Pieris brassicae

Introduction, life cycle, damage pattern and control measures of Pieris brassicae

1. Pieris brassicae (Cabbage pest) Kishor Dahal

2. Systematic position Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Lepidoptera Family: Pieridae Genus: Pieris Species: brassicae

3. Introduction Pieris brassicae is common ly called cabbage butterfly or large white butterfly. In the context of Nepal it is found as subspecies Pieris brassicae nepalensis .

4. Morphology The cabbage butterfly is yellowish white in color. The apical angle of forewings black while rest of the wing is yellowish white. There are two Black spots on each forewings. The length of the butterfly is 65mm across the wing expansion. Females are little longer than male.

5. Distribution It is cosmopolitan in distribution where cabbage is cultivated.

6. The main host plant is cabbage but it also feeds on cauliflower, radish, broccoli etc. Host plant

7. The larva of Pieris damage the leaves of cabbage. They feed on the leaves of cabbage and cauliflower and thus destroy them. Importance

8. 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.

9. 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.

10. Life cycle

11. Life cycle

12. Initially the caterpillars feed in groups and at this stage they should be collected and destroyed. The full grown caterpillars are not much active and can be seen moving anywhere in the fields, therefore, they can be picked by hand and killed. If necessary, spraying of 0.05 % carbaryl or 0.03 % dichlorovos or 5 % malathion is quite satisfactory in checking their infestation. Control measures