(a) Outline the life cycle of the bean beetle [6 marks] (b)(i) Describe briefly four damages done by cotton stainer to cotton plants on the field. [6 marks] (ii) Name four alternate hosts of cotton stainer [4 marks]
Explanation
(a) (i) An adult beetle has a short life span of about 6-8 days after emergence. (ii) After this emergence, mating takes place. (iii) The female begins to lay eggs before she dies. (iv) The eggs are attached to the surface of the seed and the larvae bore directly into the seed where they feed and pupate. (v) Adult beetles emerge through circular Either roles from about 22 to 28 days after the eggs have been laid. (vi) 3-4 beetles may emerge from a single seed.
(b)(i) Cotton stainer may damage embryos of young cotton Or bolls. This can cause cotton bolls to abort. It may introduce pathogenic organisms e.g. fungus while feeding on matured bolls.The lint may be stained by pathogenic organisms introduced and this may reduce oil content of the cotton seeds and viability of cotton seeds may be reduced. It can reduce market value or quality of cotton lint.
(ii) Alternate hosts of cotton stainer are: Kenaf, millet, Okra, maize, baobab, guinea corn, Silk cotton tree etc.