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

In 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.     

Ground application of mating disruption against the gypsy moth (Lepidoptera: Erebidae)

The gypsy moth, Lymantria dispar (L.) (Lepidoptera: Erebidae), is a non‐native defoliating insect that continues to expand its range in North America and undergo periodic outbreaks. In management efforts to suppress outbreaks, slow its spread and eradicate populations that arrive outside of the invaded range, aerial deployments of mating disruption tactics and pesticides are generally used. However, in some cases, such as in heavily urbanized areas or other landscapes where aerial deployments are not feasible or permitted, ground applications are required. Ground applications tend to be labour‐intensive to ensure adequate coverage. To better inform optimal deployment of ground applications of mating disruption, we measured the effectiveness of a pheromone formulation designed for ground application, SPLAT® GM, in forested areas of Virginia from 2011 to 2014 using different dosages and number of point applications. We observed that SPLAT® GM applied to the tree trunks at the dosages of 49.4 and 123.6 g AI/ha in 11 × 11 systematic grids (i.e., every 11 m) reduced male trap catch by >90% relative to untreated control plots, which based on previous studies corresponds to >95% reduction in gypsy moth mating success. Our observations suggest that ground applications of gypsy moth mating disruption can be a successful management tool when circumstances require it.     

Optimization of pheromone dosage for gypsy moth mating disruption

The effect of aerial applications of the pheromone disparlure at varying dosages on mating disruption in low‐density gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae), populations was determined in field plots in Virginia, USA during 2000 and 2002. Six dosages [0.15, 0.75, 3, 15, 37.5, and 75 g active ingredient (AI)/ha] of disparlure were tested during the 2‐year study. A strongly positive dose–response relationship was observed between pheromone dosages and mating disruption, as measured by the reduction in male moth capture in pheromone‐baited traps and mating successes of females. Dosages of pheromone 15 g AI/ha (15, 37.5, and 75 g AI/ha) reduced the mating success of females by >99% and significantly reduced male moth catches in pheromone‐baited traps compared to untreated plots. Pheromone dosages <15 g AI/ha also reduced trap catch, but to a lesser extent than dosages 15 g AI/ha. Furthermore, the effectiveness of the lower dosage treatments (0.15, 0.75, and 3 g AI/ha) declined over time, so that by the end of the study, male moth catches in traps were significantly lower in plots treated with pheromone dosages 15 g AI/ha. The dosage of 75 g AI/ha was initially replaced by a dosage of 37.5 g AI/ha in the USDA Forest Service Slow‐the‐Spread (STS) of the Gypsy Moth management program, but the program is currently making the transition to a dosage of 15 g AI/ha. These changes in applied dosages have resulted in a reduction in the cost of gypsy moth mating disruption treatments.     

A comparison of various mating disruption technologies for control of two internally feeding Lepidoptera in apples

Sex pheromone mating disruption (MD) is an approach used to control several moth pest species of pome fruit by disrupting the ability of the males to find females and consequently prevent mating. The following experiments were performed to determine the effectiveness of several new and experimental sex pheromone MD technologies, and dispenser densities for simultaneous control of the codling moth (CM), Cydia pomonella (L.), and the oriental fruit moth (OFM), Grapholita molesta (Busck) (both Lepidoptera: Tortricidae), in Pennsylvania apple orchards. In one study, three MD approaches to control CM and oriental fruit moth – CM and OFM Disrupt Micro‐Flakes, Isomate CM/OFM TT, and both a CideTrak OFM and a CideTrak CM dispenser containing both codlemone and pear ester – and an insecticides‐only treatment were compared over the course of 2 years. In the other studies, the efficacy of several CheckMate Duel dispenser densities (i.e., 250, 375, 425, and 500 dispensers ha^?1) were compared against Isomate CM/OFM TT, and an insecticides‐only treatment. The CideTrak CM/pear ester combination and Isomate CM/OFM TT treatments both substantially reduced CM captures in traps in 2007 and 2008. Meanwhile, OFM trap shutdown was highest in the CheckMate Duel densities of 375 (99.9 ± 0.08%) and 500 dispensers ha^?1 (98.9 ± 0.07%) and the Isomate CM/OFM TT treatment (98.0 ± 1.13%), and lowest in the 250 dispensers ha^?1 density treatment (94.3 ± 3.23%). In orchards where OFM is the dominant pest species, a CheckMate Duel dispenser density of 375 ha^?1 is necessary for effective control, whereas higher densities are needed to control CM.     

