Rhagoletis Indifferens Research Articles

Captures of <I>Rhagoletis indifferens</I> (Diptera: Tephritidae) and Nontarget Insects on Red Spheres Versus Yellow Spheres and Panels

Sticky red spheres can be used to capture western cherry fruit fly, Rhagoletis indifferens Curran (Diptera: Tephritidae), but red spheres have not been definitively shown to be more attractive than yellow traps. The objective of this study was to compare fly captures on ammonia-baited red spheres and yellow spheres and panels so that sensitive detection traps for fly management can be identified. Nontarget insects could interfere with fly captures, so weights of nontarget insects on traps were also determined. Yellow spheres and panels generally caught more flies than red spheres. More males than females were caught on nearly all red and yellow traps. Saffron Thread, Marigold, Sunny Summer, and Yam Yellow spheres and panels were bright yellow and generally caught more flies, especially females, than Cherry Cobbler Red or Tartar Red spheres. Twenty Carat Yellow and Glorious Gold spheres and panels were less bright and caught fewer flies than bright yellow traps and similar numbers of flies as Tartar Red spheres, respectively. Dry weights of nontarget insects on at least one yellow trap type were greater than on red spheres in only 4 of 10 tests. Results show that bright yellow spheres and panels capture more R. indifferens than red spheres and do not consistently capture greater amounts of nontarget insects than red spheres, suggesting that they should be used instead of red spheres for detecting this fly.

DEVELOPING A NEW BAIT FOR SPOTTED-WING DROSOPHILA IN ORGANIC CHERRY PRODUCTION

Studies conducted at the USDA Laboratory in Wapato, WA and at Oregon State University were initiated in 2011 to improve the efficacy of an organically-certified formulation of the insecticide spinosad (Entrust®) for control of the spotted wing drosophila, Drosophila suzukii. Our initial approach was to evaluate the possible benefits of adding a bait composed of brown sugar and compressed bread yeast, Saccharomyces cerevisiae. A direct comparison of the sugar-yeast bait with the protein-based baits, GF-120® and Nu-Lure®, in laboratory tests showed that it was more effective than either commercial product. We found that fly mortality at 2 and 6 h significantly increased throughout the season with the addition of the sugar-yeast bait. In particular, the addition of the sugar-yeast bait to Entrust increased fly mortality 4-fold in early-season bioassays with green and yellow cherries. While the mean numbers of eggs laid and larval infestations of cherry was reduced (50%) with the addition of the sugar-yeast bait, these differences were not significant. Studies are continuing in 2012 with a new yeast candidate that is an effective biofungicide combined with a higher concentration of sugar that may be an effective repellent of birds. The potential of this bait to improve control of the western cherry fruit fly, Rhagoletis indifferens is also being evaluated.

Influence of Media Type and Moisture on Adult Development and Pupal Mortality inRhagoletis indifferens(Diptera: Tephritidae)

The influence of media type and moisture on adult development and pupal mortality in western cherry fruit fly, Rhagoletis indifferens Curran (Diptera:Tephritidae), was assessed using the pupal-adult and the larval-pupal stage. Inside containers, a higher percent of flies that emerged from dry loam was deformed (44.2%, 1-cm-depth loam; 84.4%, 5-cm-depth loam) than flies from 16% moist loam and dry and 16% moist lab soil (peat moss-sand mix) (0-14.9%). Percent of flies deformed from dry sand (22.1%, 1-cm depth; 49.5%, 5-cm depth) was greater than from 16% moist sand and dry and 16% moist peat moss (0-10.5%). Percents of flies deformed from 8% moist loam, lab soil, sand, and peat moss (0-5.8%) did not differ. Pupae suffered higher mortality at 7 and 14 d after larvae were dropped onto dry loam and dry sand (68.2-94.0%) than dry lab soil and dry peat moss (3.0-53.0%); respective mortalities at 21 and 28 d were similar (81.3-96.0 versus 64.7-97.9%). Pupal mortality in moist media was lower (0.5-40.3%) than in dry media. In outdoor tests, pupal mortality was also higher in dry loam than other dry media. In nature, 60.9% of pupae in dry sandy loams in late summer were dead. Results suggest R. indifferens has not yet evolved to fully cope with dry soils and that pupation in media with traits similar to those of peat moss or a peat moss-sand mix could reduce negative effects of dry environments on fly survival.

