SS 2 BIOLOGY
TOPIC: LIFE CYCLE/HISTORY OF SOME CROP PESTS
LIFE CYCLE/ HISTORY OF GRASSHOPER
Grasshopper undergoes incomplete metamorphosis. The Life cycle involves the eggs, nymphs and adults. The Life History.
The female after mating with the
male ,digs a hole in the soil with it’s ovipositor near the roots of plant and lays about 40 to 100 eggs in the hole. It produces a protective material to cover the eggs. After about 3days, the eggs hatch into nymphs. The nymphs moult several times and hop about feeding on the shoots of plants nearby. They begin to migrate into areas where there are cassava farms and start feeding on cassava leaves untill adult stage is attained.
BEAN WEEVIL
THE LIFE CYCLE
It undergoes complete metamorphosis, it involves the eggs, larvae, pupae, and adults.
LIFE HISTORY: The adult male mates with the female and the female lays fertilized eggs into bean pod in the farm. The eggs hatch into larvae, which enter into the bean seeds before harvesting. In the store, the larvae feed on the cotyledons of the beans. The larvae develop into pupae in the store and the pupae later develop into adults , which fly away to mate again in the farm.