Pieris brassicae

Pieris brassicae (Cabbage pest)

Kishor Dahal

Systematic position

Kingdom: AnimaliaPhylum: ArthropodaClass: InsectaOrder: LepidopteraFamily: PieridaeGenus: PierisSpecies: brassicae

Introduction

Pieris brassicae is commonly called cabbage butterflyor large white butterfly. In the context of Nepal it isfound as subspecies Pieris brassicae nepalensis.

Morphology

The cabbage butterfly is yellowish white in color. Theapical angle of forewings black while rest of the wingis yellowish white. There are two Black spots on eachforewings. The length of the butterfly is 65mm acrossthe wing expansion. Females are little longer thanmale.

Distribution

It is cosmopolitan in distribution where cabbage is cultivated.

The main host plant is cabbage but it also feeds oncauliflower, radish, broccoli etc.

Host plant

The larva of Pieris damage the leaves of cabbage. Theyfeed on the leaves of cabbage and cauliflower and thusdestroy them.

Importance

Life cycle

The young larva are about 2 mm in length and light yellow in color. The body is hairy.

The female lays 50-80 eggs usually in cluster on the undersurface of the leaves. The eggs are yellow in color, flask shaped and about 1 mm long and 0.5 mm wide. Incubation period varies between 3 days in summer and 18 days in winter.

The larval period last for 15 days in summer to 40 days in winter. Full grown larva is 19 mm in length, bluish green in color with yellowish grey shades and posses 5 pairs of pseudo legs

It pupates on leaves of cabbage. The pupa is enclosed within a silken cocoon. The pupal period varies from 7 days in summer to 29 days in winters. The female copulates just after emergence and begins to lay eggs.

Life cycle

Life cycle

Initially the caterpillars feed in groups and at this stagethey should be collected and destroyed. The full growncaterpillars are not much active and can be seenmoving anywhere in the fields, therefore, they can bepicked by hand and killed. If necessary, spraying of0.05 % carbaryl or 0.03 % dichlorovos or 5 %malathion is quite satisfactory in checking theirinfestation.

Control measures