Genetic Identification of an Unknown <I>Rhagoletis</I> Fruit Fly (Diptera: Tephritidae) Infesting Chinese Crabapple: Implications for Apple Pest Management

The apple maggot, Rhagoletis pomonella (Walsh) (Diptera: Tephritidae), is a serious introduced quarantine pest in the apple (Malus spp.)-growing regions of central Washington and Oregon. In August 2011, seven fly larvae of unknown origin were discovered infesting fruit of an exotic Chinese crabapple, Malus spectabilis (Aiton) Borkhausen, in Kennewick, Benton County, WA. If confirmed, Chinese crabapple would have represented a new host for R. pomonella in Washington and triggered quarantine measures in a surrounding three-county region of the state. Here, we establish, based on five microsatellite loci, the identity of the crabapple-infesting larvae as the western cherry fruit fly, Rhagoletis indifferens Curran, representing a new host record for the fly. Morphological analysis of six flies reared to adulthood confirmed the genetic identification. The results demonstrate the utility of integrating rapid genetic identification methods with field surveys of economic pests, which decreased detection times by months, and avoided enacting costly quarantine measures that saved local and federal bodies > US$0.5 million in monitoring, inspection, and control costs. We discuss current ongoing efforts to develop rapid, accurate, and inexpensive on site DNA-based detection tools for R. pomonella that would have general applicability for the control of pest insects.

Niche differentiation and colonization of a novel environment by an asexual parasitic wasp

How do asexual taxa become adapted to a diversity of environments, and how do they persist despite changing environmental conditions? These questions are linked by their mutual focus on the relationship between genetic variation, which is often limited in asexuals, and the ability to respond to environmental variation. Asexual taxa originating from a single ancestor present a unique opportunity to assess rates of phenotypic and genetic change when access to new genetic variation is limited to mutation. Diachasma muliebre is an asexual Hymenopteran wasp that is geographically and genetically isolated from all sexual relatives. D. muliebre attack larvae of the western cherry fruit fly (Rhagoletis indifferens), which in turn feed inside bitter cherry fruit (Prunus emarginata) in August and September. R. indifferens has recently colonized a new host plant with an earlier fruiting phenology (June/July), domesticated sweet cherries (P. avium), and D. muliebre has followed its host into this temporally earlier niche. We tested three hypotheses: 1) that all D. muliebre lineages originate from a single asexual ancestor; 2) that different D. muliebre lineages (as defined by unique mtDNA haplotypes) have differentiated on their ancestral host in an important life-history trait, eclosion timing; and 3) that early-eclosing lineages have preferentially colonized the new sweet cherry niche. We find that mitochondrial COI and microsatellite data provide strong support for a single ancestral origin for all lineages. Furthermore, COI sequencing revealed five mitochondrial haplotypes among D. muliebre, and individual wasps possessing one distinctive mitochondrial haplotype (haplotype II) eclosed as reproductive adults significantly earlier than wasps with all other haplotypes. In addition, this early-eclosing lineage of D. muliebre is one of two lineages that have colonized the P. avium habitat, consistent with the preferential colonization hypothesis. These data suggest that D. muliebre has evolved adaptive phenotypic variation despite limited genetic variation, and that this variation has subsequently allowed an expansion of some wasps into a novel habitat. The D. muliebre system may allow for in-depth study of adaptation and long-term persistence of asexual taxa.

