Biology of scrobipalpa blapsigona meyrick (lepidoptera: gelechiidae), a “bud worm” pest of eggplant
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Date
2002-11-29
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Abstract
Studies were conducted in the field to determine the most susceptible of four cultivars (Black Beauty, Obolobo, Amantin and Aworoworo) of eggplant to attack by Scrobipalpa blapsigona Meyrick (Lepidoptera: Gelechiidae). The most susceptible cultivar, Aworoworo, was used to study the population dynamics of the moth in relation to temperature and rainfall.
Other parameters studied were life cycle, fecundity and longevity of the moth. Chaetotaxy of the larvae of S. blapsigona was also investigated and setal maps drawn to help in the identification of the insect.
There was negative correlation between temperature and population level of S. blapsigona but this was not significant. There was however, significant negative correlation between rainfall and population level. The population increased during dry or low rainfall periods while the reverse occurred during high rainfall regimes.
Total developmental period was about 30 days. Five larval instar stages occurred during the development of S. blapsigona. Growth ratio of head capsule widths decreased at subsequent moults indicating a departure from Dyar’s law.
Oviposition period was 13 days during which period the female laid 128 eggs. Longevity of the moths was influenced by sex and mating. Generally the female moth lived longer than the male. Mated female and male moths lived significantly shorter than the unmated.
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A thesis submitted the School of Postgraduate Studies, Kwame Nkrumah University of Science and Technology, Kumasi in partial fulfilment of the requirements of Master of Science, 2002