Weathering Trials of Amulet Cue-Lure and Amulet Methyl Eugenol “Attract-and-Kill” Stations with Male Melon Flies and Oriental Fruit Flies (Diptera: Tephritidae) in Hawaii

Abstract

Amulet C-L (cue-lure) and Amulet ME (methyl eugenol) molded paper Þber "attract-and-kill" dispensers containing Þpronil were tested under Hawaiian weather conditions against Bactrocera cucurbitae (Coquillett) (melon ßy) and Bactrocera dorsalis (Hendel) (oriental fruit ßy), respectively. In paired tests (fresh versus weathered), C-L dispensers were effective for at least 77 d, whereas ME dispensers were effective for at least 21 d. Thus, C-L dispensers exceeded, whereas ME dispensers did not meet the label interval replacement recommendation of 60 d. Addition of 4 ml of ME to 56-d-old ME dispensers restored attraction and kill for an additional 21 d. This result suggested the Þpronil added at manufacture was still effective. By enclosing and weathering ME dispensers inside small plastic bucket traps, longevity of ME dispensers was extended up to 56 d. Fipronil ME and C-L dispensers also were compared, inside bucket traps, to other toxicants: spinosad, naled, DDVP, malathion, and permethrin. Against B. dorsalis, Þpronil ME dispensers compared favorably only up to 3 wk. Against B. cucurbitae, Þpronil C-L dispensers compared favorably for at least 15 wk. Our results suggest that Þpronil C-L dispensers can potentially be used in Hawaii; however, Þpronil ME dispensers need to be modiÞed or protected from the effects of weathering to extend longevity and meet label speciÞcations. Nonetheless, Amulet C-L and ME dispensers are novel prepackaged formulations containing C-L or ME and Þpronil that are more convenient and safer to handle than current liquid insecticide formulations used for areawide suppression of B. dorsalis and B. cucurbitae in Hawaii. KEY WORDS Þpronil, male annihilation, Bactrocera dorsalis, Bactrocera cucurbitae, suppression FIPRONIL IS A PHENYLPYRAZOLE insecticide that kills by contact or ingestion. It blocks the-aminobutyric acid (GABA)-regulated chloride channels of neurons in the central nervous system, causing overexcitation of the nervous system, and seizures (Cole et al. 1993). It is currently registered in 60 countries for a variety of insect pests attacking 50 crops, and in animal health, structural, and commercial turf pest control (Aventis 1996). Fipronil is marketed as Regent for control of lepidopterous and orthopterous pests on a broad range of Þeld and horticulture crops and coleopterous larvae in the soil; Combat and Over and Out for cockroaches and ants; Chipco Choice for Þeld corn, golf course, and commercial turf pest control; Termidor for termites; and Frontline and Top Spot for ßeas, ticks, and mites on domestic animals. It has been incorporated into cue-lure (Amulet C-L) and methyl eugenol (Amulet ME) molded paper stations and a protein bait (Amulet gel) for tephritid ßy control in the PaciÞc region. Bactrocera dorsalis (Hendel) (oriental fruit ßy) and Bactrocera cucurbitae (Coquillett) (melon ßy) are major fruit ßy pest species in Hawaii with 173 and 125 host plant species recorded, respectively (Metcalf and Metcalf 1992). Bactrocera is a tephritid ßy genus of at least 440 species distributed primarily in tropical Asia, the South PaciÞc, and Australia (White and Elson-Harris 1992). Methyl eugenol (ME) (4-allyl-1, 2-di-methoxybenzene-carboxylate) and cue-lure (C-L) [4-(p-acetoxyphenyl)-2-butanone] are highly attractive male lures to B. dorsalis and B. cucurbitae, respectively (Metcalf and Metcalf 1992). Cue-lure has not been isolated as a natural product, but it is rapidly hydrolyzed to form raspberry ketone (Metcalf and Metcalf 1992). At least 90% of the Dacinae species (comprised of the two major genera Bactrocera Macquart and Dacus F.) are strongly attracted to either ME or to C-L/raspberry ketone (Hardy 1979). For example, at least 176 species of the male Dacinae are attracted to C-L/raspberry ketone and 58 species to ME (Metcalf 1990). Of the 73 Bactrocera and Dacus species that are agricultural pests, 41 respond to C-L/ This article reports the results of research only. Mention of a proprietary product does not constitute an endorsement or a recommendation by the USDA for its use.