Some caterpillar species are serious plant pests – the cabbage white butterfly, for instance, can devastate brassica crops. Many plant-eating caterpillars are the larvae of moths.
There are innumerable different species of caterpillar. So many different shapes, sizes, colours and textures, that there is no such thing as ‘your average caterpillar’.
Many are species of moth – which tend to be small, green, well camouflaged and often hide away among the plant, and only tend to come out at night to feed. These can be very difficult to spot
And not all of them are particularly harmful - yes they will eat through fruit, leaves, flowers, stems and even roots but one day the very hungry, creepy crawly before you may become a beautiful butterfly.
Most caterpillars will either completely eat the plant parts or leave them more-or-less completely skeletonised. They often leave behind black or dark brown faeces.
Treatment and Control
Try picking them off the leaves (as they often feed at night a torch might come in handy) and removing them to a site where any damage will be less harmful. If this is not possible, then the answer is to spray with a suitable insecticide. For best results, spray at the first sign of infestation.