Leaf Miners

[David Humphries]

Here's what we believe is oak leaf miner, called Rhynchaenus quercus

Unlike the Chestnut leaf miner (Cameraria ohridellha) its not a moth but a weevil.

 

Not sure I've noticed such a heavy infestation on our oaks here in London before, perhaps a milder winter?

 

Any one else noticing this on oaks around the country?

 

 

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[David Humphries]

The grub lives, feeds & deposits between the upper & lower leaf surface & is approximately 5-7mm in length.

 

 

The round galls to the left of the weevil grub in the last shot are not associated but probably small oak pea galls of the gall wasp Cynips divisa

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[David Humphries]

Haven't come across the emergent adult weevil before but here's what it looks like.....

 

 

 

 

picture taken from Claude Schott's website Entomologie en Alsace

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[dexta]

I hope this is not going to become a problem like it has on the horse chestnut . There is a row of horse chestnut here and at the moment they look fine but given a while all the leafs will going the same way. Some have been removed but I don't no how much longer the others have or if they can continue with this.

[David Humphries]

Shouldn't really be a problem as they're indigenous with their associated predators keeping their mortality level in check.

 

(where as Cameraria doesn't have the same level of associated predation (yet)

 

I imagine that as long as the infestations are not as bad as this year each year, then it shouldn't have an major effect on the host vitality (by itself) too much.

 

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[armybloke]

Nice photographic evidence and diary David. I will keep my eyes peeled and report back. I saw something similar on Hornbeam on Wednesday and was looking for evidence of the little critters! I will go back sometime next week as it is local and see what I can find.

[Adam M]

Not noticed any leaf miners but have seen a few pea galls this year.

[jomoco]

Good stuff David, very educational.

 

Jomoco

[David Humphries]

The Holly leaf miner - Phytomyza ilicis

 

larvae becomes a small black fly (not seen that....yet)

 

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[David Humphries]

The Holly leaf miner - Phytomyza ilicis

 

looking a little closer, my glamorous laboratory assistant informs me that there appears to be perhaps other bugs at work.

 

The holly leaf miner suposedly only lays one egg per leaf so these small doughnuted circles are perhaps the larvae of another leaf miner or gall insect?

 

 

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