Today's Courrier de l'Ouest had as its main story dire warnings about a new critter, not native to Europe that is decimating sweet chestnut plantations in France. Big news guys - the wee varmint has been here for a year or two, and specifically in the One Acre Wood.
Last spring we spotted galls on some of the low branches of some of the young sweet chestnut stems, and wondered what it was about. Now we know - Cynips de Chataignier - or Dryocosmus Kuriphilus - or Chestnut Gall Wasp.
Self-fertile (nasty) wasps lay eggs in next year's leaf buds in the summer. The following spring, the eggs hatch in the bud and create a gall in which they live and feed and grow. They hatch out in late spring/early summer and fly around laying more eggs. The effect on sweet chestnut trees is to reduce fruiting drastically - by up to 70% some claim - as well as sapping the strength of the branch their gall is on, and in the long term, reducing the strength of the tree.
It is a notifiable pest, so that is today's job, finding and reporting it to the relevant authority and waiting to hear what happens next.
If you spot galls on sweet chestnut trees, check them against this website/document and then contact your local authority with responsibility for control of foreign pests.