Invasion genetics of American cherry fruit fly in Europe and signals of hybridization with the European cherry fruit fly

AbstractThe American cherry fruit fly is an invasive pest species in Europe, of serious concern in tart cherry production as well as for the potential to hybridize with the European cherry fruit fly, Rhagoletis cerasi L. (Diptera: Tephritidae), which might induce new pest dynamics. In the first European reports, the question arose whether only the eastern American cherry fruit fly, Rhagoletis cingulata (Loew) (Diptera: Tephritidae), is present, or also the closely related western American cherry fruit fly, Rhagoletis indifferens Curran. In this study, we investigate the species status of European populations by comparing these with populations of both American species from their native ranges, the invasion dynamics in German (first report in 1993) and Hungarian (first report in 2006) populations, and we test for signals of hybridization with the European cherry fruit fly. Although mtDNA sequence genealogy could not separate the two American species, cross‐species amplification of 14 microsatellite loci separated them with high probabilities (0.99–1.0) and provided evidence for R. cingulata in Europe. German and Hungarian R. cingulata populations differed significantly in microsatellite allele frequencies, mtDNA haplotype and wing pattern distributions, and both were genetically depauperate relative to North American populations. The diversity suggests independent founding events in Germany and Hungary. Within each country, R. cingulata displayed little or no structure in any trait, which agrees with rapid local range expansions. In cross‐species amplifications, signals of hybridization between R. cerasi and R. cingulata were found in 2% of R. cingulata individuals and in 3% of R. cerasi. All putative hybrids had R. cerasi mtDNA indicating that the original between‐species mating involved R. cerasi females and R. cingulata males.

Soil moisture and relative humidity effects during postdiapause on the emergence of western cherry fruit fly (Diptera: Tephritidae)

AbstractPupae of western cherry fruit fly,Rhagoletis indifferensCurran (Diptera: Tephritidae), from Kennewick and Roslyn in Washington State, United States of America, were subjected to different soil and air moisture conditions to test the hypotheses that adult emergence from dry and moist soil is similar and is greater and occurs earlier at high than low relative humidities (RHs). Adult fly emergence from 0–57% saturated loam soil did not differ in Kennewick (64.8–75.1%) and Roslyn (81.7–86.6%) populations. Emergence did not occur from 76% saturated loam soil. In a RH experiment using dry soil, emergence of Kennewick flies was highest at 97% RH (76.8%), intermediate at 12–74% RH (66.4–69.6%), and lowest at 3% RH (58.0%). Emergence of Roslyn flies was higher at 97% RH (85.6%) than 3% (69.2%) and 12% RH (74.3%), but it did not differ from that at 33% (76.9%) and 74% RH (79.4%). Flies emerged ∼2–3 days earlier at 97% RH than at 3–12% RH. An unnaturally low RH of 3% caused more flies to be deformed than higher RHs. High emergence ofR. indifferensin dry and moist conditions likely contributes to its presence in a wide range of native and nonnative habitats.

Development of Rhagoletis indifferens Curran (Diptera: Tephritidae) in crabapple

Abstract Western cherry fruit fly, Rhagoletis indifferens Curran 1932 (Diptera: Tephritidae), was reared from naturally-infested Chinese crabapple, Malus spectabilis (Aiton) Borkhausen (Rosaceae), in Washington State, U.S.A. Pupae from Chinese crabapple were smaller than those from sweet cherry, Prunus avium (Linnaeus) Linnaeus (Rosaceae), but fecundity and longevity of flies from the two hosts did not differ. Laboratory experiments were conducted to compare larval development in crabapples and cherries. ‘Snowdrift’ crabapples (Malus × ‘Snowdrift’) did not produce pupae. Percentages of ‘Indian Magic’(Malus ‘Indian Magic’) + ‘Radiant’ crabapple (Malus ‘Radiant’) vs. sweet cherry replicates that produced pupae did not differ in two no-choice experiments (36.7 vs. 41.7% and 13.3 vs. 33.5%, respectively). In a choice experiment, the percentage of crabapple replicates that produced pupae (6.7%) was lower than that of cherry replicates (42.2%). Egg to pupal development times in crabapples (18.0–21.2 d) were lon...

