Department of Biological Sciences

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    Dysdercusspp. as pests ofUrena Iobatain Sierra Leone
    (Taylor & Francis, 1983-03-01) Harris, Phil J.C.
    The status of Dysdercus superstitiosus (F.) and D. voelkeri Schmidt as pests of the jute‐substitute crop Urena Iobata L. in Sierra Leone is discussed. A significant correlation between the proportion of seeds with evidence of Dysdercus feeding and the proportion with non‐viable or abnormal embryos revealed these insects to be serious pests of U. Iobata seed crops. Damage is confined to the seeds and resulted in up to 70% non‐viability of seeds in some samples. The fibre yield is unaffected. Typical damage symptoms are described. Dysdercus adults migrated to U. Iobata cv. Ex‐Mokwa soon after the onset of flowering and remained throughout the period of seed production. High population densities were reached, and migration to later flowering varieties may have occurred. A wide range of alternative food sources enables Dysdercus populations to survive between successive U. Iobata crops. It is suggested that chemical control may be necessary for successful seed production.