This slimey critter skeletonises the leaves of pear, cherry, plum and quince trees. A big infestation can really thwart the growth of young trees. Its the larvae of the sawfly, and turns up each summer on its chosen victims.
To control it, you can 'find and squish' regularly on a small tree (although its a particularly gruesome and icky task - WEAR GLOVES). Ash or lime thrown onto the leaves also can help. Or if desperate, a squirt of pyrethrum insecticide, carefully targeted so as not to kill beneficial insects, will kill the bastards. You may need to repeat your control measures several times during the summer season. Good Luck!
