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Detection of the Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), relies heavily on traps baited with trimedlure, a male-specific attractant. Originally used as a liquid, trimedlure is now dispensed from solid polymeric plugs (2 g active ingredient) that reduce volatilization and increase the effective longevity of the lure. Even so, plugs are attractive over a relatively short interval, and guidelines suggest that trimedlure plugs be replaced every 6 wk. The present study had 2 goals. First, at periodic intervals up to 10 or 12 wk, we evaluated the performance of plugs containing 4 g of trimedlure (i.e., twice the standard amount) to determine whether the increased loading resulted in an increased period of effective attractiveness. Second, we examined the relationship between trap captures and temporal changes in the residual amount and release rate of trimedlure. In 2 of the 3 field trials conducted in Hawaii and Florida, 4 g plugs weathered for as long as 8 wk, but not for 10 or 12 wk, performed as well as fresh liquid trimedlure applied to cotton wicks. In the other trial, plugs weathered for as long as 12 wk were as effective as fresh liquid. Chemical analyses revealed that the plugs were effective until the residual amount of trimedlure decreased below approximately 1.4 g and the release rate dropped below approximately 2.0 mg per h. The potential usefulness of 4 g trimedlure plugs in large-scale detection programs is discussed considering these findings. La detección de la mosca mediterránea de la fruta (moscamed), Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), depende en gran medida de trampas cebadas con trimedlure, un atrayente específico para machos. Utilizado originalmente como líquido, el trimedlure ahora se dispensa a partir de tapones poliméricos sólidos (2 g de ingrediente activo) que reducen la volatilización y aumentan la longevidad efectiva del señuelo. Aun así, los tapones son atractivos durante un intervalo relativamente corto, y las pautas sugieren que los tapones trimedlure se reemplacen cada 6 semanas. El presente estudio tuvo 2 objetivos. Primero, a intervalos periódicos de hasta 10 o 12 semanas, evaluamos el desempeño de los tapones que contenían 4 g de trimedlure (es decir, el doble de la cantidad estándar) para determinar si el aumento de la carga resultó en un mayor período de atractivo efectivo. En segundo lugar, examinamos la relación entre las capturas de trampas y los cambios temporales en la cantidad residual y la tasa de liberación de trimedlure. En 2 de los 3 ensayos de campo realizados en Hawái y Florida, los tapones de 4 g resistidos durante 8 semanas, pero no durante 10 o 12 semanas, funcionaron tan bien como trimedlure líquido fresco aplicado a mechas de algodón. En el otro ensayo, los tapones expuestos a la intemperie durante 12 semanas fueron tan efectivos como los líquidos frescos. Los análisis químicos revelaron que los tapones fueron efectivos hasta que la cantidad residual de trimedlure disminuyó por debajo de aproximadamente 1,4 g y con la tasa de liberación cayendo por debajo de aproximadamente 2,0 mg por hora. La utilidad potencial de los tapones de trimedlure de 4 g en los programas de detección a gran escala se discute considerando estos hallazgos.

The oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), is a global agricultural pest that attacks many commercially important fruits and vegetables. Many countries maintain trapping programs to detect incursions of this pest, and trapping relies heavily on methyl eugenol, a powerful attractant to B. dorsalis males, which typically is applied as a liquid to a cotton wick contained inside Jackson traps. However, this method is time-consuming, incurs high volatility (i.e., loss) of the lure, and entails health risks. Existing data indicate that solid dispensers of methyl eugenol are a viable alternative to the use of liquid lure. Based on fieldwork in a Hawaiian coffee field, the present study shows non-significant differences in captures of wild B. dorsalis males over 12-wk intervals between traps baited with a wick containing 6 mL of freshly applied liquid methyl eugenol and traps baited with a polymeric plug or wafer that contained a similar amount of methyl eugenol. The residual content of methyl eugenol also was measured for solid dispensers over the weathering period, but their long-lasting attractancy (≥ 12 wk) precluded identification of the threshold level of the lure below which solid dispensers were ineffective. Implications of these findings for trapping programs are discussed. La mosca oriental de la fruta, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), es una plaga agrícola mundial que ataca una gran variedad de frutas y verduras de importancia comercial. Muchos países mantienen programas de trampeo para detectar incursiones de esta plaga, y el trampeo depende en gran medida del metil eugenol, un poderoso atrayente para los machos de B. dorsalis, que generalmente se aplica como líquido a una mecha de algodón contenida dentro de las trampas Jackson. Sin embargo, este método requiere mucho tiempo, incurre en una alta volatilidad (pérdida) del señuelo y conlleva riesgos para la salud. Los datos existentes indican que los dispensadores sólidos de metil eugenol son una alternativa viable en vez del uso de señuelos líquidos. Basado en el trabajo de campo en cafetal de Hawái, el presente estudio muestra diferencias no significativas en las capturas de machos de B. dorsalis silvestres en intervalos de 12 semanas entre trampas cebadas con una mecha que contiene 6 ml de metil eugenol líquido recién aplicado y trampas cebadas con una tapón polimérico u oblea que contenía una cantidad similar de metil eugenol. El contenido residual de metil eugenol también se midió para dispensadores sólidos durante el período de exposición a la intemperie, pero su atractivo duradero (≥ 12 semanas) impidió la identificación del nivel umbral del señuelo por debajo del cual los dispensadores sólidos eran ineficaces. Se discuten las implicaciones de estos hallazgos para los programas de trampeo.

Detection of the Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), relies heavily on traps baited with trimedlure, a male-specific attractant. Originally used as a liquid, trimedlure is now dispensed from solid polymeric plugs (2 g active ingredient) that reduce volatilization and increase the effective longevity of the lure. Even so, plugs are attractive over a relatively short interval, and guidelines suggest that trimedlure plugs be replaced every 6 wk. The present study had 2 goals. First, at periodic intervals up to 10 or 12 wk, we evaluated the performance of plugs containing 4 g of trimedlure (i.e., twice the standard amount) to determine whether the increased loading resulted in an increased period of effective attractiveness. Second, we examined the relationship between trap captures and temporal changes in the residual amount and release rate of trimedlure. In 2 of the 3 field trials conducted in Hawaii and Florida, 4 g plugs weathered for as long as 8 wk, but not for 10 or 12 wk, performed as well as fresh liquid trimedlure applied to cotton wicks. In the other trial, plugs weathered for as long as 12 wk were as effective as fresh liquid. Chemical analyses revealed that the plugs were effective until the residual amount of trimedlure decreased below approximately 1.4 g and the release rate dropped below approximately 2.0 mg per h. The potential usefulness of 4 g trimedlure plugs in large-scale detection programs is discussed considering these findings.