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Agriculture for Secondary Schools

Common pea diseases and their management
Like other legumes, common peas are affected by several diseases caused by
fungi or viruses. These diseases attack leaves, stems, roots, or pods, especially
in wet or poorly drained fields. Early identification and good management help
reduce damage and improve yields. The most common diseases in Tanzania are
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described here.
Powdery mildew: This is a fungal disease. It causes white, powdery spots on the
leaves and stems of pea plants (Figure 6.5 (a)). The disease slows down growth
and lowers pod production. Powdery mildew can be managed through the use
of resistant pea varieties, field sanitation, optimal spacing and sulphur-based
fungicides. The disease can be spread through overhead irrigation, hence it is
important to avoid wetting of leaves during irrigation. Where necessary, sulphur-
based fungicides must be applied with the advice of an agricultural extension
worker.

Figure 6.5 (a): Powdery mildew symptoms on common pea leaves and stem

Downy mildew: This disease causes yellow patches on the upper side of leaves
and grey or white fuzzy growth underneath (Figure 6.5 (b)). The disease spreads
easily in wet, crowded, or shaded conditions. It weakens the plant and reduces
yield. Management of downy mildew requires the use of proper plant spacing to
allow air movement. Growing the crop in areas that are too wet or shaded must be
avoided. Infected leaves should be removed and destroyed to reduce the spread
of the disease. When required, recommended fungicides may be used under the
guidance of an agricultural extension worker.

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