Monitoring Amyelois Transitella Males and Females with Phenyl Propionate Traps in Almonds and Pistachios

DOI: 10.1111/j.1570-7458.2009.00925.x Monitoring Amyelois transitella males and females with phenyl propionate traps in almonds and pistachios Charles S. Burks1*, Bradley S. Higbee2,L.P.S.Kuenen1 &DavidG.Brandl1 1USDA-ARS, San Joaquin Valley Agricultural Sciences Center, Parlier, CA, USA, and 2Paramount Farming Company, Bakersfield, CA, USA Accepted: 14 September 2009 Key words: navel orangeworm, California, semiochemical, female attractant, Lepidoptera, Pyralidae, glass dispenser, Prunus dulcis, Pistacia vera Abstract We examined phenyl propionate as an attractant for trapping navel orangeworm, Amyelois transitella (Walker) (Lepidoptera: Pyralidae) adults, with the objective of developing a method of trapping both sexes more effectively than with almond meal. Two initial experiments maximized the total number of adults captured using phenyl propionate released from glass vials with cotton wicks. A third experiment compared the numbers of males and females captured using these glass dispensers in either bucket or sticky traps. The glass vial dispensers captured more adults than 0.1% phenyl propionate in water (as both attractant and killing agent), and far more adults were captured with glass vial phenyl propionate dispensers than with almond meal. On rare occasion, the glass vial dispensers captured as many adults as traps baited with virgin females, but usually phenyl propionate in glass vials captured fewer adults than virgin-baited traps. Glass vial phenyl propionate dispensers were equally effective in sticky traps or bucket traps. The majority of females captured were mated, and the proportion of males captured increased over time within flights (generations). We conclude that phenyl propionate released from glass vials captured A. transitella adults more effectively than currently available options, and will be useful in research projects where capturing intact adults and comparing mating status are important. Developing a cost-effective phenyl propionate-based alternative to the egg traps currently used for commercial monitoring will be more difficult. Zalom et al., 2009). When chemical control is necessary, Introduction trapping data are used in conjunction with degree day The navel orangeworm, Amyelois transitella (Walker) models to time application targeting the overwintering (Lepidoptera: Pyralidae), is highly polyphagous and a generation (first flight, March–May) and⁄ or the succeed- primary pest of almonds, Prunus dulcis (Mill.) D.A. ing generation (second flight, June–July) (Zalom et al., Webb (Rosaceae), and pistachios, Pistacia vera L. 2009). In pistachios these data and models are used to time (Anacardiaceae) (Bentley et al., 2009; Zalom et al., 2009). treatment against the third flight (Bentley et al., 2009). It is also economically important in walnuts, Juglans regia Mating disruption has recently been registered for use L. (Juglandaceae) (Pickel et al., 2009), and figs, Ficus carica against A. transitella in almonds, pistachios, walnuts, and L. (Moraceae) (Burks & Brandl, 2005). In the southern San figs. High-volume timed release aerosol dispenser (Puffer Joaquin Valley (CA, USA), A. transitella is more abundant NOW; Suterra, Bend, OR, USA) is the only dispenser type in mature pistachios compared to almonds (Burks et al., available. Data to date suggest that, in established orchards, 2008), and it is multivoltine in both crops. mating disruption is more likely to provide greater benefit Management of A. transitella damage in almonds and in almonds then in pistachios (Higbee & Burks, 2008). pistachios has long emphasized cultural practices, supple- Various monitoring methods have been used in mented with insecticides, if necessary (Bentley et al., 2009; research on control of A. transitella damage, but the egg trap is currently the standard commercial tool for monitoring and timing treatments (Rice, 1976; Rice et al., 1984; *Correspondence: Charles S. Burks, USDA-ARS, 9611 S. Riverbend Van Steenwyk & Barnett, 1985; Kuenen et al., 2008). While Avenue, Parlier, CA 93648, USA. E-mail: [email protected] attractive blends of pheromone components have been No Claims to Original US government works Entomologia Experimentalis et Applicata 133: 283–291, 2009 Journal compilation Ó 2009 The Netherlands Entomological Society 283 284 Burks et al. identified for A. transitella (Leal et al., 2005; Millar & Kue- listed previously are found widely in nature and can origi- nen, 2005), incorporating these components into a lure nate from plant breakdown products (Diaz et al., 1998), that is attractive for more than one or two nights has pro- but we are unaware of any study associating phenyl propi- ven difficult (LPS Kuenen, pers. obs.). Unmated females onate specifically