Gypsy Moth Sex Pheromone Research Articles

Design and Synthesis of Fluorophore-Tagged Disparlure Enantiomers to Study Pheromone Enantiomer Discrimination in the Pheromone-Binding Proteins from the Gypsy Moth, Lymantria dispar.

Fluorescent analogues of the gypsy moth sex pheromone (+)-disparlure (1) and its enantiomer (-)-disparlure (ent-1) were designed, synthesized, and characterized. The fluorescently labelled analogues 6-FAM (+)-disparlure and 1a 6-FAM (-)-disparlure ent-1a were prepared by copper-catalyzed azide-alkyne cycloaddition of disparlure alkyne and 6-FAM azide. These fluorescent disparlure analogues 1a and ent-1a were used to measure disparlure binding to two pheromone-binding proteins from the gypsy moth, LdisPBP1 and LdisPBP2. The fluorescence binding assay showed that LdisPBP1 has a stronger affinity for 6-FAM (-)-disparlure ent-1a, whereas LdisPBP2 has a stronger affinity for 6-FAM (+)-disparlure 1a, consistent with findings from previous studies with disparlure enantiomers. The 6-FAM disparlure enantiomers appeared to be much stronger ligands for LdisPBPs, with binding constants (Kd) in the nanomolar range, compared to the fluorescent reporter 1-NPN (which had Kd values in the micromolar range). Fluorescence competitive binding assays were used to determine the displacement constant (Ki) for the disparlure enantiomers in competition with fluorescent disparlure analogues binding to LdisPBP1 and LdisPBP2. The Ki data show that disparlure enantiomers can effectively displace the fluorescent disparlure from the binding pocket of LdisPBPs and, therefore, occupy the same binding site.

Effects of SPLAT® GM sprayable pheromone formulation on gypsy moth mating success

AbstractSeveral integrated pest management programs rely on the use of mating disruption tactics to control insect pests. Some programs specifically target non‐native species, such as the gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae). We evaluated SPLAT® GM, a new sprayable formulation of the gypsy moth sex pheromone disparlure, for its ability to disrupt gypsy moth mating. The study was conducted in 2006, 2007, and 2008 in forested areas in Virginia, USA. Mating success of gypsy moth females was reduced by >99% and male moth catches in pheromone‐baited traps by >90%, in plots treated with SPLAT® GM at dosages ranging from 15 to 75 g of active ingredient (a.i.) ha−1. Dosage‐response tests conducted in 2008 indicated that SPLAT® GM applied at a dosage of 7.5 g a.i. ha−1 was as effective as a 15 g a.i. ha−1 dosage.

Synthesis and biological activity of conformationally restricted gypsy moth pheromone mimics

The design and synthesis of a series of conformationally constrained mimics of gypsy moth sex pheromone, (+)-disparlure (7 R,8 S)-2-methyl-7,8-epoxyoctadecane, are described. The core structure of the mimics is derived from 5-(2′-hydroxyethyl)cyclopent-2-en-1-ol. Substituent optimization of the analogs was accomplished through the synthesis of mini-libraries and pure individual compounds, followed by electrophysiological experiments with male gypsy moth antennae. The electroantennogram results show that the analogs elicited weak to no antennal responses themselves. There was a clear structure–activity pattern for odorant activity, with ethyl substituents being best. Further, when puffed simultaneously with the pheromone, some of the compounds gave a significant enhancement of the antennal depolarization, indicating an additive or synergistic effect. A pure pheromone stimulus following a mixed compound/pheromone stimulus was generally not affected, with two exceptions: one compound enhanced and another inhibited a subsequent stimulus. The compounds also prolonged the stimulation of the antenna, which manifested itself in widened electroantennogram peaks. We tested the hypothesis that this prolonged stimulation may be due to the stabilization of a particular conformer of the pheromone-binding protein (PBP). Compounds that caused PBP2 to adopt a similar conformation than in the presence of pheromone also caused peak widening. This was not the case with PBP1.