Control of Rhagoletis indifferens using thiamethoxam and spinosad baits under external fly pressure and its relation to rapidity of kill and residual bait activity

Control of western cherry fruit fly (Rhagoletis indifferens Curran) using thiamethoxam in sucrose bait (sucrose only) and spinosad bait (GF-120, spinosad in a mix of sugar, protein, ammonium acetate, and other ingredients) in cherry orchards with external fly pressure and the residual activity of these baits were studied in Washington state and Utah, U.S.A., in 2010 and 2011. Thiamethoxam baits applied weekly controlled larval infestations better than spinosad bait applied weekly in one of four trials and did not differ from spinosad bait applied weekly in the remaining trials. Thiamethoxam baits applied every two weeks controlled larval infestations better than spinosad bait applied every two weeks in two of three trials, and did not differ statistically from spinosad bait applied weekly. Thiamethoxam bait that was aged on sweet cherry leaves in the field for 0, 7, 14, and 21 days killed flies more rapidly than spinosad bait that was aged for the same periods and reduced oviposition more than spinosad bait in the laboratory. Thiamethoxam bait retained activity up to 21 days of aging whereas spinosad bait lost activity after 14 or 21 days of aging. Results suggest that when there is external fly pressure, the potentiality of thiamethoxam bait to kill mature R. indifferens more rapidly than spinosad bait may not always translate to better fly control. However, when sprays are applied every two weeks, the longer residual activity of thiamethoxam than spinosad bait does appear to translate to better fly control. This study presents thiamethoxam with sucrose as a new option for an effective bait spray against R. indifferens.

Preferences by Rhagoletis indifferens (Diptera, Tephritidae) for rectangles of various yellow colours and fluorescence

AbstractSticky rectangle traps of various yellow colours and fluorescence made of cardboard were field tested against western cherry fruit fly, Rhagoletis indifferens Curran, in paired trap preference experiments in Washington state. In a first experiment that involved comparisons of Alpha Scents (proprietary paint), Fluorescent Yellow (aerosol paint), Saffron Thread and Neon Light (semi‐gloss enamel paints) traps at two sites, the best performing trap was the Saffron Thread trap. In a second experiment comparing Citrus Splash (semi‐gloss enamel paint) with Alpha Scents and with Macaw and Lemon Zest (both semi‐gloss enamel paints) traps at a third site, the Citrus Splash trap outperformed the Alpha Scents trap. The Citrus Splash trap did not differ statistically from Saffron Thread and Lemon Zest traps, even though it caught 51% more flies than the Lemon Zest trap. The Alpha Scents trap caught significantly more non‐target Diptera than Fluorescent Yellow, Neon Light and Citrus Splash traps at two of three trap sites where non‐target Diptera populations were relatively high and overall it appeared less selective than the Citrus Splash trap. Results suggest that sticky rectangle traps painted semi‐gloss enamel Saffron Thread or Citrus Splash with low fluorescence could be highly useful for detecting R. indifferens.

Distribution and phenology of Rhagoletis fausta (Osten Sacken 1877) and Rhagoletis indifferens Curren 1932 (Diptera: Tephritidae) in California

Abstract We determined the distribution of Rhagoletis fausta (Osten Sacken 1877) and Rhagoletis indifferens Curren 1932 (Diptera: Tephritidae) in California outside the state interior quarantine area. Our data confirmed the historical records of R. fausta in Alpine, Amador, El Dorado, Fresno, Kern, Mariposa, Mendocino, Modoc, Mono, Nevada, Placer, Plumas, Sierra, Tehama, Tulare, and Tuolumne counties and we trapped R. fausta for the first time in Butte, Calavaras, Glenn, Inyo, Lassen, Madera, and Yuba counties. We confirmed the historical records of R. indifferens in Amador, El Dorado, Fresno, Mendocino, Modoc, Nevada, Placer, Plumas, and Sierra counties and we trapped R. indifferens for the first time in Butte, Calaveras, Lassen, Madera, Mariposa, Tulare, Tuolumne, and Yuba counties. No R. fausta were trapped in Lake, Los Angeles, or San Bernardino counties and no R. indifferens were trapped in Alpine, Glenn, Inyo, Lake, Mono, or Tehama counties. The lower altitude at which we trapped both flies increase...

