Page 81 - Agriculture_Form_3

Agriculture for Secondary Schools

2. Select small plots of the common bean field on the school farm. Apply
weed control methods that are effective. You may also combine two or more
methods in one plot. Observe what happens in each plot and compare the
results.
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3. Record all your work activities and lessons learnt in your portfolio.

Exercise 5.5

1. A weedy bean plot produces fewer pods than a clean one. Explain why this
happens.

2. Suggest a plan to control weeds using different methods.
3. Explain the advantages and disadvantages of manual weeding compared to
chemical weed control.

4. Summarise different methods of weed control in common bean fields. Explain
how they work and when to use.

Pest and disease management in the common bean field

Common beans are attacked by various pests and diseases that ultimately reduce
plant growth, health, and yield. Pests may attack leaves, stems, roots, pods or
seeds. Diseases may show signs or symptoms on leaves, stems, flowers, pods and
other parts of the plants. Some of the symptoms are leaf spots, wilting, or root
rot. Early detection and good control methods help to reduce crop loss. Proper
management leads to a better and healthier bean crop.

Common pests in common beans and their management
Common bean plants are often attacked by insect pests. Knowing each pest and
how to manage it is important. Management of insect pests helps to protect bean
crops and hence increase production. Some of the common pests are presented in
the following sub-sections.
Bean fly: This is an insect pest that harms young bean plants (Figure 5.3 (a)).
Its larvae feed on the roots and lower stems. Feeding on roots and lower stems
causes the affected plant to wither and later die. Early sowing helps to avoid
heavy attacks from the bean fly. Mulching discourages pests from laying eggs.
Use of resistant bean varieties can also reduce the damage.

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