Cabbage white caterpillars must be controlled or you will lose your crop
These can be a real problem, and if you are growing the brassicas where you eat the leaves they can destroy your crop, and the growth of the hearts of cauliflowers and the sprouts can be severely affected. If the infestation is really bad they can completely destroy the leaves which means that the plant cannot photosynthesise and therefore will not put on any more growth.
You can be really vigilant and pick the caterpillars off by hand, but you’ll have do this a couple of times a day; or you can put a fine insect-proof mesh over the whole lot, making sure you bring it down the sides of the crop.
We have placed twigs at each corner of the raised bed and a larger one in the centre to suspend the mesh over the crop. The mesh has been weighted down at regular intervals with stones. Make sure there are no gaps around the edge as the butterfly will almost certainly find them.