Differences in Body Size and Egg Loads of Rhagoletis indifferens (Diptera: Tephritidae) From Introduced and Native Cherries

The western cherry fruit fly, Rhagoletis indifferens Curran, infests introduced, domesticated sweet [Prunus avium (L.) L.], and tart cherries (Prunus cerasus L.) as well as native bitter cherry, Prunus emarginata (Douglas) Eaton. Bitter cherries are smaller than sweet and tart cherries and this could affect various life history traits of flies. The objectives of the current study were to determine 1) if body size and egg loads of flies infesting sweet, tart, and bitter cherries differ from one another; and 2) if any observed body size differences are genetically based or caused by the host fruit environment. Pupae and adults of both sexes reared from larval-infested sweet and tart cherries collected in Washington and Montana were larger than those reared from bitter cherries. In addition, flies of both sexes caught on traps in sweet and tart cherry trees were larger than those caught in bitter cherry trees and females trapped from sweet and tart cherry trees had 54.0-98.8% more eggs. The progeny of flies from naturally-infested sweet and bitter cherries reared for one generation in the laboratory on sweet cherry did not differ in size. The same also was true for progeny of sweet and bitter cherry flies reared in the field on bitter cherry. The results suggest that the larger body sizes of flies from sweet and tart cherries than bitter cherries in the field are caused by host fruit and not genetic factors.

Impact of Metarhizium brunneum (Hypocreales: Clavicipitaceae) on pre-imaginal Rhagoletis indifferens (Diptera: Tephritidae) within and on the surface of orchard soil

When last instar laboratory-reared Rhagoletis indifferens were allowed to pupate within non-sterile orchard soil containing incorporated Metarhizium brunneum isolate F52 conidia, a dose-related proportion died from developmental abnormalities and mycosis. When larvae entered soil superficially treated with M. brunneum, over 80% of the pupae died of developmental abnormalities.

Behavioral responses, rate of mortality, and oviposition of western cherry fruit fly exposed to malathion, zeta-cypermethrin, and spinetoram

Western cherry fruit fly, Rhagoletis indifferens Curran (Diptera: Tephritidae), is a pest of sweet and tart cherry, Prunus avium L. (L.) and P. cerasus L., respectively, in western North America. This fly is commonly controlled with spinosad bait sprays. Spotted wing drosophila, Drosophila suzukii Matsumura, is potentially a new pest of cherries in this region that could be a threat to orchards at the same time as R. indifferens. Drosophila suzukii apparently is not controlled using spinosad bait sprays, but may potentially be controlled using malathion, zeta-cypermethrin, and spinetoram. However, how well these last three materials protect fruit against reproductively mature R. indifferens is not known. In laboratory observations, R. indifferens spent the least amount of time on cherries treated with zeta-cypermethrin, possibly because of its toxicity and irritant effects. In laboratory experiments, zeta-cypermethrin killed flies more quickly than malathion and spinetoram, causing up to 100% mortality 2 h after exposure. Zeta-cypermethrin prevented all oviposition when flies walked on dried residues for 20–25 min or were directly sprayed, and then exposed to cherries with dried residues, simulating exposure of mature female flies in a treated orchard. Malathion and spinetoram reduced oviposition compared with controls, but did not prevent it, when flies contacted residues or were directly sprayed at a high volume. Results suggest zeta-cypermethrin is the most effective of the three materials at protecting cherries against mature R. indifferens and could be used in an integrated control program for it and D. suzukii.

Detection of Rhagoletis indifferens (Dipt., Tephritidae) larvae using brown sugar flotation and hot water methods

AbstractThe brown sugar flotation and hot water methods are accepted procedures for detecting larval western cherry fruit fly, Rhagoletis indifferens Curran, in sweet cherry [Prunus avium (L.) L.] and could be included in a systems approach, a combination of all steps involved in cherry production, for showing the absence of larvae in fruit. The methods require crushing cherries and then submerging them in brown sugar solution or hot water to extract the larvae. Larvae are visually detected when they float to the surface of the brown sugar solution or sink in the hot water. The objective of this study was to test the efficacy of these two methods. Both methods detected at least one larva in all 288 moderately to heavily infested cherry samples. The brown sugar flotation and hot water methods detected 89.6–94.7% and 83.0–85.9% of total larvae, respectively, from cherry samples on each of three dates. Significantly higher percentages of 1st instars were detected using the brown sugar than hot water method on two dates, of 3rd instars on one date and of total larvae on two dates. Percent detection of 3rd instars was higher than that of 1st instars using both methods. For both methods, greater percentages of split whole cherries with seeds and non‐split cherries had larvae than split whole cherries with no seeds and halved cherries. Results show that both methods were equally efficacious in detecting the presence of R. indifferens larvae in cherry samples, but brown sugar flotation was more efficacious than the hot water method in detecting a higher percentage of total larvae present and could be integrated into a systems approach for R. indifferens.

