One of the dangers of leaving a lot of rubbish lying about the garden is that it harbours slugs that will attack your lettuce, so that is an argument in favour of a clean garden, with suitable rubbish put in its proper place––the compost heap––and unsuitable stuff burned.
One area we have improved our knowledge and practice is in an understanding of the ecology. Whilst rubbish left everywhere around will increase our pest and disease problems being too neat and tidy means nowhere for the beneficial insects and mammals like the hedgehog to over-winter.
By leaving a few piles of twiggy material around you help provide the good guys with lodgings until the bad guys appear next season.
Cabbage white butterflies are pests of the first order. It is bad enough to have to cope with our own native butterflies, but we also have to deal with the lot that fly over from the Continent every year. They come first in the spring and early summer, and leave us their eggs before they die.
The eggs are laid on all kinds of cabbage crops, sometimes on stocks, nasturtiums and other plants. They are yellow, oval and pointed at one end. You will find the eggs in batches of 20 to 100; in about a fortnight they hatch out into young caterpillars that swarm together.
You can tell them by their colour––bluish or greenish black, with a yellow line down the back and yellow sides. Their hairs are rather straggly. In about a month they are fed up––with your cabbages––and creep away to turn into chrysalides.
About three weeks later, at the end of July or beginning of August, out come the butterflies which lay their eggs, and you get the second and more dangerous lot of caterpillars that do harm in August and September.
The Cabbage White Butterfly has a pal––the small white butterfly that is responsible for the velvety green caterpillars. This butterfly lays her eggs one at a time and not in groups like the “Cabbage White.” There is only one thing to do with any sort of caterpillar: pick them off and squash them. And squash any eggs you can find as well. It is a messy business, but it is worth it.