Page 46 - Agriculture_Form_3

Agriculture for Secondary Schools

(b) Describe how the identified weeds can be effectively managed in the
field.
2. Demarcate the sorghum field into five sub-plots (A-E), then apply different
weed management practices as follows:
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(a) Sub-plot A, remove weeds using a hand hoe;

(b) Sub-plot B, remove weeds by hand-pulling;
(c) Sub-plot C, grow a cover crop to help control weeds;

(d) Sub-plot D, use herbicide to kill weeds; and

(e) Sub-plot E, combine two or more of the above methods.

3. Observe and compare the weed control methods used in sub-plots A-E, and
comment on which method(s) are:
(a) easier to apply;

(b) more effective in controlling weeds.

Management of pests and diseases in sorghum

Sorghum is affected by many pests and diseases that can reduce its growth,
weaken plants, lower yields and reduce grain quality. Some pests attack the
flowers, stems, leaves or grains, while others suck plant sap, causing serious
damage. Most of the diseases that affect sorghum are caused by fungi, bacteria
or viruses. Recognising the symptoms of pests and diseases attacking the crop is
important for early control. Although there are many pests and diseases attacking
sorghum, this section focuses on the most common ones. It highlights their effects
on sorghum, how to identify and manage them effectively.

Common sorghum pests and their management
Birds: These are major pests of sorghum, especially during the grain maturing
stages. Birds, such as Quelea, feed on sorghum grains, causing heavy losses in
the field. Their presence is identified by the presence of flocks of birds in sorghum
fields and partially eaten grains. They can be controlled by scaring them away
using noise-making devices like tins and scarecrows, harvesting early before
birds cause severe damage, and planting bird-resistant sorghum varieties with
hard seed coats. Figure 3.2 (a) shows Quelea birds in a sorghum field.

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