Evaluation of Yellow Rectangle Traps Coated With Hot Melt Pressure Sensitive Adhesive and Sticky Gel Against Rhagoletis indifferens (Diptera: Tephritidae)

Sticky yellow rectangle traps have been used for many years to capture Rhagoletis (Diptera: Tephritidae) fruit flies. Traditional sticky yellow traps are coated with a sticky gel (SG) that can leave residues on the hands of users. An alternative to SG on traps are hot melt pressure sensitive adhesives (HMPSAs), which are less messy. The main objective here was to evaluate two rectangle traps of two yellow colors, the Alpha Scents Yellow Card coated with HMPSA (Alpha Scents, West Linn, OR), and the Pherocon AM trap coated with SG (Pherocon; Trécé, Adair, OK), for capturing western cherry fruit fly, Rhagoletis indifferens Curran. Flies captured on both traps and held in the laboratory and field did not escape their surfaces. Flies caught on HMPSA were damaged when removed from traps without citrus solvent, whereas flies caught on SG could be removed intact without solvent. In field tests, Alpha Scents traps baited with an ammonium bicarbonate lure captured 1.4-2.2 times more R. indifferens than Pherocon traps baited with the same lure. Results of an experiment that eliminated differences in surface sticky material type, overall size, and surface sticky area between Alpha Scents and Pherocon traps suggested, although did not show conclusively, that more flies were caught on the Alpha Scents than Pherocon traps because of their different yellow color and/or lower fluorescence and not the HMPSA. Overall, the Alpha Scents trap is a viable alternative to the Pherocon trap for detecting R. indifferens.

Mortality and Oviposition of Western Cherry Fruit Fly (Diptera: Tephritidae) Exposed to Different Insecticide Baits for Varying Periods in the Presence and Absence of Food

Spinosad bait is used to control western cherry fruit fly, Rhagoletis indifferens Curran (Diptera: Tephritidae), by killing flies before they oviposit. However, effects of different insecticide baits on management of reproductively mature flies are largely unknown. Objectives here were to determine mortality and oviposition of reproductively mature R. indifferens exposed to different insecticide baits for varying periods in the presence and absence of dried yeast extract and sucrose food. Spinosad bait (spinosad in a mix of protein, sugar, and other ingredients) was compared with acetamiprid, thiamethoxam, and imidacloprid in sucrose or Nu-Lure + sucrose bait. When flies were exposed to treatments and then offered cherries, Prunus avium (L.) L., for oviposition or when they were exposed to treatments and cherries simultaneously, both thiamethoxam bait and imidacloprid bait resulted in higher mortality and lower oviposition than spinosad bait and acetamiprid bait. Exposures to thiamethoxam bait and imidacloprid bait for six and 24 h were similarly effective, but 6-h exposures to spinosad bait and acetamiprid bait were less effective than 24-h exposures. There was little difference between sucrose and Nu-Lure + sucrose baits. When food was present, thiamethoxam bait and imidacloprid bait caused greater mortality and lower oviposition than spinosad bait and acetamiprid bait, but when food was absent, patterns were less consistent. Because of its ability to kill flies sooner after it is exposed to flies when food is present or absent, thiamethoxam or imidacloprid in sucrose or Nu-Lure bait may reduce infestations in cherries more than spinosad bait when mature R. indifferens are present in orchards.

