Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/20/2012
Publication Date: 9/26/2012
Citation: Lopez, J., Latheef, M.A., Fritz, B.K. 2012. Effect of spinosad and sucrose mixtures on gustatory response and mortality of adult boll weevils (Coleoptera: Curculionidae) by feeding and field assessment. Journal of Cotton Science. 16(3):152-159.
Interpretive Summary: Active boll weevil eradication zones are threatened by the development of boll weevil populations on un-reported cotton plants and native host plants during and between cotton growing seasons. Further, complete eradication in these areas is needed to prevent weevils from dispersing into post-eradication zones. A novel pest management approach using a combination of an attractant, feeding stimulant, and insecticide was evaluated in the laboratory and field. Results showed great potential for use of the pest management technology as a barrier application between active and post-eradication zones with reduced environmental impacts. With further development of a sprayable formulation, the pest management technology could complement current insecticide application strategies that are critical to the continued success of boll weevil eradication programs.
Technical Abstract: Successful completion and long-term maintenance of eradication of boll weevil (BW), Anthonomus grandis grandis Boheman, in Texas depends upon the development of control technologies to complete elimination of BW reproduction in active eradication zones and prevent dispersal into and reproduction in post-eradication zones. Adult control technology through the use of pheromone as an attractant and a feeding stimulant mixed with a toxicant may be a viable suppression technique. A commercial formulation of spinosad was mixed with 10% sucrose and evaluated as an ingested toxicant to field-captured adult BW with additional field assessments of spinosad/feeding stimulant mixtures or bait formulations with grandlure as an attractant. When spinosad was mixed with 10% sucrose solution and ingested, it was highly toxic to BW adults with a lethal concentration to kill 90% (LC90) of 27.79 ppm (a.i. wt:vol) after 24 hours. Gustatory (ingestion) response of BW to toxic concentrations ranging from 28 to 10,000 ppm (a.i. wt:vol) of spinosad mixed with 10% sucrose was somewhat inhibitory compared to the sucrose solution alone but no consistent patterns were present. In field tests, several bait formulations mixed with spinosad at 300 ppm (a.i. wt:vol) and sprayed on individual yaupon shrubs baited with a pheromone lure killed BW in numbers similar to BW captured in individual traps baited with the pheromone lure alone. This study suggests that sugar-based adult control technologies with spinosad as a toxicant and grandlure as an attractant may provide a potential strategy to attract and kill boll weevils in environmentally-sensitive non-cotton habitats.