This page has the same theme as the August 11th page, but this time the host is Alder - Alnus glutinosa.
Dull with drizzle.
Two shots of a leaf-miner: Fenusa dohrnii - a sawfly. The larva can clearly be seen near the top of the mine. Reflected light on the left and transmitted light on the right.
There's a lot going on in this picture. Male and female ichneumons, apparently eating a sawfly larva (see below). Female on the left (you can just see the short ovipositor.). S-shaped sawfly larvae can just be made out in the background.
The leaf to the left has also got tiny leaf galls just forming.
Another leaf mine. The larvae belong to a micro-moth - Phyllonorycter rajella. Upperside of the leaf is shown on the right.
These sawfly larvae were decimating many leaves. They start off as in the first picture, about 2 mm long. Then their individual 'tracks' begin to twist and turn (second picture). Eventually, they leave the leaf to pupate (picture 3). Sometimes smaller excavations are found abandoned. Presumably birds or ichneumons or other predators feast on them.
I'm not at all sure what these round marks are. They're either a gall or a fungal attack. Time will tell. Top and bottom shown.
This structure is another fungus - Taphrina tosquinetii. It's very common on Alder, and the raised part (usually at the tip of the leaf) soon goes brown and dies.