Page 68 - Agriculture_Form_3

Agriculture for Secondary Schools

management includes using disease-free seeds, planting resistant rice varieties,
and avoiding excessive nitrogen fertilisation, which can make plants more
susceptible to infection. Proper field sanitation and crop rotation also help reduce
disease incidence. Figure 4.11 shows Bacterial leaf blight disease in paddy plants.
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Figure 4.11: Bacterial leaf blight disease in paddy plants

Sheath blight disease: Sheath blight is a fungal disease that affects rice, causing
oval, water-soaked lesions on leaf sheaths. These lesions expand and merge,
weakening the plant and leading to lodging, which reduces yield. The disease
thrives in warm, humid conditions and is more severe in densely planted fields
with poor air circulation. Effective management includes improving field drainage
to reduce moisture levels, planting resistant varieties, and applying fungicides
when necessary. Proper plant spacing and crop rotation also help minimise the
spread of the disease. Figure 4.12 shows paddy plants affected by sheath blight
disease.

Figure 4.12: Sheath blight in paddy plants

Student’s Book Form Three 59

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AGRICULTURE F3.indd 59