In message , alan_m
writes

How to make a Greenfly trap

Decide that the garden is a good place to paint an item (a door)

Paint the item a nice shade of snow white

Lean item against the fence to dry in the sun

Check item 15 minutes later to find that approx 100 Geenfly have their
legs struck in the now drying paint! Luckily its not too bad as once
the (undercoat/primer) paint is fully dry the fies could be wiped off
with a damp cloth.
Huh! Try spraying a car outdoors in Summer with cellulose paint....


--
Tim Lamb