Weed and Pest summary

SUB-TOPIC- WEED

• Definition of Weed of Pest
• Types and Classification of pests
• Physical control, Chemical control and Biological control

WEED

Weed is any plant which is not cultivated and grows where it is not wanted. Such a plant is therefore a nuisance to the farmer. Examples are commelina, goat weed or the common water leaf (Talinumtriangulare) growing in a cassava field.

TYPES OF WEEDS

1. Annual weed: They grow and complete their life cycle in one year.
2. Perennial Weeds: They grow for more than one year.

PEST

A pest is any living organism, plant or animal, plant or animal, which can cause damage to cultivated crops, farm animals and humans.

CLASSIFICATION OF PESTS

Pest can be classified as

1. Insect Pest- Insect pests are animals without backbones and they belong to the group of animals called arthropods. Arthropod is a very large group of animals which, in addition to insects, includes crabs, shrimps, millipedes, spiders, centipedes and scorpions.
2. Non-insect pest- These are animals such as vertebrates like nematodes, mites, snails, slugse.t.c. and vertebrates like rats, squirrels, monkeys, glasscutters, birds, jackals that can cause damage to crop.

EVALUATION

1. What is a pest?
2. Mention two classes of pests.
3. What are weeds?
4. List five examples of weeds and state three features of weeds.

CLASSIFICATION OF INSECT PESTS

Insect can be classified based on their mouth parts which are different in different insect groups.

1. Biting and chewing Pests.
2. Piercing and sucking Pests.
3. Boring insects.

NATURE OF DAMAGE

1. Destruction of crop tissues
2. Stunted growth
3. Weakened crop plant
4. Pierced holes can be infested with harmful organism like fungi, bacteria and viruses
5. Transfer of harmful organism from infected crop to the healthy one.
6. It causes ill-health to man and livestock.

CONTROL MEASURES

• Physical Control
• Chemical Control
• Biological Control