Cabbage Butterfly

The cabbage moths are now out in full force. I love the way they look fluttering around the garden but their caterpillars feed gregariously and can wipe out crops incredibly quickly!  There are two types of white cabbage butterfly (or moth), the cabbage butterfly (Plutella xylostella) and the small butterfly white moth (Pieris rapae). It is the small white butterfly that causes the problem here in our vegetable gardens. It is native to Europe, North Africa and Asia, being first recorded in Victoria in 1937. It has one of the longest seasons of any butterfly emerging from the crystalis in early spring and remaining active until mid-winter. The cylindrical green larvae (the caterpillars) are a major pest of Brassica crops (broccoli, cabbages, cauliflower, kale etc). Their colour allows for very good camouflage. They spend 17-21 days munching on  your vegies before pupating for 8 days or so. They are tasty to predators so they like to keep to the underside of the leaves to avoid being spotted.

As their name implies, White Cabbage Moths are white in colour , though the undersides range from white to pale yellow and are often speckled with black. Individuals often have black upper wingtips, and females have a black dot in the centre of their upper wing. They are very strong flyers, and though they rarely range more than 6km or so, it is estimated that they can fly over 160km over their lifespan. When they were first introduced to Australia, they spread from Melbourne all the way to Western Australia, in only 3 years.

They are tricky to eradicate naturally because of their marvellous camouflage and their sheer numbers but there are a few things worth trying.

Removal by Hand

Hunting and picking off the caterpillars is time consuming but very worthwhile. Buy some butterfly nets, give them to the kids and let them go wild.

Territorial Bluff

White Cabbage Butterflies are territorial so putting things in the garden that look like their opposition can be effective. Cutting out butterflies from white plastic and stringing them around the garden, placing eggshells around the garden, and planting white flowering plants such as white geraniums and white petunias, can make them think that your garden already has a white butterfly population and they go elsewhere (we hope!!)

Nasturtiums

White Cabbage Butterflies love nasturtiums. Plant some around your vegie garden and it will attract the females away from your vegetables crop. Nasturtiums are such vigorous growers over the warmer months that there will be more than enough to go around.

Natural sprays

There are some natural, organic sprays on the market or you can make your own. You must ensure you reach the underside of the leaves.