Progress 09/01/07 to 08/31/10
Outputs
OUTPUTS: Field experiments evaluating the efficacy of pheromone blends and a behavioral antagonist for dogwood borer mating disruption and the possible behavioral mechanism of disruption were conducted in commercial apple orchards in North Carolina, Virginia and West Virginia from 2008 - 2010. New synthetic pathways for producing scaled-up quantities of highly pure (Z,Z)-3,13-octadecadienyl acetate (ODDA), the major component of the three-component dogwood borer sex pheromone, were investigated at Beltsville, MD from 2008 - 2010. Treatments in the 2008 mating disruption trial included; 1) (Z,Z)-3,13-ODDA, 2) (Z,Z)-3,13 plus (E,Z)-2,13-ODDA, 3) (Z,Z)-3,13 plus (E,Z)-2,13 and (Z,E)-3,13 ODDA, 4) (E,Z)-3,13-ODDA (the antagonist), 5) lesser peachtree borer pheromone (ca. 70% (E,Z), 30% (Z,Z)-3,13-ODDA) and 6) untreated control. In 2009, treatments included; 1) unpurified (Z,Z)-3,13-ODDA, 2) (E,Z)-3,13-ODDA, 3) lesser peachtree borer pheromone and 4) untreated control. In 2010, purified (Z,Z)-3,13-ODDA was added to the treatments evaluated in 2009. The lesser peachtree borer blend was formulated in the commercial rope dispenser (Isomate LPTB) containing 50 mg of pheromone while the remaining treatments were formulated in polyethylene vial dispensers, each containing 50 mg of product. Dispensers were deployed at 25 per plot in non-replicated, ca. 0.1 ha plots in the interior of 1 ha plots in each orchard. Two delta style pheromone traps were deployed in the center of each 0.1 ha plot. One trap was baited with a rubber septum lure containing 1 mg of the three-component dogwood borer pheromone blend and the second was baited with a pheromone dispenser of the corresponding mating disruption treatment. Treatments were deployed for 5-7 weeks and the number of male dogwood borer captured in each trap was recorded weekly. To examine the possible mechanism by which these dispensers disrupted male response, their relative attractiveness to male dogwood borer was compared in each state. Four replicates of each treatment, including a rubber septum loaded with 1 mg of the three-component pheromone, were deployed in delta style pheromone traps separated by 25 m within trap rows. In 2009, traps were rotated among positions within each row of traps at weekly intervals for five weeks, while in 2010 the treatments were deployed in a Latin Square design and were not rotated over the five-week trapping interval. Results from project field studies were presented to apple growers at in-season production meetings in North Carolina and Virginia. A poster titled "A practical one-pot chemical synthesis of (3Z)-hexene-1,6-diol as a building block to prepare high geometric purity insect pheromone component" was presented at the 2008 meeting of the Entomological Society of America, Reno NV. An invited presentation titled "How field observations can lead to potential solutions: Development of behaviorally-based management strategies for the dogwood borer in apple orchards" was given at Cornell University in 2008. PARTICIPANTS: A) PI - J.C. Bergh, T.C. Leskey, J.F. Walgenbach, A. Zhang B) Technical Support - Jean Engelman, Starker Wright, Tori Hancock, Monica Schiessl, Nicole Orengo, June Nie, Lisong Hu C) Summer Interns - John Cullum, Rebecca Posa, Jessica Goods, Kent Thomas, Thomas Madden, Erin Spinks, Daniel Calabrese, Jeffrey Russin, John Driessnack, Rebecca Shim, Courtney Bouldin D) Collaborators - Orr Brothers Orchards, Fruit Hill Orchards, Silver Creek Orchards, Snapp Orchards, North State Farms, Apple Ridge Packers TARGET AUDIENCES: Our primary target audiences were apple growers and county extension agents in NC, VA and WV. Researchers were targeted via presentations at the Entomological Society of America and Cornell University. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
To obtain highly pure (Z,Z)-3,13-octadecadienyl acetate (>99%), many different synthetic pathways were designed and attempted and we conclude that 99.0% stereoisomeric purity is the best that can be realistically and consistently achieved. We successfully modified a previously reported synthetic method that suffered from low overall yield and was ill-suited for large preparations. Yield was increased significantly; we obtained 2.5g of (ZZ)-3,13-ODDA of 95.5% purity and 1.5g of 99.7% purity. These findings may prove important to large scale, commercial synthesis of this molecule when its isometric purity influences pheromone efficacy for monitoring and/or mating disruption of the numerous sesiid pests that utilize (Z,Z)-3,13-ODDA as a pheromone component. In 2008, presumed contamination of monitoring lures during shipment to investigators rendered the data from that season inconclusive. Our 2009 and 2010 studies examining the possible mechanism(s) of mating disruption via comparative evaluations of male captures in traps baited with mating disruption dispensers suggested that treatments including (Z,Z)-3,13-ODDA likely affect male mate-finding via competitive attraction; many more males were captured in traps baited with (Z,Z)-3,13-ODDA in vial dispensers or with the three-component pheromone blend in rubber septa than in those baited with (E,Z)-3,13-ODDA in vial dispensers or LPTB pheromone ropes. However, in mating disruption plots, male dogwood borer response to traps containing the three-component pheromone lure was significantly reduced, compared with the untreated controls, by all treatments, including the pure antagonist, (E,Z)-3,13-ODDA and off-ratio blends that included the antagonist, represented by the LPTB ropes and the impure (Z,Z)-3,13-ODDA formulation. In fact, captures in monitoring traps were most consistently reduced when Isomate LPTB ropes were used as the disruption treatment. In combination, the results from our disruption mechanism and mating disruption studies indicate that formulations containing the antagonist alone or in off-ratio blends affect the mate-finding behavior of male dogwood borer via mechanisms that remain poorly understood but that do not involve competitive attraction. While our protocol did not include assessments of the effect of mating disruption treatments on larval dogwood borer populations, the profound disruption of male response to monitoring traps by all treatments suggests that dogwood borer is a highly likely candidate for the successful use of this management tactic. Furthermore, its disruption by the antagonist alone and by off-ratio blends appears to preclude the necessity for commercial producers of mating disruption formulations to incur the considerable expense associated with generating highly pure (Z,Z)-3,13-ODDA in large quantities. One such company is currently evaluating the market potential for a dogwood borer mating disruption formulation and a product may be available within one to two years.
