Gce Model Questions Vol1 2025 Agricultural Science Question 8

Practice essay / theory question 8 from the 2025 Gce Model Questions Vol1 Agricultural Science examination. This question covers Plant Diseases .

Gce Model Questions Vol1 2025 Agricultural Science Essay / Theory

Topic: Plant Diseases

Question 8 GCE_MODEL_QUESTIONS_VOL1 • 2025 • AGRICULTURAL_SCIENCE • essay

An orchard of 5 ha of orange trees in southwestern Nigeria has recently shown sudden wilting, yellowing of leaves and premature fruit drop on several trees. Laboratory analysis of leaf samples isolated a fungus that produces conidia 5–7 µm long. The disease is known to be spread by wind‑borne spores and by contaminated pruning tools.

Question Parts

( a )

Name the disease most likely responsible for the observed symptoms and explain how each component of the disease triangle (host, pathogen, environment) contributes to its development in this orchard.

( b )

Assuming each infected tree can, on average, infect 1.5 new trees per week (through wind‑borne spores and contaminated tools), and that the orchard initially has 4 infected trees, determine after how many whole weeks at least 90 % of the orchard will be infected. The orchard density is 100 trees per hectare.

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About This Question

This is Gce Model Questions Vol1 2025 Agricultural Science Question 8. It is one of the essay questions from the 2025 Gce Model Questions Vol1 Agricultural Science examination.

The question covers Plant Diseases .

View More Gce Model Questions Vol1 2025 Agricultural Science Questions More Gce Model Questions Vol1 Practice Questions Back to Questions

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