Codling moth larva, the maggot in the apple, about to crawl out after the damage is done, but what triggers its emergence?
The ‘Grenadier’ apple had hit the ground with a thud, I stood it on my orchard seat and as I watched the larva appeared. Out of curiosity, I touched it on the nose, or at least where the nose would be if it had one, and it retreated back into its hole and didn’t come out again whilst I was watching. I wonder if the thud of the apple hitting the ground triggers a ‘bail out’ response. It would have survival value for the larva to get clear of the apple as soon as it fell and into cover for hibernation, before the fruit was eaten by foraging animals.
Barry Potter
Codling moth larva: final emergence
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Very interesting! Given that Codling Moth also has a tendency to make infected fruit drop early, this would appear to be a very cunning trick to enable the larva to get away!
I wonder if you can do a controlled experiment: carefully pick a larva-infested apple, then drop it and see if the larva crawls out? The classic reason for keeping livestock in the orchard was to eat the larva-infested drops; if they escape before being eaten, I guess this would defeat the strategy.
Great photos! I have been following blogs on apple and pear pests and diseases for about eighteen months now as part of a research project and have seen a series of photos and this question discussed before although I know of no conclusive result.
I include the Royal Horticultural Society page on the subject in case it is of any use but am inclined to think that Kevin’s solution is the best idea. It would be interesting to see if anyone contributes to say that they have few or no problems with larvae and keep poultry too!
This is the RHS page: click here