Thursday, October 23, 2008

Beauty or Beast?

This picture captured on the 20th September, shows the lovely black tips to the wings of the Large White butterfly Pieris brassicae.

It is very difficult sometimes to tell the difference between the Large White and Small White butterflies as there can be an overlap in sizes. However, the black markings at the apex of the forewings are always more extensive in the Large White and generally follow a boomerang shape.

This butterfly is hated by most gardeners due to the destructive nature of their caterpillars on cabbages and other brassica plants. So to compensate for the annual mass genocide of this species, my wife Bron plants a few cabbages in pots and also a few nasturtiums around the garden to help them on the way.

Covering the target plants with horticultural fleece or fine netting should prevent the butterflies laying their eggs in the first place. Netting should be held away from the leaves and not draped over them otherwise the butterfly may reach them. This has the additional benefit of protecting from Pigeons which will also feed on brassicas. If no netting is available, then inspect the leaves of the host plants in July when adults are seen, for eggs and small caterpillars - crush by rubbing with a finger. They are usually around the outer edges where the female probably has a better grip while she places them in clumps. The eggs are very obvious as shown in the photograph below.