Re: My apple tree is in blossom.
Emjay, I have found this for you. It is Wyevale advice.
It says about using Provado Fruit & Bug spray.
Could be impossible if it is a huge tree though, I imagine.
"Control has to be preventative, rather than a ‘treatment’, as once codling moth are in amongst the fruit, there’s very little you can do. To prevent coddling moths, we recommend the following:
Set up pheromone traps, such as Growing Success Apple maggot monitoring trap. These you simply hang from the tree in March-May. They emit a smell replicating that of a female virgin moth, and male moths fly in looking for fun. Once inside, they get trapped on a sticky sheet at the bottom of the box. This, whilst not being a complete solution, does at least reduce numbers of breeding moths.
Target with and insecticide spray, which contains deltamethrin, such as
Provado (Fruit & Vegetable) bug killer. Try to avoid spraying flowering trees though, as you may kill the beneficial pollinators. The best time is after blossoming - around mid-June - and again 3 weeks later. Unfortuantely, spraying isn't very suitable for larger trees.
As the weather cools, ensure you make your garden a haven for wild birds, as they'll seek out tasty caterpillar cocoons in the winter.
Try wrapping ridged cardboard around the trunk of the tree from late June. This may help catch a few caterpillars moving around the base of the tree to pupate. They'll use the cardboard as a place to pupate, instead of a tree crevice, meaning you can simply lift it (and them) off and destroy or burn."