How To: Check For a Maggot in Your Apple

An apple maggot, caught at the scene of the crime…

You’ve probably heard this old chestnut: “What’s worse than finding a maggot in your half-eaten apple? Finding half a maggot in your half-eaten apple…”

Here’s a quick guide to avoiding that rather unpleasant eventuality.

Know Your Enemy

Apple maggots, or apple worms, are the larvae of the codling moth[1] (Cydia pomonella). These insect pests emerge from hibernation and fly[2] up into the tree in spring, when the blossom is in full bloom, and then lay their eggs on the leaves and sometimes on new fruitlets as well.

When the eggs hatch out, the emerging larvae tunnel down into the fruitlet, making themselves at home – eating and frassing all over the place – until they reach a suitably full-grown size. They then drop from the apples (if the apples haven’t dropped to the ground already due to the damage done by the maggots) and pupate in the soil, grass or mulch beneath the tree.

A second generation of moths then emerges in July and August. This second generation is the one that damages the maturing fruit, repeating the earlier lifecycle and then over-wintering in the soil or leaf litter, ready to emerge as breeding adults again next spring.

What to Look For

So how can you tell if there’s a nasty little maggot hiding in the depths of that pristine-looking apple before you bite into it? With careful examination of the fruit for the classic warning signs of maggot infestation, that’s how.

Sometimes it’s rather obvious that something has been eating your apples, due to the gaping wounds and/or brown rot that’s already developing around them. Often though, this sort of damage is due to pigeons or squirrels pecking and gnawing at the fruit, with wasps – or slugs, if the fruit drops to the ground – then moving in to enlarge existing holes.

I’m going to stick my neck out and say this is an example of squirrel damage…

Moth damage can be a bit more subtle and harder to spot. Here’s an example of a beautifully ripe and ready ‘Kidd’s Orange Red’ apple:

It looks perfect, doesn’t it? Ready for eating! But wait, what’s this? A tiny mark on the underside, near the ‘eye’ of the fruit:

On closer examination, you can see that it’s definitely a maggot tunnel, with the tell-tale signs of maggot frass (droppings) around the rim:

Hmmm. That doesn’t bode well. But it’s a small hole, so hopefully the damage will be limited. Only one way to know for sure, and that’s to cut the apple open, to see how bad it looks inside:

In this case, I was lucky. There’s only minimal damage there and I can easily get rid of the maggot tunnel[3] and associated frass by quartering and coring the apple and then giving the quarters a good wash. It’s then perfectly good to eat[4].

One other thing to bear in mind: maggot tunnels aren’t always visible on first examination. Sometimes they don’t tunnel through the flesh of the apple if they can just get in through the ‘eye’ – the remains of the blossom, at the opposite end of the fruit to the stalk. Some apple varieties have particularly open, wide or deep eye basins, so it’s possible that a maggot could tunnel in through the ‘eye’ and not leave a clearly visible trail.

All of which explains why it’s a really good idea to closely examine an apple for the tiniest amount of damage before you chomp away, and ideally cut it in half to be absolutely sure. This is especially true when picking your own from an Organically managed tree that hasn’t been sprayed with pesticides.

Badly-damaged apples can still be (partially) eaten, of course. It’s important to cut away all damaged areas and wash the remaining pieces of fruit thoroughly to clean them up as much as possible. And it’s a good idea to cook with them, just to be doubly safe and sure. I’ve been making plenty of spiced apple compote from windfall apples this year and have filled up a tray in my freezer with packets of fruit that will keep my porridge interesting all winter long[5].

How about you? Do you have a sure-fire method for detecting codling moth damage? Do you know of any reliable, Organic codling moth controls (pheromone traps excepted, as discussed above)? Do let me know, via the comments section below.


1 Presumably ‘codling’ is a derivation of ‘codlin’, an old name for a group of apples suitable for cooking in sub-boiling-point water – a process known as coddling, often now only applied to eggs – that’s preserved to this day in the names of heritage varieties like ‘Keswick Codlin‘.
2 Which is why grease bands offer no protection against them whatsoever. Pheromone traps are often recommended but are really more of an indicator than an eradicator; they catch some of the male moths, which then lets you know they’re active, at which point you can spray your trees with insecticide if you’re not Organically inclined.
3 I knew it was definitely a maggot because I caught the horrible thing half in and half out when I picked the apple off the tree. Needless to say it was squished, pronto.
4 It was delicious, too; ‘Kidd’s Orange Red’ is by far my favourite dessert variety in the Plot #79 orchard.
5 Lashings of custard may also be involved at some point.

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