|Small White caterpillar|
Small white butterfly
The Small White is a small- to medium-sized butterfly species of the Yellows-and-Whites family Pieridae. It is also commonly known as the Small Cabbage White and in New Zealand simply as white butterfly. The names "Cabbage Butterfly" and "Cabbage White" can also refer to the Large White. It is widespread across Europe, North Africa and Asia and has also been accidentally introduced to North America, Australia and New Zealand where they have become pests on cultivated cabbages and other mustard family crops.
Attacks are worst during hot, dry summers, but the risk period is any time from April to October. Inspect the underside of leaves for patches of yellow eggs, if found, crush the eggs. Chemical sprays can be used, but to prevent their need cover your plants with a fine netting such as enviromesh or voile net curtain.
Small White caterpillar on broccoli