You will need
454g Tin of Black Treacle
1Kg Brown Sugar, (the darker the better)
500ml Brown Ale (for the moths not you!)
Slowly heat the ale in a large pan and simmer for five minutes.
Stir in and dissolve the sugar, followed by the treacle and then
simmer for two minutes. Allow to cool before decanting into a container.
Fizzy drinks like Cola
or Irn Bru may be used in place of the ale. A drop of rum stirred
in just before use is recommended but not essential. Paint the mixture
at eye level onto 10-20 tree trunks or fence posts just before dusk
and check for moths by torch-light for the first two hours of darkness.
You should make sure you have the owners permission for this activity.