Oak with a problem..??

These Knapper Galls or Oak Apples are caused by the Gall wasp which lays her eggs,which then hatch out into a grub, which then alters the cell division and causes the plant to produce gall tissues that enclose the grubs

These grubs feed on a nutritious layer within the galls before pupating and in turn, turn into adult wasps.

They cause no harm to the oak tree.
Sorry cannot identify, little caterpiller though.

Hope this helps.

Kandy

 

The Gall Wasp lava (Biorhiza pallida) lives inside the gall until mature then it turns into a small wasp so your wee catapillar isn't anything to do with the gall and they cause no harm to the tree. Oaks are a thiving community of parasites and predators, including birds and squirels and have a very rich wildlife dependant on them.

English Country Garden: English Oak, Quercus robur

 

I have seen loads of these on local oak trees this year! I was going to post a picture to see what they were. I haven't noticed them before, so must be a good year for gall wasps.

 

...and some galls just keep getting bigger and bigger. This is a massive gall on a 500 year old oak in Hatfield Forest. I often wonder how many years ago that a tiny wasp first caused this to grow

 

Hornbeam: That looks more like a burr than an oak apple. They can form naturally or sometimes where a trunk or branch has suffered injury. A large burr can be very valuable timber for marquetry veneers or cabinet work.

 

Dunno :confused: - the National Trust's guidebook states:

"Looking up into the tree's branches you can see a large gall. This is a tumour-like swelling probably caused by an insect. These insects make the tree produce this unusual growth to protect their larvae. This is one of the biggest galls in the country."

 

OK - I'll take the NT's word on it. Never seen a gall that size before :eek:

 

For what its worth, I think its a burr as well.
Oak apples seem to occur on the ends of the branches and drop off at the end of the season.
I dont doubt that it was caused originally by some insect years ago attacking the growing point and forming a strange growth pattern, but I dont think its the same as an oak apple.
Its a bit different to most burrs though, in that its not formed at the base of the tree.