Comparative Studies on the Biology and Morphology of Earias Insulana ‎‎(Boisd.) And Earias Vittella (Fab.) (Lepidoptera: Noctuidae) ‎Reared On Okra

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Mursal ‎, Elhadi Ibrahim
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The field survey and laboratory experiments were conducted during the course of this study ‎at the Demonstration Farm, Shambat area and at the Entomology laboratory of the Faculty ‎of Agriculture, University of Khartoum. The study aimed to investigate the Biology and the ‎Morphology of the spiny bollworm, Earias insulana (Boisd.), known as Egyptian bollworm ‎and the spotted bollworm, Earias vittella (Fab.) known also as the shoot and fruit-borer of ‎okra, reared on okra plant.‎ The development of the immature stages of the spiny bollworm and the spotted bollworm ‎was followed under laboratory conditions, with average range of temperature (28-20°C) and ‎R.H. (63-44%). Egg hatching of Egyptian bollworm and the spotted bollworm took 4 days. ‎Larval duration of Earias insulana (Boisd.) lasted for 10 to 13 days with an average of 11.20 ‎‎± 1.22 days. Pupal period ranged from 10 to 12 days with an average of 10.90 ± .56 days. ‎the life cycle lasted for 25 to 27 days averaging 26.10 ± .87 days. while for Earias vittella ‎‎(Fab.) larval duration lasted 11 to 12 days with mean of 11.80 ± 0.42 days. pupal period ‎ranged from 7 to 9 days with an average of 7.80 ± 0.78 days. the life cycle lasted for 23 to ‎‎25 days averaging 23.0 ± 0.84 days.‎ The morphological results showed that the eggs is small globular in shape with parallel ‎longitudinal ridges projecting upwards. The colour of larva of Earias insulana (Boisd.) ‎ranged from light grey to grey and spiny terminal each tubercles. While the colour of larva ‎of Earias vittella (Fab.) was brown having a dorsal milky streak. Both species have the same ‎pupal obtect shape, and the colour was either white or light brown. The adult of spiny ‎bollworm is green in colour, while in the spotted bollworm, the forewings are long and ‎narrow, cream with green longitudinal median wedge. ‎ The distinction between the male and female, is that the male is smaller than the female in ‎the size and the latter has V shape at the end of the anal part but the male has thick hairs ‎at the end of anal part.‎
November 2005