Now the black fly's bitterest foe is the lady-bird, but although she makes
all her meals off black or green flies, she cannot cope with all of them.
The black fly usually attacks the top of the plant first, just when it is
beginning to flower, so pinch off the top to check it. The lady-bird won't
But if the black fly spreads despite your efforts末and the
lady-bird's末act as advised at the end of this note, where hints are given
for dealing also with slugs, caterpillars, flea beetles and the cabbage root
fly. But first a word or two about these other pests that may come your way.
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末the compost heap末and unsuitable stuff burned.
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末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末with your cabbages末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.