(a) State each of the disease condition observed on specimens J (MAIZE PLANT) and K (CASSAVA LEAF) and their causative agents.
(b) Explain the mode of transmission of the diseases on each of specimens J and K.
(c) State two effects each of the diseases on Specimens J and K and two control measures of each
(d) Name two other diseases of specimen K.
Explanation
(a) Specimen J is maize plant with leaves showing a mosaic pattern/infection, tomato plant, showing leaf curl.
- The causative agent for this Condition is virus.
Specimen K is cassava leaf, showing leaf spot.
- The causative agent is fungus.
(b) Mode of transmission:
- For specimen J, the virus is transmitted by an aphid vector.
- For specimen K, the fungus is air- borne, water and rain splash
(c) Effects of each of the abnormalities on crops are:
Specimen J (effects):
- It results in stunted growth of plants.
- It leads to reduction in yield of plants.
- It causes reduction in the photosynthetic area of the leaf.
Control measures include:
- early planting:
- removal and burning of infected plants;
- eradication of insect vectors;
- use of resistant varieties; and
- crop rotation
For specimen K (effects);
- It causes reduction in yield of crop or plant.
- It leads to the reduction in the rate of growth of plants.
- It also leads to reduction in the photosynthetic area of the leaves.
Control measures include:
- application of fungicides,
- use of resistant varieties,
- removal and burning of infected plants, and
- crop rotation.
(d) Other diseases of specimen K are;
- Cassava mosaic
- Cassava blight