Bioecology And Economic Injury Levels (Eil) Of Dysdercus Volkeri F (Heteroptera: Pyrrhocoridae) On Sunflower (Helianthus Annuus L.) In Samaru Zaria, Nigeria

📄 Project Abstract

Field and laboratory studies were conducted on the bioecology and economic injury levels (EIL) of Dysdercus volkeri Fab. (Pyrrhocoridae: Heteroptera) on sunflower in Samaru Nigeria. The objectives of the studies were to determine the biology of D. volkeri, susceptible stage of sunflower for damage by D. volkeri, the economic injury levels of D. volkeri, the influence of weather factors on D. volkeri and to screen different accessions of sunflower for resistance to D. volkeri damage. The result of the studies indicated that growth stages R7 (when the back of the head has started to turn a pale yellow colour), R8 (when the back of the head is yellow but the bracts remain green) and R9 (when the bracts become yellow and brown and the stage is regarded as physiological maturity) took about 10, 14, 14 days respectively. The result of the biological studies showed a marked difference between the life cycle of D. volkeri in the field and that in the laboratory. Eggs laid by adult in the labor...