can find and I haven't yet found a way to prevent their yearly infestation. Only lay in the apple trees, never the pear. Any help identifying and eradicating would be very helpful. Thanks