Potential of high‐density pheromone‐releasing microtraps for control of codling moth Cydia pomonella and obliquebanded leafroller Choristoneura rosaceana

Recent large‐cage studies with codling moth Cydia pomonella (L.) reveal that the removal of moths from an apple orchard using pheromone‐releasing traps is more effective at reducing capture in a central monitoring trap than is a mating disruption protocol without kill/capture. The present study uses open orchard 0.2‐ha plots comparing a high‐density trapping scenario with mating disruption to confirm those results. Two tortricid moth pests of tree fruit are studied: codling moth and obliquebanded leafroller Choristoneura rosaceana (Harris). Codling moth treatments include Isomate CM FLEX (ShinEtsu Ltd, Japan), nonsticky traps baited with Trécé CM lures (Trécé, Inc., Adair, Oklahoma), and sticky traps baited with Trécé CM lures, all at equal application rates of 500 dispensers ha^?1, as well as a no pheromone control. These microtraps are of a novel design, small and easy to apply, and potentially inexpensive to produce. Mating disruption using Isomate CM FLEX and nonsticky traps reduces codling moth capture in standard monitoring traps by 58% and 71%, respectively. The attract‐and‐remove treatment with sticky traps reduces capture by 92%. Obliquebanded leafroller treatments include Isomate OBLR/PLR Plus and Pherocon IIB microtraps baited with Trécé OBLR lures, both applied at 500 dispensers ha^?1, as well as a no pheromone control. Mating disruption reduces capture in monitoring traps by 69%. The attract‐and‐remove treatment reduces capture by 85%. Both studies suggest that an attract‐and‐remove approach has the potential to provide superior control of moth populations compared with that achieved by mating disruption operating by competitive attraction.     

Sprayable pheromone for controlling the North American grape berry moth by mating disruption

Abstract 1 Sex pheromone‐mediated mating disruption can be used to provide economic control of the North American grape berry moth in commercial vineyards. Controlled release devices that use a plastic tube or polymer to regulate the emission of pheromone have been registered for use in Canada for controlling this pest. These dispensers require manual application, whereas a newly developed microencapsulated formulation can be applied using a vineyard airblast sprayer. 2 The efficacy of 3M Sprayable Pheromone was compared with the efficacy of Isomate^® GBM pheromone dispensers and organophosphorus insecticide for controlling the grape berry moth during the 1997 and 1998 growing seasons. Two application schedules of sprayable pheromone were tested during 1997 and two formulations of sprayable pheromone were tested during 1998. The mating disruption efficiency of the pheromone treatments was compared using pheromone‐baited traps and the efficacy of the pheromone and insecticide treatments was compared by inspecting grape clusters for feeding injury caused by grape berry moth larvae. 3 The estimated mating disruption efficiency of the pheromone treatments ranged from 67 to 100%. There was no difference in the efficiency of the two application schedules of 3M Sprayable Pheromone during 1997. The estimated efficiency of Isomate^® GBM was greater than that of 3M Sprayable Pheromone during the first two flights of 1997. During 1998, the estimated efficiency of 3M Sprayable Pheromone and Isomate^® GBM was similar. 4 The average percentage of grape clusters with grape berry moth feeding injury was greater in the border than in the interior zone on 13 ocassions, and greater in the interior zone than in the border zone of experimental plots on six of the 72 occasions when clusters were inspected during the 2‐year study. 5 The average percentage of grape clusters with feeding injury was similar in plots treated with 3M Sprayable Pheromone, Isomate^® GBM and insecticide during both years of the study. There was no difference in feeding injury in plots treated with 3M Sprayable Pheromone and Isomate^® GBM, despite the greater estimated mating disruption efficiency of Isomate^® GBM. 6 The use of sprayable pheromone may have several operational and cost advantages compared with a hand‐applied dispensing system such as Isomate^® GBM.     

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.     

Reduced antennal sensitivity, behavioural response, and attraction of male codling moths, Cydia pomonella, to their pheromone (E,E)-8,10-dodecadien-1-ol following various pre-exposure regimes

