Development and Biological Activity of a New Antagonist of the Pheromone of the Codling Moth Cydia pomonella

Abstract

A new pheromone antagonist of the codling moth Cydia pomonella is reported. Presaturation of the antennae of the insects with vapors of the antagonist (E,E)-8,10-dodecadienyl trifluoromethyl ketone, analogue of the main component of the pheromone (codlemone), resulted in lower electrophysiological responses to the pheromone relative to untreated insects. In the wind tunnel, the compound elicited a remarkable disruptive effect on all types of behavior of males flying toward a source baited with a pheromone/antagonist blend in 1:1, 1:5, and 1:10 ratios. The insects displayed erratic flights in the presence of the antagonist, as shown by their flight parameters in comparison to insects attracted to the pheromone alone. In the field, traps baited with mixtures of 1:10 codlemone/antagonist attracted considerably lower numbers of males than the natural attractant. The antagonist, however, did not inhibit the pheromone-degrading enzymes present in male antennae, suggesting that trifluoromethyl ketones are not sufficiently electrophilic to produce a stable intermediate adduct with a cysteine residue of the enzyme, a mechanism previously proposed for oxidase inhibition in insects. Overall and taking into account our previous reports and, particularly, the reduction in damage induced in maize fields by a trifluoromethyl ketone analogue of the pheromone of Sesamia nonagrioides (Sole, J.; Sans, A.; Riba, M.; Rosa, E.; Bosch, M. P.; Barrot, M.; Palencia, J.; Castella, J.; Guerrero, A. Reduction of damage by the Mediterranean corn borer, Sesamia nonagrioides , and the European corn borer, Ostrinia nubilalis , in maize fields by a trifluoromethyl ketone pheromone analog . Entomol. Exp. Appl. 2008, 126, 28-39), the antagonist might be a new candidate to consider in future strategies to control the codling moth.

Inhibition of the Responses to Sex Pheromone of the Fall Armyworm,Spodoptera frugiperda

“…Dissimilar results were obtained in 1:1 and 0.1:1 inhibitor:pheromone mixtures, because whereas the former formulation displayed an antagonist effect, the latter was apparently synergist, but in neither case were the results significant. Overall, these results agree with those previously reported on S. nonagrioides (Riba et al 2001), O. nubilalis (Riba et al 2005; Solé et al 2008a), Cydia pomonella (Giner et al 2009), and Zeuzera pyrina (Muñoz et al 2011), emphasizing the potential utilization of these compounds in pest control. Moreover, the low toxicity displayed by TFMKs has been noticed on Swiss mice (Ashour and Hammock 1987; Riba et al 2001) and in aquatic toxicity studies on algae growth and survival (Rosa et al 2006).…”

Plant volatiles challenge inhibition by structural analogs of the sex pheromone in Lobesia botrana (Lepidoptera: Tortricidae)

“…The following experiments were run in succession as the information obtained from the fi rst was needed to perform the foldecrease in the number of males caught in traps baited with mixtures of the pheromone and the antagonist compared with the pheromone alone (Riba et al, 2001(Riba et al, , 2005Giner et al, 2009). In this regard, there is a remarkable reduction in damage induced by S. nonagrioides and O. nubilalis in maize fi elds treated with an analog of the major component of S. nonagrioides pheromone (Solé et al, 2008a).…”

“…Thus, TFMK analogs of the pheromones of S. nonagrioides and C. pomonella inhibit pheromone response at 1:1 pheromone : analog ratio (Bau et al, 1999;Giner et al, 2009), whereas for O. nubilalis the corresponding analog was active at the minimum ratio of 1:5 (Riba et al, 2005;Solé et al, 2008b). In the processionary moth T. pityocampa, a structural TFMK analog, in which the acetate group of the pheromone was replaced by the CH 2 COCF 3 group, a 5% blend with the pheromone decreased the close approach and source contact behaviour (Quero et al, 1995).…”

“…Among the structural analogs, methyl ketones (MKs) and, particularly, trifl uoromethyl ketones (TFMKs), in which the acetate group has been replaced by CH 3 CO or CF 3 CO, respectively, are good disruptants of pheromone perception in a number of lepidopteran species, such as Spodo ptera littoralis Boisduval (Duran et al, 1993;Rosell et al, 1996), Plutella xylostella (L.) (Prestwich & Streinz, 1988), Thaumetopoea pityocampa Denis & Schiffermüller (Parrilla & Guerrero, 1994), Sesamia nonagrioides (Lefevbre) (Bau et al, 1999;Riba et al, 2001), Mamestra brassicae (L.) (Renou et al, 1997), Ostrinia nubilalis (Hübner) (Riba et al, 2005), Bombyx mori (L.) (Pophof et al, 2000), Antheraea polyphemus (Cramer) (Vogt et al, 1985), Cydia pomonella (L.) (Giner et al, 2009), Zeuzera pyrina (L.) (Muñoz et al, 2011), Spodoptera frugiperda Smith (Malo et al, 2013) and Tuta absoluta (Meyrick) (Dominguez et al, 2016). In the fi eld, these chemicals induce a signifi cant Plant volatiles challenge inhibition by structural analogs of the sex pheromone in Lobesia botrana (Lepidoptera: Tortricidae) INTRODUCTION Pheromones are an important element in integrated pest management (IPM) programs, where many insect pests are successfully monitored and controlled by mass trapping and/or mating disruption (Witzgall et al, 2010).…”

Formate Analogs as Antagonists of the Sex Pheromone of the Honeydew Moth, Cryptoblabes gnidiella: Electrophysiological, Behavioral and Field Evidence

“…However, it is possible that blocking of the pheromone receptor responses by the analogs could occur with exposure to increased amounts of the formates or a shorter latency between exposure to the formates and the pheromone. A recent study (Giner et al, 2009), using (E,E)-8,10-dodecadienyl trifluoromethyl ketone, an analog of codlemone, (E,E)-8,10-dodecadien-1-ol, the sex pheromone of the codling moth, Cydia pomonella, found that the electrophysiological responses of antennae of C. pomonella males to codlemone were lower for analog-treated males, although only when higher dosages (>50 μg) of the analog were used.…”