What kinds of Cabbage white butterflies are there in Australia?

In Australia, there are two primary species of cabbage white butterflies that are commonly found in vegetable gardens. These butterflies lay eggs on plants in the Brassicaceae family, such as cabbage, broccoli, and cauliflower. The caterpillars that hatch feed on the leaves, causing significant damage and reduced crop yield. Here are the two species of cabbage white butterflies found in Australia and their visual descriptions:

1. Small cabbage white butterfly (Pieris rapae)

The small cabbage white butterfly has a wingspan of 32-47 mm. The upper side of the wings is white, with black tips on the forewings. Females have two black spots on each forewing, while males have only one. The undersides of the wings are pale yellowish-green with faint black spots, which provide camouflage when the butterfly is at rest.

2. Large cabbage white butterfly (Pieris brassicae)

The large cabbage white butterfly has a wingspan of 50-70 mm. The upper side of the wings is predominantly white, with black tips on the forewings and a black patch on the front edge of the hindwings. Females have two black spots on each forewing, while males lack these spots. The undersides of the wings are pale yellowish-green, similar to the small cabbage white butterfly, but with more pronounced markings.

Control measures for cabbage white butterflies:

1. Monitoring: Regularly inspect your plants for eggs, caterpillars, or signs of feeding damage. Early detection allows you to implement control measures before the infestation becomes severe.

2. Physical control: Handpick caterpillars from affected plants and dispose of them. You can also remove and destroy any leaves containing eggs.

3. Exclusion: Use floating row covers to prevent adult butterflies from laying eggs on your plants. Ensure the covers are secured tightly around the edges to prevent butterflies from entering.

4. Biological control: Encourage natural predators, such as birds, wasps, and predatory insects, by providing a diverse garden habitat with shelter, water, and food sources.

5. Chemical control: If caterpillar populations are high and causing significant damage, you can apply Bacillus thuringiensis (Bt), a natural bacterium, to target caterpillars. Always follow the label instructions and apply Bt when caterpillars are small for the best results.

By understanding the different species of cabbage white butterflies in Australia and their visual characteristics, you can better target your pest control efforts and maintain a healthy vegetable garden.