with A. transitella host material. Phenyl are therefore still used as a pheromone source for monitor- propionate has also been demonstrated as an attractant for ing this species for experimental purposes (Burks et al., Phyllophaga spp. (Crocker et al., 1999). A similar phenolic 2008; Higbee & Burks, 2008). Traps containing almond compound, 2-phenylethanol, has been found in fungus- meal and almond oil (used as oviposition attractant in egg infested commodities and shown to be attractant to Ory- traps) have also been shown to capture A. transitella zaephilus surinamensis (L.) (Pierce et al., 1991) and Ecto- females, but they are not used commercially because egg myelois ceratoniae (Zeller) (Cosse´ et al., 1994), which are traps are cheaper, easier to use, and do not share the prob- also scavenger species associated with dried fruit and lem of capturing species resembling A. transitella (Rice stored products. et al., 1976). The objectives of the current study were to: (1) compare Mating disruption treatments targeted against other the effectiveness of phenyl propionate as an attractant Lepidoptera have, in some cases, resulted in reduced dam- when used either in a water trap as a 0.1% aqueous solu- age despite the presence of mated females in the treatment tion or when released from a saturated cotton wick; and plot (Rice & Kirsch, 1990; McLaughlin et al., 1994; Agnello (2) to compare, in almonds and pistachios, the number, et al., 1996; Kovanci & Walgenbach, 2005; Knight, 2006, sex, and mating status of A. transitella captured with phe- 2007). It has been therefore proposed that reduced moth nyl propionate and with almond meal. Traps baited with fecundity due to either delayed or decreased multiple mat- virgin females or with almond meal were used to provide ing, caused by mating disruption, is an important factor in estimates of relative abundance A. transitella. its efficacy in some species (Vickers, 1997; Jones & Aihara- Sasaki, 2001; Knight, 2006, 2007). For investigation of this Materials and methods effect, compounds attractive to both sexes and whose attractiveness is not completely eliminated by pheromone Two experiments were conducted to compare the number permeation have proven useful; e.g., terpinyl acetate bait of adults captured using phenyl propionate (propionic traps for Graphilita molesta (Busck) (Rice & Kirsch, 1990; acid phenyl ester, CAS 637-24-4; TCI America, Portland, Kovanci & Walgenbach, 2005) and (E,Z)-2,4-decadienoate OR, USA) dispensed using either as a 0.1% (wt ⁄ vol) solu- (pear ester) for Cydia pomonella L. (Knight, 2006, 2007). tion, as reported previously (Price et al., 1967), or using a Phenyl propionate is a possible candidate for such a role in glass vial dispenser containing neat phenyl propionate and characterizing the response of A. transitella to mating dis- a cotton wick. A third experiment compared, between ruption (Price et al., 1967). almond meal and phenyl propionate dispensed from glass In some cases mating disruption has been implemented vials, the number and sex of adults and mating status of over the entire portion of the year that the target pest is females. In each of these experiments wing traps baited active, whereas in other cases it has been targeted against with virgin females were used as an index of seasonal abun- selected generations in a multivoltine pest (Rice & Kirsch, dance. An overview of lures and trap types used in these 1990; Vickers, 1990; Trimble et al., 2001; Atanassov et al., three experiments is provided in Table 1. 2002; Pickel et al., 2002). As the number of spermato- Experiment 1 was conducted in March and April 2004 phores per A. transitella female varies over the growing in an orchard of Kerman pistachios in Madera County, season (Landolt & Curtis, 1991), examining the abundance CA, USA (37°00¢N, 119°57¢W). This experiment com- of mated females and the number of spermatophores per pared the effect of wick length in glass vial phenyl propio- females in the presence of mating disruption would be use- nate dispensers, and compared these dispensers with ful for assessing its effect against A. transitella at various phenyl propionate in a 0.1% (wt ⁄ vol) solution in water times of the year. which served as both attractant and a killing solution. A Phenyl propionate is one of several compounds demon- completely randomized design was used to compare six strated as attractants for A. transitella (Price et al., 1967), treatments (Table 1). Treatments were randomly assigned but its role in the chemical ecology of this species has not to trees ca. 50 m apart within one of five orchard rows ca. been established. Phenyl propionate, ethyl phenylacetate, 50 m apart. Traps were suspended from branches at and phenyl isobutyrate captured A. transitella males and 1.5–2 m above the ground, approximately

Load more