Damage to garden plants
The caterpillars of moths eat the foliage or other parts of plants. In gardens they may be feeding on edible plants, ornamental plants or ‘weeds’. In most cases this is minor damage to leaves and can be tolerated, as the it has a very limited effect plant vigour and appearance. Growing healthy, large or more vigorous plants can minimise this impact and make it more acceptable.
Although the majority of the 2,500 UK moth species do not cause noticeable damage in gardens and should be encouraged, and handful are considered problematic, including; codling moth, holm oak leaf-mining moths, horse chestnut leaf-mining moth, leek moth, pea moth, plum moth, winter moth and tortrix moths. Cabbage caterpillars may be those of moths or, more commonly, butterflies.
If damage is not tolerable then try to use natural enemies to control caterpillars by encouraging predators such as ground beetles and birds in the garden. You can also employ hand picking and biological control methods. If you wish to use pesticides, contact action and short-persistence pesticides will have lesss impact on non-target insects.