The effects of pre‐exposing male codling moths, Cydia pomonella (L.) (Lepidoptera: Tortricidae), to their pheromone (E,E)‐8,10‐dodecadien‐1‐ol (codlemone), in static and moving air, under laboratory and field conditions, on subsequent antennal sensitivity, behavioural responsiveness, and attraction to codlemone were investigated. In flight tunnel experiments, the percentage of moths wing fanning and taking flight were mostly unaffected, but upwind flight to, and contact with, pheromone sources known to elicit responses of both were shown to depend on the intensity and duration of previous exposure to codlemone and recovery time between exposure and assessment. Ten to 30‐min pre‐exposures to codlemone in static air (≈ 35 µg l^?1) not only caused a 99% reduction in attraction, but also significantly reduced electroantennogram response to codlemone. Recovery of full antennal sensitivity to codlemone took more than 1 h, but recovery of attraction took over 4 h, suggesting that habituation is also partially involved in reduced behavioural responsiveness following pre‐exposure. Seventy‐five min exposures to codlemone in moving air (5–10 cm s^?1) at rates of 0.9, 4.5, and 18 µg h^?1 from Celcon fibres caused 75, 86, and 99% disruption, respectively. However, 30–34‐h exposure of caged moths to air moving through an orchard treated with 1000 Isomate‐C® dispensers ha^?1 releasing approximately 20 µg h^?1 per dispenser during tests, had no impact on moth response in flight‐tunnel assays 30 min after removal from the orchard. In this treated orchard, catches of free‐flying moths in pheromone‐baited traps were completely inhibited. If observed mechanisms such as long‐lasting antennal adaptation or habituation of the central nervous system contribute to the disruption of pheromone communication among codling moths under field conditions, it seems unlikely that they occur following exposure to the average atmospheric concentrations of codlemone. For these effects to be important, codling moths may require close contact with pheromone sources for extended periods, or repeated close encounters.     

Gypsy moth mating disruption in open landscapes

1 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.     

Pheromone release rate determines whether sexual communication of Oriental fruit moth is disrupted competitively vs. non‐competitively

Communicational disruption mechanisms for Oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae), were determined using a suite of mathematical tools and graphical operations that enable differentiation between competitive attraction and non‐competitive mechanisms of disruption. Research was conducted in 20 field cages, each covering 12 mature apple trees. Commercial monitoring lures releasing Oriental fruit moth pheromone at a rate of 0.04 μg h^?1 and distributed at densities of 0, 1, 2, 4, 8, and 17 per cage were used to evaluate the effect of low‐releasing dispensers on the disruption of sexual communication. Graphical analyses revealed that near‐female‐equivalent pheromone dispensers disrupted Oriental fruit moth competitively. Commercial mating disruption dispensers releasing Oriental fruit moth pheromone at 60 μg h^?1 and deployed at 0, 4, 6, 10, 15, 20, and 30 per cage were used to evaluate the effect of high‐releasing dispensers on the disruption of sexual communication. Oriental fruit moth disruption shifted to a non‐competitive mechanism for high‐releasing dispensers. This is the first time such a shift in disruption mechanism has been demonstrated against a background of otherwise identical experimental conditions. Near‐female‐equivalent pheromone dispensers were also used to quantify the additive effect of an attract‐and‐remove control strategy compared with competitive mating disruption. We report a five‐fold reduction in Oriental fruit moth captures under attract‐and‐remove compared to mating disruption using near‐female‐equivalent dispensers. Surprisingly, release of female Oriental fruit moths into these large‐cage disruption studies had no measurable impact on male trapping.     

Mating disruption of pea moth (Cydia nigricana) in organic peas (Pisum sativum)

We appraised mating disruption (MD) to control pea moth, Cydia nigricana (Fabricius) (Lepidoptera: Tortricidae), by assessing male attraction to monitor traps, larval pod infestation, and larval age structure in pheromone‐treated and untreated grain pea fields [Pisum sativum L. (Fabaceae)], over a 5‐year period. Cellulose pheromone dispensers were manually attached to the top shoots of pea plants and released 540 mg ha^?1 day^?1 synthetic pheromone E8,E10‐dodecadien‐1‐yl acetate in a first test series (2000–2001) and ca. 4 200 mg pheromone ha^?1 day^?1 in a second series (2004–2006). The dispensers had a half‐life of about 30 days. Although male attraction to pheromone monitoring traps was largely suppressed at the edges and within MD fields in both test series, MD treatments did not reduce pod infestation in the open field in 2000 and 2001. In the 2004–2006 series, larval damage reduction was achieved in the majority of the trials but overall MD efficacy in the open field was only 61% and not significant. In contrast, in field cages placed within the experimental sites and supplied with unmated pea moths, MD control was consistently high and significant. There were no obvious differences in the larval age distribution in all MD and control treatments, suggesting that infestations started and developed further similarly. As a univoltine species, C. nigricana larvae stay in the soil of pea fields for hibernation and pupate. The following year, emerging adults disperse and fly to the closest pea crop. Combined emergence site and pea crop treatments were conducted over 2 years to include this early migration phase of C. nigricana adults. However, the emergence site treatments did not enhance MD‐control efficacy. We conclude that mating activity was only prevented in cage tests, whereas substantial mating occurred during the transit phase outside the pheromone‐treated fields either within non‐crop vegetation and/or at the edges of pheromone‐treated pea fields orientated upwind. Thus, resulting gravid female entry can be regarded as the major constraint to reliable MD control.     

