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Title: TRAPPING COMPARISONS OF STANDARD GRANDLURE WITH THE SUPER FORMULATION FOR BOLL WEEVILS IN THE RIO GRANDE VALLEY OF TEXAS

Author
item Armstrong, John
item Spurgeon, Dale
item Suh, Charles

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/5/2005
Publication Date: 6/28/2005
Citation: Armstrong, J.S., Spurgeon, D.W., Suh, C.P. 2005. Trapping comparisons of standard grandlure with the super formulation for boll weevils in the Rio Grande Valley of Texas. In: Proceedings of the Beltwide Cotton Conferences, January 4-7, 2005, New Orleans, Louisiana. 2005 CDROM.

Interpretive Summary: Where the boll weevil has been eradicated, monitoring programs remain necessary to guard against re-introduction of this important cotton pest. These programs, called maintenance programs, detect weevils through weekly inspections of traps baited with lures containing synthetic pheromone (a mixture of specialized chemicals male boll weevils release to attract other weevils). Recent studies suggest maintenance program cost could be reduced if a modified lure (the superlure), featuring increased amounts of pheromone and the addition of a plant odor, would allow the traps to be inspected less often without reducing their effectiveness. We compared the effectiveness of the superlure to that of the standard lure, each replaced on two different schedules (lures remaining in the traps for either two or four weeks), during three separate month-long trapping periods. Important differences between the lures in the average numbers of weevils captured each week were found only in the fourth week of the first trapping period. During that week, the superlure that had been replaced at two weeks caught the most weevils (45 weevils/trap), followed by the superlure that was not replaced (29 weevils/trap) and the standard lure replaced after two weeks (28 weevils/trap). The standard lure that was not replaced caught the fewest weevils (12 weevils/trap). Numbers of weevils captured at other times may have been too low for reliable comparisons, but they tended to follow the same pattern as for the first trapping period. These findings, although preliminary, suggest the superlure left in the trap for up to a month may be as attractive to boll weevils as the standard lure replaced every two weeks.

Technical Abstract: The Southeastern Boll Weevil Eradication Program has recently emphasized the importance of reducing maintenance program costs within eradication zones. One suggested cost-reduction measure is the use of an extended-life "superlure" in the pheromone traps. However, no field study has adequately evaluated superlure effectiveness relative to a standard lure. We compared captures of boll weevils (Anthonomus grandis Boheman) in traps baited with a standard lure (10 mg grandlure) to those of traps baited with the superlure (30 mg eugenol plus 25 mg grandlure) in a study near San Benito, TX. Four treatments (standard and superlure, replaced bi-weekly or not replaced) were included in three month-long experiments conducted during distinct seasonal periods (February-March, June-July, and October-November) of 2004. Meaningful differences among the lure treatments were observed only in the final week of the first trapping period, when weevil captures (mean ± SE) were highest for the superlure replaced after 2 wks (45.0 ± 4.33 weevils/trap), intermediate for the superlure not replaced (29.0 ± 4.19) and the standard lure replaced after 2 wks (27.7 ± 4.08), and lowest for the standard lure not replaced (11.7 ± 4.48 weevils/trap). Captures during other trapping periods may have been too low to detect differences among lure treatments, but numerical trends were similar to those observed during the first period. Our preliminary results do not suggest trapping effectiveness of the superlure replaced monthly would be different from that of the standard lure replaced bi-weekly.