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Apple sawfly

Posted: Wednesday 10 October 2012
by Richard Jones

I view our raggedy apple tree as a wildlife resource, as it supports lots of interesting apple-eating creatures, including apple sawfly.


Apple with a scar caused by a sawfly larva

As usual, our raggedy apple tree has produced a meagre crop of pretty raggedy apples. I try not to let this weigh on me. Instead, I view the tree as a wildlife resource, as it supports lots of interesting apple-eating creatures, including blackbirds, wasps, codling moth… and this year apple sawfly.

Hoplocampa testudinea is a small, secretive, furtive beast. At only 6-7 mm long, it is easy to overlook, and its dull black and straw-yellow colours hardly advertise its presence. Distantly (very distantly indeed) related to bees and wasps, sawflies get their name from the female’s saw-toothed egg-laying tube. This is used to cut a slit into the tissue of an appropriate plant, which then provides a food source for the larvae. In this case, the female cuts a slice into a nascent apple bud, into which she lays an egg. 

The larva then chews a tunnel just under the skin of the developing fruit, which falls, prematurely, in June. A larva may make its way through, or over, several buds, before finally falling too inside a final fruit.

Occasionally, the initial chewing to a bud is not quite enough to destroy it, or cause its fall, and the fruit continues to develop, albeit damaged. The resulting apple is distorted, and scarred with a brownish girdle.

The apples on our tree are barely edible anyway, being rather bland and tasteless. I cook with them, so I simply remove any holes, dimples, scabs, tunnels, warts and blemishes - even girdles - before they go into the pie.





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happymarion 10/10/2012 at 16:04

Doesn't it make life interesting when your plants are less than perfect? A bit like people, I guess.

happymarion 10/10/2012 at 16:04

Doesn't it make life interesting when your plants are less than perfect? A bit like people, I guess.

Colin Richards2 24/10/2012 at 09:27

I have suffered much less this year from the dreaded saw fly we had more frost than usual last two winters has helped but my apple tree (Red Devil) has suffered from some tunnelling insect that seems to be coming from the core of the apple. Any ideas on how to prevent this as they get into every apple. Colin