Dosage-mortality studies with commercial Bacillus thuringiensis sprayed in a modified Potter's tower against some forest insects

Dosage-mortality tests were carried out with commercial Bacillus thuringiensis (B.T.) (Dipel)^® against various instars of the spruce budworm, Choristoneura fumiferana, the white-marked and Douglas fir tussock moths, Hemerocampa leucostigmata and Orgyia pseudotsugata, and the gypsy moth, Porthetria dispar. Dipel was applied as a dilute (10^?2) molasses suspension onto artificial diet surface in a spray tower designed to simulate aerial application. Probit analysis of the results showed that LD₅₀s expressed both in terms of gallons deposited per acre and as spores and crystals deposited per cm² increased with larval age for all species. The spruce budworm was the most sensitive to the bacteria, followed in decreasing order of sensitivity by the white-marked tussock moth, Douglas fir tussock moth, and the gypsy moth. The mean slopes for all instars of the four species were 1.6, 3.1, 2.6, and 2.2, respectively, indicating that precision-wise, the assay of B.T. on artificial medium was good. The relatively low slope for spruce budworm is explained by its peculiar feeding habit. Among all species tested, bacteria-treated larvae gained weight at a considerably reduced rate compared with untreated ones. Reduction in weight resulting from lowered feeding activity intensified as dosage rates increased. The implication of this in terms of mortality assessments in microbial control operations is discussed.It is suggested that 0.02 gallon (4 × 10⁶ International Units) of Dipel Molasses deposited per acre may achieve economic control of fourth- to sixth-instar budworm and first-to second-instar gypsy moths. A deposit rate for second- to fifth-instar white-marked or Douglas fir tussock moths appears to be in the vicinity of 0.01 gallon (2 × 10⁶ IU) per acre.     

Forest edges enhance mate‐finding in the invasive European gypsy moth,Lymantria dispar

Habitat type, fragmentation, and edge effects can play important roles in the mate‐finding abilities of many species. These effects can be particularly pronounced in low‐density populations, which are often found at the margins of species' ranges or at the leading edge of an invasion. The European gypsy moth, Lymantria dispar (L.) (Lepidoptera: Erebidae), is a non‐native insect defoliator in the USA and Canada, where flightless females attract male moths through pheromone production and local extirpation of low‐density populations can be due to mate‐finding failure. To assess the effects of habitat edges on the ability of gypsy moths to find mates, we conducted a release experiment with male gypsy moths using female‐baited trap arrays in fields, at forest edges, and in the forest interior. Reduced mate‐finding was expected in fields and near forest edges based on geographic variation in invasion rates, male flight behavior, and pheromone plume dynamics. However, we found that mate‐finding was highest at forest edges, reduced in fields, and lowest within the forest interior. Within an array, traps closest to the forest edge also had the highest mate‐finding, suggesting that habitat characteristics can influence male flight direction in addition to pheromone cues. These results suggest that a moderate level of forest fragmentation enhances mate‐finding ability in the gypsy moth. Understanding the relationship between habitat heterogeneity and mate‐finding success in invasive species can inform predictions of future spread and assist with management plans that target mating disruption.     

Attractiveness of year-old polyethylene Isonet sex pheromone dispensers for Lobesia botrana

In this study, we have compared the release of sex pheromone from mating disruption dispensers exposed in the field for 12 months and from calling females. The main pheromone component of the grapevine moth, Lobesia botrana (D. and S.) (Lepidoptera: Tortricidae), is (E)‐7,(Z)‐9‐dodecadienyl acetate, and a minor component is (Z)‐9‐dodecenyl acetate. Aged dispensers from two different years emitted a much higher amount of both pheromone components than calling females. However, the summer temperature during field exposure influenced the release from mating disruption dispensers the following year. In the wind tunnel, male L. botrana were equally attracted to 12‐month, field‐exposed dispensers, a standard monitoring pheromone lure, and to synthetic (E)‐7,(Z)‐9‐dodecadienyl acetate sprayed at the rate of 0.6–60 ng h^?1. Field trapping tests confirmed that aged dispensers from both years were at least as attractive to L. botrana males as a standard monitoring pheromone lure. The possible contribution of previously applied dispensers to the mating disruption efficacy during following applications is discussed.     

