Bionomics of Smicronyx guineanus Voss and Sm. umbrinus Hustache (Coleoptera:Curculionidae) : potential biocontrol agents of Striga hermonthica (Del.) Benth. (Scrophulariaceae) in Burkina Faso (West Africa)

• Main Author: Traoré, Doulaye
• Other Authors: Stewart, R. K. (advisor)
• Format: Others
• Language: en
• Published: McGill University 1995
• Subjects: Smicronyx > Burkina Faso.; Purple witchweed > Biological control > Burkina Faso.
• Online Access: http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=28936

A three-year (1991-1993) investigation was done in the field and laboratory to study the bionomics of Smicronyx guineanus Voss and Sm. umbrinus Hustache and the spatial distribution of Striga hermonthica (Del.) Benth. Studies on the life history of the weevils were undertaken. Seasonal activity and habits were established by monitoring life stages in the field. A behavioral Time Budget of Smicronyx adults was established in semi-field conditions. Dispersion patterns and the optimum sample size for Smicronyx and Striga were determined. Smicronyx adults as well as Striga plants were aggregated in the field. Smicronyx larvae were located in the upper stratum of the witchweed (93.2%) where they make galls and destroy large number of seeds. The effect of precipitation on emergence of Smicronyx adults was investigated in the insectary. The optimum rainfall required for Smicronyx adult emergence ranged from 30 to 40 mm. Good synchrony and positive association of Sm. guineanus and Sm. umbrinus with S. hermonthica were observed. There are good prospects for augmentation and/or conservation of Smicronyx populations as part of an integrated control strategy of S. hermonthica.