author(s)
Jacobs M Adesina, Thomas I Ofuya and Yallappa Rajashekar

abstract
The objective of the present study was to investigate the insecticidal efficacy of Bridelia micrantha, Chasmanthera dependens and Vernonia cinerea under ambient laboratory conditions in the management of Dysdercus superstitious (Herrich Schaffer) (Hemiptera: Pyrrhocoridae). The incidence of each aqueous extracts on D. superstitious for repellency and mortality was monitored at 24 h interval for 4 days, while nymph emergence was monitored and recorded. The result indicated that D. superstitious repellency, mortality and nymph emergence were concentration (dosage) and exposure time dependent. Across treatment, dishes treated with 2.0 ml extract significantly (P<0.05) influenced the bioactivity of the insects on treated surface compared to untreated surface. Adult insects exposed to 2.0 ml extracts for 24 and 48 h exposure time significantly (P<0.05) exerted greater adult repellency (90%), mortality (90%) and suppressed nymph emergence (0%). Among the three tested plants B. micrantha showed the best effective values followed by C. dependens and V. cinerea respectively in significantly repelling the insect from treated surface, caused adult mortality and inhibited nymphs emergence. Hence use of B. micrantha to suppress cotton stainers infestation on okra or cotton plants is herewith discussed.