Publications
- No publications reported this period
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Progress 09/01/08 to 08/31/09
Outputs
OUTPUTS: In 2009, the effect of three mating disruption formulations on the capture of male dogwood borer in pheromone traps was assessed in 0.1 ha plots in commercial apple orchards (1 per state) in West Virginia, Virginia and North Carolina. To overcome the apparent issues with and effects of cross-contamination of dispensers and lures that we experienced in 2008, extra care and procedures were implemented during their preparation, shipment and deployment in 2009. The dispensers of each formulation contained 50 mg of pheromone and included (Z,Z)-3,13-ODDA (containing less than 1% (E,Z)-3,13-ODDA) and (E,Z)-3,13-ODDA in polyethylene vials and Isomate LPTB (lesser peachtree borer) "rope" dispensers, deployed at a rate of 250 dispensers/ha. In West Virgina, six untreated control plots were interspersed with single plots treated with each of the disruption formulations. In Virginia and North Carolina, one plot per orchard was treated with each disruption formulations and a fourth plot served as the untreated control. Between late June (WV) and late July (VA and NC), a single delta style pheromone trap baited with a red rubber septum containing 1 mg of purified dogwood borer pheromone was deployed in the center of each plot and the capture of male dogwood borer was recorded weekly through early to mid October. Between late July and mid-August, a second pheromone trap was deployed in the center of each plot, baited with a dispenser of the corresponding mating disruption formulation and monitored weekly through the end of the study. A companion study in 2009 compared the capture of male dogwood borer in delta style traps deployed in a commercial apple orchard in each state. Traps were baited with a dispenser containing each of the mating disruption formulations or with a red rubber septum containing 1 mg of dogwood borer pheromone. Each treatment was represented once in each of four rows within the orchard and deployed in a Latin square design. Traps were separated by at least 25 m within rows and trap rows were separated by several buffer rows. The number of male dogwood borer captured was recorded weekly for 4-6 weeks in between late June and August. Research on pathways for synthesizing the main dogwood borer sex pheromone, (Z,Z)-3,13-ODDA, with high stereoisomeric purity (greater than 99.5%) continued in Beltsville, MD in 2009. To generate a sufficient amount (grams) of highly pure (Z,Z)-3,13-ODDA, several grams of the critical moiety 1 of molecule, containing the sensitive double bond at 3 position with Z geometry from cyclic precursor, 1,4-cyclohexadiene and more than 25 grams of moiety 2 were prepared. In addition, five different coupling reactions were been conducted for scale-up reaction. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
In orchards not treated with mating disruption dispensers, similar numbers of male dogwood borer were captured in traps in West Virginia that were baited with polyethylene vials containing 50 mg of (Z,Z)-3,13-ODDA and with rubber septa containing 1 mg of the 3-component sex pheromone, while in North Carolina and Virginia, traps baited with rubber septa captured more moths than those baited with the vials. In all states, very few moths were captured in traps baited with vials containing (E,Z)-3,13-ODDA or with LPTB ropes. In 0.1 ha orchard plots treated with mating disruption dispensers, fewest moths were captured in traps deployed in plots treated with LPTB ropes. Mating disruption dispensers containing (Z,Z)-3,13-ODDA virtually eliminated captures in traps baited with rubber septa lures Virginia, but not in West Virginia or North Carolina. In all states, treatment of plots with dispensers containing (E,Z)-3,13-ODDA did not result in the elimination of captures. Captures in traps deployed in non-disrupted plots were several to many times greater than in all disrupted plots. Continued assessments of the effects of these treatments will be conducted in 2010 and final interpretation of treatment effects will await the results from further testing. The coupling reaction using moiety 1 with triflate functional group and Grignard moiety 2 only resulted in highly pure (Z,Z)-3,13-ODDA (greater than 99.6%) at the milligram level. The five different coupling reactions that were conducted for scale-up reaction were not successful, although the coupling reaction using the Grinard moiety 2 and bromide moiety 1 catalyzed by copper showed promising results and we anticipate the synthesis of pure (Z,Z)-3,13-ODDA in our scale-up reaction. CBC America, Inc. has applied to license the USDA/Virginia Tech dogwood borer pheromone patent and is deliberating on commercializing the product for dogwood borer mating disruption.
