Attraction and mortality of oriental fruit flies to SPLAT-MAT-methyl eugenol with spinosad

Abstract

Studies were conducted in 2007 and 2008 in Hawaii, USA to quantify attraction and feeding responses resulting in mortality of the male oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), to a novel male annihilation treatment (MAT) formulation consisting of specialized pheromone and lure application technology (SPLAT) in combination with methyl eugenol (ME) and spinosad (=SPLAT-MAT-ME with spinosad) in comparison with Min-U-Gel-ME with naled (Dibrom). Our approach involved a novel behavioral methodology for evaluation of slow-acting reduced-risk insecticides. Methyl eugenol treatments were weathered for 1, 2, 4, and 8 weeks in California, USA, and shipped to Hawaii for bioassays. In field tests involving bucket traps to attract and capture wild males, and in toxicity studies conducted in 1 m3 cages using released males of controlled ages, SPLAT-MAT-ME with spinosad performed similar to or outperformed the standard formulation of Min-U-Gel-ME with naled for material aged for up to 8 weeks in the 2008 tests. In laboratory feeding tests in which individual males were exposed for 5 min to the different ME treatments, mortality induced by SPLAT-MAT-ME with spinosad recorded at 24 h did not differ from that caused by Min-U-Gel ME with naled at 1, 2, and 4 weeks. Spinosad has low contact toxicity, and when mixed with SPLAT offers a reduced-risk alternative for control of B. dorsalis, without many of the negative effects to humans and non-targets of broad-spectrum contact poisons such as naled. Our results indicate that SPLAT-MAT-ME with spinosad offers potential for control of males in an area-wide integrated pest management (IPM) system without the need for conventional organophosphates. © 2009 The Netherlands Entomological Society.