Gypsy moth mating disruption in open landscapes

Abstract1 Aerial applications of Disrupt II, a plastic laminated flake formulation containing a racemic form of the gypsy moth sex pheromone, disparlure, achieved > 99% reduction of mating among females on individual, isolated trees surrounded by an area cleared of trees.2 These results support the use of mating disruption to eradicate isolated gypsy moth populations in open landscapes, such as parks, residential areas and commercial settings.3 Mating success in both treated and untreated areas varied with the initial distance between males and females. When the initial distance between males and females was < 5 cm in an area receiving a dosage of 37.5 g of racemic disparlure per ha, mating success was reduced by 27% compared with a similar deployment in an untreated area. Mating was eliminated in areas treated at the same dosage when males and females were initially deployed 1 m apart but on separate trees.4 This suggests that mating disruption may not be an effective tactic for gypsy moth eradication in cases where the infestation is concentrated on a small number of trees and males and females are in close proximity in space and time.

Effects of the 3M™ MEC Sprayable Pheromone® formulation on gypsy moth mating success

AbstractThe study was conducted during 2000, 2001, 2003 and 2004 in forested areas in Virginia, USA to evaluate the 3M™ MEC‐GM Sprayable Pheromone® formulation of the gypsy moth sex pheromone, disparlure, for its ability to disrupt mating in gypsy moth, Lymantria dispar (Lep.: Lymantriidae). Both mating success of gypsy moth females and male moth catches in pheromone‐baited traps were significantly reduced in plots treated with the 3M™ MEC‐GM formulation at dosages ranging from 15 to 75 g of active ingredient/ha. However, the 3M™ MEC‐GM formulation reduced trap catch to a lesser extent than did the currently registered Hercon Disrupt® II plastic flakes used as a positive control and applied at similar or lower dosages. Furthermore, the effectiveness of the 3M™ sprayable formulation declined through time, so that by the end of the male flight season, male moth catches in traps were significantly higher than in plots treated with Hercon plastic flakes. Based on the reported results, 3M™ MEC‐GM Sprayable Pheromone® formulation was never integrated into the operational treatment projects of USDA Forest Service Cooperative Slow‐the‐Spread of the Gypsy Moth management programme.

Persistent effects of aerial applications of disparlure on gypsy moth: trap catch and mating success

AbstractIn forest plots treated aerially with a plastic laminated flake formulation (Disrupt® II) of the gypsy moth sex pheromone disparlure to disrupt gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae), mating was monitored the year of treatment and 1–2 years after treatment to determine the effects of the treatment on suppression of trap catch and mating success. In the year of treatment, there was a greater than 95% reduction in trap catch and a greater than 98% reduction in mating success compared to controls. One year after treatment at a dosage of 37.5 g active ingredient (a.i.) ha−1, trap catch was reduced by 46–56% and mating success was reduced by 60–79%. Both trap catch and mating success were significantly reduced compared to controls in plots treated 1 year previously at 15 g a.i. ha−1. Trap catch, but not mating success, was significantly reduced 2 years after treatment at 37.5 g a.i. ha−1. The efficacy of mating disruption (MD) treatments in the Slow‐the‐Spread of the Gypsy Moth program was significantly reduced 2 years compared to 1 year after treatment. No such reduction was observed in plots treated with aerial applications of Bacillus thuringiensis kurstaki. The higher apparent efficacy of MD treatments 1 year after application may result to some extent from the suppression of moth capture in pheromone traps from the persistent effects of the previous year's treatment.

Effects of intentional gaps in spray coverage on the efficacy of gypsy moth mating disruption

Abstract: The study was conducted during 2001 and 2002 in forested areas in Virginia, US to examine the effects of gaps in coverage of pheromone on gypsy moth, Lymantria dispar (L.) (Lep., Lymantriidae), mating disruption. Gypsy moth male moth catches in pheromone‐baited traps were significantly reduced in plots treated with the gypsy moth sex pheromone, disparlure, at an overall application rate of 37.5 g of active ingredient (AI)/ha but with untreated gaps of 30 or 90 m between 30‐m wide treated swaths. In one of the two plots with 90 m gaps, significantly more males were captured in traps in the untreated areas compared with the treated areas within the plot. However, in another plot, significant differences in trap catches between treated and untreated areas were not observed. No difference in male moth catches in the pheromone‐baited traps was observed between treated and untreated areas within the plots treated with 30 m gaps. Female mating success did not differ significantly between treated and untreated areas within the one plot in which it was measured. These results suggest that it may be possible to lower costs associated with gypsy moth mating disruption applications by alternating treated and untreated swaths, which would reduce flight time and fuel costs, without a reduction in efficacy.

