Posted: 30/12/2014 at 10:37
They pretty much already said it: biological warfare. Nematodes.
- The number of annual generations varies from one to four according to the climate (varying with latitude and altitude), the year, and sometimes the host plant.
... so they'll show up at all sorts of times, depending where you live.
More quoted material:
The natural enemies of the codling moth include birds, spiders, insects, nematodes, bacteria, fungi, protozoa, and viruses (Falcon & Huber, 1991). Natural enemies are most effective in reducing codling moth population at three times during its life cycle: egg stage, newly hatched larvae, and the wintering larvae (MacLellan, 1969).
The great tit, Parus major Linnaeus, was considered by Massee (1954) the most important species of bird attacking codling moth larvae in Britain. This species, along with the blue tits, Parus caeruleus Linnaeus, was also found to be the most important by Solomon et al.(1976) in different unsprayed apple orchards in Europe.
In Britain and Nova Scotia (Canada), heteropterans seem to be the most important codling moth predators (MacLellan, 1962, 1963; Glen, 1975).
... plus earwigs, but they wreck the fruit too.
Then you get to the parasitoids, little tiny wasps whose babies go all H.R.Giger Alien on the moth larvae. There's a beauty of an example called the emerald wasp who's the best friend of anyone with a cockroach phobia.
A few good bird boxes (the kind made from a 240x30x2cm plank, not the "2mm plywood and panel pins" things some bird food companies sell) and a load of well-stocked feeders could encourage some dedicated predators to come visiting every day, as long as you're not spraying poisons all over the place.
Failing all that, you could always try burning cigars around the trees ...