Management of diamondback moth,Plutella xylostella (Lepidoptera: Plutellidae) by mating disruption

Abstract Field trials were conducted in China in 2008 and 2009 to evaluate the efficacy of mating disruption (MD) on diamondback moth, Plutella xylostella, in cabbage, Brassica oleracea var. capitata. Effectiveness was positively correlated with the MD dispenser density in the field. A density of 167 MD dispensers per ha produced an average population decrease of about 50% compared to the conventional‐practice field. Significant fewer males were captured in pheromone‐treated and conventional‐practice fields than in the blank control field, but the difference was not significant between the pheromone‐treated and conventional‐practice fields. In addition, fewer eggs and larvae were observed in pheromone‐treated fields. Our results suggest mating disruption coupled with minimal insecticidal supplements is a promising solution for resistance management and control of diamondback moth infestation.     

Pheromone-mediated communication disruption in Guatemalan potato moth, Tecia solanivora

Chemical analysis of pheromone gland extracts followed by behavioural studies in the wind tunnel and by field trapping tests show that the sex pheromone of the Guatemalan potato moth, Tecia (Scrobipalpopsis) solanivora Povolny (Lepidoptera: Gelechiidae), is a blend of (E)‐3‐dodecenyl acetate, (Z)‐3‐dodecenyl acetate, and dodecyl acetate. A 100 : 1 : 20 blend of these compounds, formulated at 1000 µg on rubber septa, captured more males than the main compound alone. This lure was species‐specific and did not capture the potato tubermoth, Phthorimaea operculella. A potato field was treated with a blend of these three compounds at a rate of 28 g ha^?1. Male T. solanivora attraction to synthetic pheromone traps was almost completely suppressed for 2 months, demonstrating the potential use of pheromones for control of this economically important insect pest of potato in Central and Southern America.     

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

The 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.     

Calibration of an EAG system to measure airborne concentration of pheromone formulated for mating disruption of the pink bollworm moth, Pectinophora gossypiella (Saunders) (Lep., Gelechiidae)

Abstract: Electroantennogram (EAG) devices, used to measure airborne pheromone density in mating disruption experiments, so far have provided only ‘relative units’ of concentration rather than absolute concentration values. This paper describes a technique to measure the amount of pheromone delivered by calibration syringes into the Kaiserslautern EAG pheromone measurement device, thereby allowing such relative units of concentration to be converted into absolute concentrations. The synthetic pheromone used in these calibrations is of Pectinophora gossypiella (Saunders), the pink bollworm moth, and consists of a 1 : 1 mix of (Z,Z)‐ and (Z,E)‐7,11‐hexadecadienyl acetates. The syringe, driven as in field use, delivers its pheromone–air mixture into a glass capillary where it is adsorbed. The amount of pheromone trapped is measured by gas chromatography. The results show a linear relationship between the ratio of pheromone : silicone oil in a syringe and the pheromone concentration in the air puffs it generates. Efficacious mating disruption of P. gossypiella in cotton occurs with 10^?6 relative EAG units, which corresponds to an aerial pheromone density of 1.7 ± 0.15 ng/m³.     

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

The 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.     

Pheromone‐trapping the nun moth,Lymantria monacha (Lepidoptera: Lymantriidae) in Inner Mongolia,China

The nun moth, Lymantria monacha L., is one of the most important defoliators of Eurasian coniferous forests. Outbreaks during 2011–2015 in the natural/planted larch, and larch‐birch mixed forests of the Greater Khingan Range in Inner Mongolia, China, caused tremendous timber losses from severe defoliation and tree mortality. A series of trapping experiments were conducted in these outbreak areas to evaluate the efficacy of a synthetic species‐specific pheromone lure based on the female pheromone blend of European nun moth populations. Our results clearly show that the nun moth in Inner Mongolia is highly and specifically attracted to this synthetic pheromone, with few gypsy moths (Lymantria dispar) captured. Flight activity monitoring of L. monacha male moths using pheromone‐baited Unitraps at 2 locations during the summer of 2015 indicated that the flight period started in mid‐July, peaking in early August at both locations. Based on male moth captures, there was a strong diurnal rhythm of flight activity throughout the entire scotophase, peaking between 22:00 and 24:00. Unitraps and wing traps had significantly and surprisingly higher catches than the gypsy moth traps. Unitraps fastened to tree trunks 2 m above ground caught significantly more male moths than those at the ground level or at 5 m height. Male L. monacha moths can be attracted to pheromone‐baited traps in open areas 150–200 m distant from the infested forest edge. Our data should allow improvement on the performance of pheromone‐baited traps for monitoring or mass‐trapping to combat outbreaks of this pest in northeastern China.