A short and efficient synthesis of (+)-disparlure and its enantiomer

A short and highly efficient approach was applied for the total synthesis of the gypsy moth sex pheromone (+)-disparlure and its enantiomer from isopropylidene D- and L-erythrose, using a common strategy.

An Efficient Enantioselective Synthesis of (+)-Disparlure.

Synthesis of (+)-disparlure, 1, the sex pheromone of gypsy moth (Lymantria dispar), commenced from cis-vinyl epoxide 4 which was prepared by our asymmetric chloroallylboration in 99% de and 94% ee. Hydroboration of 4 using dicyclohexylborane in THF, followed by sodium perborate oxidation gave a crystalline cis-3,4-epoxy alcohol 3 whose enantiomeric purity was enhanced by recrystallization. Conversion of 3 to (+)-disparlure was via alkylation of the tosylate. (+)-Disparlure was produced in four steps with an overall yield of 27% and >/=99.5% ee.

Comparative efficacy of two controlled‐release gypsy moth mating disruption formulations

AbstractThe effects of aerial applications of the gypsy moth sex pheromone, disparlure, on mating disruption and suppression of growth of populations of the gypsy moth, Lymantria dispar (L.), were investigated. Two formulations of disparlure, plastic laminate flakes applied in a single application and polymethacrylate beads applied in two applications, were compared in two separate tests conducted in 1993 and 1994. The beads were applied in two applications spaced 2 weeks apart because preliminary tests had indicated that they released pheromone too rapidly to maintain adequate emission rates throughout the period of male flight. In 1993, the flakes were applied at a rate of 50 g a.i./ha, and the beads were applied at a rate of 15 g a.i./ha for each application. In 1994, the flakes were applied at a rate of 75 g a.i./ha and the beads were applied at rates of 32.5 and 42.5 g a.i./ha for the two applications. Beads with larger average particle size were used in 1994 to prolong disparlure release. The treatments applied in 1993 resulted in >97% reduction in mating and >82% suppression of population growth in the following year. Because of a 1995 collapse of gypsy moth populations in the vicinity of the tests, reliable population growth data were not available for the treatments applied in 1994, but significant mating disruption did occur under both treatments. Based on measurements of residual disparlure after field aging, the flakes released 32 and 48% of their disparlure content during the 6 weeks of male moth flight in 1993 and 1994, respectively. The smaller beads used in 1993 released 75% of their disparlure content, and the larger beads used in 1994 released 52% of their disparlure content, during the 6 weeks of male flight. The biological efficacy data suggest that the bead and flake formulations, as applied in these tests, have similar effects on gypsy moth mating disruption and subsequent population growth. Based on the observed release rates from both 1993 and 1994, a single application of the beads would provide emission rates equal to or greater than those provided by the flakes when applied at an equal dose.

Enantioselective opening of (+)- and (–)- disparlure by epoxide hydrase in gypsy moth antennae

Both enantiomers of the gypsy moth sex pheromone disparlure are converted to the (7R,8R)-threo diol by epoxide hydrase(s) located in the antennae of the male gypsy moth (Lymantria dispar), as determined by capillary gas chromatography of the diol bis(trifluoroacetate) enantiomers on a chiral stationary phase.

Studies on the identification and synthesis of insect pheromone: XXIV. Synthesis of (7R, 8S)-(+)- and (7S, 8R)-(−)-sex pheromone of gypsy moth and stereochemistry of β-hydroxysilane

Condensation of the epoxy aldehyde 2 or 2 prepared by Sharpless asymmetric epoxydation in 96—97% yield, with trimethylsilane lithiated 3 gave 7 or 7′, which after transformation to the corresponding acetoxyl compound 8 or 8′ afforded the title compound 1a or 1b via β-acetoxysilane elimination and catalytic homogeneous hydrogenation. The configurations of the stereoisomers 7 and 7′ were determined.

Enzymatic resolution of 2,3-epoxyalcohols, intermediates in the synthesis of the gypsy moth sex pheromone

An efficient resolution of 2,3-epoxyalcohols 2a-b were obtained both by enzymatic hydrolysis and transesterification in organic solvent: (25,3R) 2b and (2R,35) 2a thus obtained are chiral synthons for the synthesis of (+)- Disparlure 1.

