ACORNS & MARBLE GALLS

If you see a young oak with spherical nut-type things on, these are not acorns, nor are they oak apples.  They are marble galls caused by a tiny gall wasp laying eggs on the shoots. 

 In autumn they turn brown as the female insects emerge 

and fly to find a turkey oak to lay eggs on.

But there are plenty of acorns this year too.

 

You may also notice oak powdery mildew, a fungal presence which can slow down growth of the tree if it spreads too much.  It is very common and develops in warm, dry overcast conditions.