The Cabbage White Butterfly

DISAPPOINTED TO SEE YOUR CABBAGE AND KALE DECIMATED?  Blame the caterpillar of the CABBAGE WHITE BUTTERFLY. It is probably the most widespread pest of the KITCHEN GARDEN.

Read all about them in this Fact Sheet from ABC Gardening Australia

The problem with being on holiday in springtime is that I am thinking about the garden the whole time – if you didn’t know it by now I am telling you, gardeners are obsessive!  I don’t know if you have noticed but gardeners never sit in their gardens – they are always doing something.  

No sooner do I sit down with a cup of tea and the paper and I am up; pulling out that weed, marvelling at something that has just begun to flower, harvesting beans that need picking and pulling off caterpillars.

In fact, that was the first thing I did when I returned from my holiday to Malaysia – walked out into the garden and did a health inspection, because, after all – early intervention often saves a whole crop of food.  The rest of the garden can wait; deadheading flowers, pruning shrubs, weeding, mulching, mowing – unimportant compared with my food plants.  Mostly everything looked pretty healthy apart from these!

Caterpillar of the cabbage white butterfly

WHAT: I only had to look at my kale plants to see that they were being devastated by the caterpillar of the cabbage white butterfly.  Tell-tale holes, munching of the new growth, and it didn’t take long before I spotted those well-fed green culprits camouflaged along the mid-rib of the leaves.

WHO: The adult cabbage white butterfly (c.w.b.) is a small creamy/white butterfly with a black spot on each wing  and it is only interested in plants in the brassica (cabbage) family – hence its name CABBAGE white butterfly.  This is where an understanding of vegetable families and companion planting is going to make you a better gardener.

HOW:  The cabbage white butterfly is not attracted to any plant that is not in the brassica family.  So what do smart gardeners do?  They interplant with those from another family because the c.w.b. will leave those alone. They may be so confused that they don’t even settle on your brassica plants and fly off to someone else’s garden where they have conveniently planted their cabbages in neat rows!!  (Does nature ever do that?)

What do you notice about the beetroot leaves in the above photo – not one munch hole – that is because beetroot is in a different family, CHENOPODIACEAE– it is not a BRASSICA so the c.w.b. will leave it alone.  In fact most of the plants in this family are pretty pest free – this is a good reason to interplant them among your brassicas – it helps confuse the c.w.b., assists with passive crop rotation (they take different things out of the soil) and means that you always have something to eat.  Let’s start with these two families and watch the whole companion planting story unfold from here!

BRASSICACEAE:  cabbage, broccoli, kale, radish, cauliflower, Brussels sprouts, rocket, swede, turnip, bok choy, chum soy, mustard greens.  (You will notice that the stronger smelling and hairiest of these almost never get attacked by the c.w.b. i.e. mustard greens, radish and rocket)

CHENOPODIACEAE:  beetroot, spinach, silver beet, chard, sorrel, amaranth, quinoa.

BEING CABBAGES.  Students at a workshop in Bali role playing the cabbage white butterfly and companion planting story. Who said gardening was boring?

CONTROL OF THE CABBAGE WHITE BUTTERFLY:

•  Try fooling the butterfly by placing pieces of eggshell  around the garden (the theory is that they will think that there is already a butterfly there and fly off).
• Interplant with lots of strong smelling herbs like basil, fennel, parsley, dill and tall flowers like cosmos, zinnia and marigolds – this creates confusion to the c.w.b.  When they flower they have the added benefit of encouraging beneficial insects that wants to do a lot of the work for you.  Do this first – don’t reach for the spray can because you will be killing off the goodies too!
• Make your garden a safe haven for their natural predators – birds and lizards – and don’t keep domestic pets that will scare them off.  I have an opportunist magpie that follows me around the garden waiting for me to pick off any caterpillars I find.  Provide areas of ground-hugging shrubbery and lots of shallow bird baths to encourage them.
• Last resort-spray with Dipel. This is a bacillus that only affects the gut of caterpillars and is safe to use for organic gardeners.

MOST GARDEN PEST CONTROL IS UNNECESSARY – some cause more problems than they solve – be patient – let’s grow things, not kill them.

Holiday reading – gardening magazines! Gardeners are never off-duty.

For a complete list of FOOD PLANTS and their FAMILIES click here

Homemade vegetable oil spray for scale and other sap-suckers.

Homemade fruit fly baits