Studies on the identification and syntheses of insect pheromones: XX. Synthesis of (7R, 8S)-(+)-sex pheromone of gypsy moth through the kinetic resolution of (±) allylic alcohol by Sharpless asymmetric epoxidation

The chiral epoxy alcohol (1, 2R)-epoxy-3S-tridecanol (3) was synthesized in 92％ e. e. according to kinetic resolution of (±) 1-tridecen-3-ol (2) by Sharpless asymmetric epoxidation. 3 was then transformed to (7R, 8S)-la, the sex pheromone of gypsy moth, in overall yield of 60％ in 5 steps.

Studies on the identification and synthesis of insect pheromone: XVI. Synthesis of the optically active sex pheromone of gypsy moth and its three other optical isomers

The title compounds 1a～d were synthesized from(+)-(R)-glyceraldehyde acetonide (2) obtained from mannitol in 9～10 steps in an overall yield of 20～30%. Thus, Grignard reaction of 2 with n-C_(10)H_(21)MgBr yielded a mixture of two diastereoisomers which afforded 3(erythro form, R, S) and 4 (threo form, R, R) by SiO_2 gel chromatography. The free alcohol 3 was reacted with benzyl chloride followed by acidic hydrolysis to give diol 6 which on selective tosylation followed by treatment with 0.25 M methanolic KOH gave an epoxide 8. 8 was treated with(i-hex)_2 OuLi in ether to give 9 which on removal of the benzyl protecting group followed by reaction with HBr-HOAc gave a mixture of 11a and 11b. Finally, treatment of the mixture of 11a and 11b with 0.5M methanolic KOH gave (+)-disparlure(1a). 1c and 1d were obtained from 9 by the reaction sequences as shown in the Chinese Text. The (-)-disparlure (1b) was obtained from 4 by the reaction sequences of 5'→6'→7'→8'→9'→1b.

Regioselection in the alkylation of trimethylsilylallyl anion - stereoselective synthesis of disubstituted alkenes

The regioselection in the alkylation of trimethylsilylallyl anion can be controlled by the use of Schlosser's base to give predominately γ-product with trans-geometry at the double bond. Application of this approach to the synthesis of Z-9-tricosene and the Gypsy moth sex pheromone is demonstrated.

Comparative distribution and persistence of disparlure in woodland air after aerial application of three controlled-release formulations

Disparlure, the gypsy moth sex pheromone, was aerially applied to three plots, using a different controlled-release formulation-gelatin microcapsules, flakes of plastic laminates, or hollow fibers-in each plot. Disparlure concentrations in air were measured intermittently over a 34-day period after application. Measurements were made at four heights above ground: 0.3,2,5, and 10m. Wind speed and air temperature were measured concurrently. Disparlure was emitted from the microcapsules and fibers at very high levels for the first day or two; thereafter, all three formulations produced gradually decreasing aerial concentrations. After 32-34 days, concentrations in all plots ranged from 1.5% to 15.5% of those on the first day, although most of the pheromone remained in the formulations. Results suggest that the effective life of all three formulations for mating disruption by atmospheric permeation would be near 30 days under the test conditions, with fibers likely to have the shortest life. Concentrations varied diurnally throughout the experiment, with highest levels generally between 1400 and 2200 hr each day. Concentrations were highest at the 10-m height with microcapsules and at the 0.3- and 10-m heights with flakes, but were similar at all heights with fibers. Biological implications of the results are presented.

A new stereoselective synthesis of racemic disparlure, the sex pheromone of gypsy moth ( [formula omitted] L.)

A new stereoselective synthesis of racemic disparlure, the sex pheromone of gypsy moth ( [formula omitted] L.)

Chemicals related to the gypsy moth sex pheromone as attractants and as synergists or inhibitors of the pheromone.

Chemicals related to the gypsy moth sex pheromone as attractants and as synergists or inhibitors of the pheromone.

The synthesis of alkenes from carbonyl compounds and carbanions alpha to silicon. III. A full report and a synthesis of the sex pheromone of gypsy moth.

The synthesis of alkenes from carbonyl compounds and carbanions alpha to silicon. III. A full report and a synthesis of the sex pheromone of gypsy moth.