Behavioural responses by Rhagoletis indifferens (Dipt., Tephritidae) to sweet cherry treated with kaolin‐ and limestone‐based products

AbstractKaolin‐ and limestone‐based products were compared for their effects on two behavioural responses, landing and oviposition, to sweet cherry by Rhagoletis indifferens Curran (Dipt., Tephritidae). Surround (95% calcined kaolin), Cocoon (100% hydrous kaolin), Eclipse (>97% limestone) and Purshade (62.5% limestone) were studied. Overall, in choice and no‐choice tests, Surround reduced landing and oviposition more than Cocoon, Eclipse and Purshade. However, all products significantly reduced landing and oviposition compared with untreated controls. In choice tests, high fly density increased the proportion of eggs laid in cherries treated with Surround, Cocoon, or Eclipse vs. cherries that were untreated when compared with low fly density. Applications of 3% followed by 6% Surround reduced landings and oviposition more than two applications of 10% Cocoon, Eclipse, or Purshade. Surround caused higher mortality than Cocoon and Eclipse. In the field, Surround reduced production of puparia from cherries by 32.3% to 100%, depending on the trees sprayed. Surround provided the best protection for cherries against R. indifferens, but limestone‐based products potentially might be modified to be oviposition deterrents. Consideration should be given to fly densities when using particle films to protect fruit.

Analysis of single-copy, nuclear microsatellite markers from flies collected on sticky traps

Sticky traps can provide large numbers of spatially referenced samples for use in molecular ecological studies of insects. However, the adhesives used on these traps, and the methods used to clean adhesive off trapped individuals, could potentially interfere with downstream molecular analyses. Specimens captured on sticky traps have been successfully used to analyse mitochondrial or multiple-copy ribosomal DNA markers, but not single-copy nuclear markers. Furthermore, the effects of trap adhesive and cleaning protocol on the success of molecular analyses have not been explored. Here, we examine the effects of trap adhesive, sample cleaning method, and sample storage condition on DNA concentration and purity, and on the ability to amplify single-copy, nuclear microsatellite loci, using specimens of the western cherry fruit fly, Rhagoletis indifferens (Diptera: Tephritidae) captured on sticky traps in an orchard. We could extract DNA of high purity, and amplify microsatellite loci in multi-plex polymerase chain reaction (PCR), under all combinations of treatments. However, DNA yield, DNA purity and the yield of PCR products were affected by treatment, with complex interactions among trap adhesive, sample cleaning method, and storage condition. Samples that were cleaned with acetone and stored dry had the highest DNA concentration. With respect to PCR amplification, samples cleaned with Histo-clear produced much less product than those cleaned with acetone or not cleaned at all, whereas samples that were stored dry produced more PCR product than samples stored in ethanol. Insects captured on sticky traps can thus provide genetic data appropriate for molecular ecological analyses under a wide range of treatment conditions. However, potential interactions among adhesives, cleaning protocols and storage conditions suggest that any novel combination for treatment of samples from sticky traps should be tested on a small scale prior to collecting large numbers of samples for genetic studies.

Yeast Extract: Sucrose Ratio Effects on Egg Load, Survival, and Mortality Caused by Gf-120 in Western Cherry Fruit Fly (Diptera: Tephritidae)

It is unclear which ratios of yeast extract to sucrose result in maximum egg production and survival in many tephritid fruit flies. Objectives here were to determine yeast extract:sucrose ratios that maximize egg loads without compromising survival in western cherry fruit fly, Rhagoletis indifferens Curran, and their effects on mortality caused by spinosad bait (GF-120). Yeast extract:sucrose ratios of 20:80 and 30:70 maximized egg loads without reducing survival in most cases. In 1 experiment, mortality of flies with low to high egg loads exposed to fresh GF-120 for 1 or 2 h in the absence of food did not differ. In a separate experiment, egg loads were lowest in flies fed 0:100 and 1:99 diets and highest in flies fed 20:80, 30:70, and 50:50 diets. When these flies were exposed to dried GF-120 for 6 h in presence of yeast extract and sucrose, percent mortality was lower in flies fed 20:80 and 30:70 (40%) than 0:100 (69%) and 1:99 (63%) diets. In another experiment, egg loads were lowest in flies fed 0:100 and 1:99 diet and highest in flies fed 20:80 diet. When these flies were exposed to dried GF-120 for 6 h in the presence of sucrose only, percent mortality was lower in flies fed 20:80 (39%) than 0:100 (72%) and 1:99 (62%) diets. High yeast extract:sucrose ratios result in high egg loads in R. indifferens and may reduce the fly's feeding responses to GF-120, although not to the extent that the bait is rendered completely ineffective.