What's it look like?
You'll probably notice a pretty white butterfly flitting around the garden this month. Don't be fooled, these are enemies of a great garden. It's the larvae (or caterpillars) of these flitting creatures that chew the leaves of developing plants especially those from the cabbage family.

What it attacks
Cabbage white butterfly will attack any plant in the cabbage family. This includes cabbages, broccoli, brussel sprouts and cauliflower.

What to do before it arrives
Plant out strong smelling herbs like sage, coriander and dill to deter the butterflies. This stops them laying their eggs on the leaves.

The butterflies are quite territorial and won't approach where another has been, so fool them by tying a piece of fishing line over your crop and dangle home made butterflies made from white cardboard covered with contact for rain protection. Don't forget to put a little grey dot on each wing to give it that "authentic" look. This is a great activity to do with the kids and it gets them interested in gardening.

What to do if you already have problems
Always check on the underside of the leaf for little eggs and caterpillars. You will often prevent damage by acting early, before they have a chance to do too much to your plants. Try hosing them off or simply squash them on the leaf. If you leave some "evidence" on the leaf it can deter other butterflies from leaving any unwanted deposits.

You can always do nothing and wait for predators. Last year I squashed a few on the leaf and left them. Within only a couple of weeks I saw lots of predatory wasps preying on unsuspecting caterpillars. After that there was no need to do anything else.

If you cannot live with these critters, then your best organic weapon is DIPEL. This is a biological control that acts on the digestive system of caterpillars. It is totally safe for humans and animals and registered by the organic certification body NASAA (nothing to do with astronauts).

For further information:

Cabbage white butterfly
Cabbage white butterfly. Pieris rapae. Lepidoptera: Pieridae. Characteristics: White, with one (male) or two (female) rounded black spots on dorsal forewing. ... Remarks: The Imported Cabbage Worm Butterfly ("Cabbage White") is the white butterfly seen every day almost everywhere ...
http://darwin.bio.uci.edu/~pjbryant/biodiv/lepidopt/pieridae/cabbagem.htm


Cabbage White Butterfly (Pieris rapae) Picture and Identification
Search. Poll. Grade President Bush on the Environment. A. B. C. D. F. Votes: 8817. Comments: 146. Cabbage White Butterfly (Pieris rapae) Picture and Identification. Butterfly ID Home or Next Butterfly. © 2002 Patricia A. Michaels.
http://greennature.com/article1374.html

CABBAGE WHITE BUTTERFLY
CABBAGE WHITE (Artogeia rapae) ... Flight Period: The cabbage white butterfly is one of the most common ... pest of cabbage and other cole vegetables (Brassicaceae). The cabbage white has continual broods and may ...
http://www.monarchprogram.org/insects/cabbagewhite.htm

BBC - Science & Nature - Wildfacts - Cabbage white butterfly, small white butterfly
Cabbage white butterfly, small white butterfly. Pieris rapae. These butterflies can be seen flying in gardens from July to September. Their small green caterpillars are notorious for their preference of cabbages and their relatives. ... Physical Description. A small white butterfly, occasionally pale yellow ...
http://www.bbc.co.uk/nature/wildfacts/factfiles/398.shtml

Cabbage White Butterfly (Pieris rapae)
... Cabbage White. (Pieris rapae) ... Photos of cabbage white (caterpillar, chrysalis, adult), wing span, identification ... Photo of cabbage white, description, life cycle, active period ...
http://www.nenature.com/CabbageWhite.htm