Rice tungro disease is a serious viral disease in rice-growing regions. (i) Name the causative single or viruses involved. (ii) Describe symptoms of rice tungro infection in young rice plants. (iii) Give three control strategies applicable to manage rice tungro.

Boresha ili kuona majibu ya mfano.

For each of the following pests, do the following: False codling moth, aphids, and maize stem borer. For each pest: (i) name a host crop; (ii) describe the type of damage; (iii) suggest two control measures.

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(c) Discuss three methods used in breeding cross-pollinated crops, giving advantages and disadvantages of each method.

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(c) Explain epiphytotic disease: (i) Define the term. (ii) Describe four environmental and biological factors that can lead to epiphytotics.

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(c) Define each of these: (i) Quarantine (ii) Resistant variety (d) Give four advantages and three limitations of using resistant crop varieties to control plant diseases.

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