From the first week of August, wasps and flies can be a great problem with plums and cherries and later on with apples and pears. These insects are particularly interested when fruits are becoming over-ripe. Therefore do not delay in picking the fruits when ripe. Secondly, make sure that local wasps’ nests are dealt with. Wasp traps are only partially effective. Clearing the nests in the vicinity is the best solution.
At garden centres they sell various types of trap, or you can use a simple home-made device. Just take a large jam jar, fill it half-full with a very sweet sugar solution in water, make a hole in the lid and place it near or in the fruit trees. The wasp will enjoy the sugar for the rest of its life. An easy solution of how to catch wasps in the garden.