Publications
- No publications reported this period
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Progress 09/01/07 to 08/31/08
Outputs
OUTPUTS: Experiments comparing the effect of mating disruption formulations for dogwood borer (Objective 1, Experiment 1) were conducted in 0.1 ha sub-plots in commercial orchards in West Virginia, Virginia and North Carolina in 2008. The formulations evaluated in each orchard were deployed at a rate of 250 per ha and included: (1) (Z,Z)-3,13-ODDA alone (the main component of the dogwood borer sex pheromone, (2) 96:4 (Z,Z)-3,13-ODDA:(E,Z)-2,13-ODDA blend, (3) complete (3-component) pheromone blend, (4) attraction antagonist (E,Z)-3,13-ODDA, (5) attraction antagonist blend (Isomate LPTB dispensers) and (6) untreated control. Two delta style traps deployed in each sub-plot were baited with a lure containing the complete blend of dogwood borer sex pheromone or a dispenser containing the respective mating disruption formulation. Preliminary observations on the effect of the formulations on the mating success of pairs of moths held in screened cages (Objective 1, Experiment 2) were conducted in the West Virginia orchard by USDA and Virginia Tech project personnel in August. The response of male dogwood borer to replicated traps baited with each of the dispensers described above was evaluated in commercial apple orchards in Virginia, West Virginia and North Carolina that were not treated with the respective mating disruption formulations (Objective 1, Experiment 2). A Research Associate employed in May, 2008 continued our research on the development of a new synthetic pathway for producing highly pure (Z,Z)-3,13-ODDA (Objective 2). PARTICIPANTS: Project Director: Chris Bergh, Associate Professor of Entomology, Virginia Tech Alson H. Smith, Jr. Agricultural Research and Extension Center, Winchester, VA Project Investigator: Tracy Leskey, Research Scientist, USDA Appalachian Fruit Research Station, Kearneysville, WV Project Investigator: James Walgenbach, Professor of Entomology, Mountain Horticultural Crops Research and Extension Center, Fletcher, NC Project Investigator: Aijun Zhang, Research Scientist, USDA ARS, Beltsville, MD Project Cooperator: Lisong Hu, Research Associate, USDA ARS, Beltsville, MD TARGET AUDIENCES: Commercial apple producers, tree fruit entomologists and Cooperative Extension Service agents in the eastern USA and Canada. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Results from our mating disruption and dispenser/lure attractiveness trials were highly inconsistent among locations. We believe that several factors adversely impacted the reliability of the 2008 data and confounded our ability to interpret the results. First, since the conventional method for purifying (ZZ)-3,13-ODDA is extremely impractical for generating the amount of compound needed, requiring large volumes of solvent to produce a small amount of pure material, our mating disruption dispensers contained some of the (EZ)-3,13-ODDA as impurity. This may or may not have influenced our data but was the only available option for the 2008 season. Most importantly, it appears that leakage of pheromone from the mating disruption dispensers into the polyethylene bags containing each treatment during shipment from Beltsville to each project investigator contaminated the monitoring lures. In the mating disruption experiment, we believe that this translated to moth captures in non-disrupted control sub-plots (4 per orchard) that were highly variable among sub-plots within each orchard and to misrepresentation and inconsistency of the effects of the mating disruption treatments on moth captures. This lure contamination (and potentially cross-contamination of dispensers) also likely impacted the comparison of lure/dispenser attractiveness in the orchards without mating disruption. Finally, we believe that our 0.1 ha mating disruption sub-plots may have been insufficient to reveal true treatment effects, especially with respect to our preliminary observations of moth mating behavior in screened cages within each mating disruption plot. Nevertheless, our behavioral observations did reveal that this approach should provide valuable information on treatment effects in upcoming seasons, in which we will increase the size of the mating disruption sub-plots to 0.2 ha per treatment. Research on the development of a synthetic pathway that will yield highly pure (Z,Z)-3,13-ODDA gave very promising results in 2008. To prepare enough (Z,Z)-3,13-ODDA with high purity (>99.5%) a method that uses a cyclic precursor to elaborate the sensitive double bond was modified, yielding a product that contained only 0.21% (EZ)-isomer, with 70% yield. Our goal is to scale up this reaction to produce a large quantity of pure (Z,Z)-3,13-ODDA.
Publications
- No publications reported this period
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