When monitoring for Loopers, the first thing David Williams does when he walks into a block is have a look at the trees.
“If I can see insect dropping on leaves and a few chewed leaves, I stand still and quiet, letting only my peripheral vision watch for movement. You’re a threat to the Loopers so they stay still and watch you, but if you can stay still long enough then they will start moving again and that’s when you spot them.”
Further Reading:
Apple looper: pest of apples and grapevines https://www.agric.wa.gov.au/pome-fruit/apple-looper-pest-apples-and-grapevines
Article Reviewed by David Williams (Agriculture Victoria)