CAUSAL AGENTS OF CROP DISEASES

Back to: Agricultural Science Primary 5

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There are many diseases that affect crop plants. The diseases are caused mainly by

1. fungi,
2. Bacteria,
3. Viruses and
4. Nematodes.

These are called causal agents.

 

Some common crop diseases are

1. Maize smut
2. Cassava mosaic
3. Tomato rot
4. Groundnut rosette

Maize smut, is a plant disease caused by the fungus Ustilago maydis, which attacks corn (maize) plants. The disease reduces corn yields and can cause economic losses.

  MAIZE SMUT

The cassava mosaic is a virus disease is an important cassava disease which causes low yields. It can be recognized on the cassava leaves which have spots ranging from light green to yellow.

AFFECTED BY CASSAVA MOSAIC

 

Tomato rot: A serious disorder of tomato, pepper, cucumber and eggplant, blossom end rot is an environmental problem (not fungal) most often caused by uneven watering. or by calcium deficiency.

Groundnut rosette:  groundnut rosette virus (GRV) is a peanut pathogenic virus found in Sub-Saharan Africa. It is transmitted between plants by insect vectors such as the groundnut aphids.

ROSETTED LEAVES

 

EVALUATION

1. Mention four disease causal agents
2. Mention four types of plant diseases.

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