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.     

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

Several 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.     

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.     

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.     

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.     

Comparison of mating disruption with pesticides for management of oriental fruit moth (Lepidoptera: Tortricidae) in North Carolina apple orchards

The efficacy of mating disruption by using Isomate-M 100 pheromone dispensers and two formulations of microencapsulated sprayable pheromone for management of oriental fruit moth, Grapholita molesta (Busck), was compared with conventional insecticides in large plot studies in Henderson County, North Carolina, in 2000 and 2001. In addition, experiments were conducted in small and large plots to test the response of oriental fruit moth males to different application rates of sprayable pheromone. Pheromone trap catches were significantly reduced in mating disruption blocks compared with conventional and abandoned orchards. Pheromone traps placed in the upper canopy captured significantly more moths than traps placed in the lower canopy across all treatments, and lures loaded with 100 microg of pheromone caught more moths than traps with 300 microg, but the difference between doses was statistically significant at only one location in 2001. Isomate-M 100 provided excellent trap shutdown and was significantly more effective than sprayable pheromone formulations. Fruit damage by oriental fruit moth larvae was very low (< or = 1%) in mating disruption blocks and was generally lower than in conventional and nonmanaged blocks. Based on male moth response to pheromone traps in small plots, there was little difference among doses of sprayable pheromone, ranging from 12.4 to 49.1 g (AI)/ha, but efficacy declined at 2.4 g (AI)/ha. With the exception of one orchard, there was no significant difference between 12.4 and 37.1 g (AI)/ha under low and high oriental fruit moth population pressure in large plot studies. Mating disruption proved to be an alternative to organophosphate insecticides for managing oriental fruit moth populations in North Carolina apple orchards.     

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.     

Combined approaches using sex pheromone and pear ester for behavioural disruption of codling moth (Lepidoptera: Tortricidae)

Attractive properties of pear ester, ethyl (E,Z)‐2,4‐decadienoate, and codlemone, (E,E)‐8,10‐dodecadien‐1‐ol, the sex pheromone of codling moth, Cydia pomonella (L.), were utilized in experiments on behavioural disruption of mating. Standard dispensers loaded with codlemone alone or in combination with pear ester (combo) were applied at 500–1000/ha. Larger (10‐fold) combo dispensers (Meso) were evaluated at a rate of 80/ha. The addition of microencapsulated pear ester, PE‐MEC, sprayed with insecticides at 30 ml/ha was also evaluated. Male moth catches in unmated female‐baited traps were lower in standard combo dispenser than in codlemone dispenser–treated plots. Female moth catch in traps baited with the combination of pear ester, codlemone and acetic acid was lower in standard combo dispenser than in codlemone dispenser–treated plots. In 12 comparative experiments spanning from 2006 to 2012, male moth catch in unmated female‐baited traps was consistently and significantly lower in combo than in codlemone dispenser–treated plots. Male catch in codlemone‐baited traps did not differ between dispenser treatments in eight studies from 2006 to 2009. These results emphasize the benefit of alternatively using traps baited with unmated females over codlemone lures for the analysis of dispenser activity. Fruit injury was significantly reduced with the addition of PE‐MEC to insecticide applications across untreated and dispenser treatments. Proportion of unmated females trapped was higher in standard combo dispenser than in codlemone dispenser–treated and untreated plots. Similarly, the proportion of unmated females caught was higher in the Meso combo dispenser than in nearby or distant codlemone dispenser–treated plots. These field studies conducted in apple over 3 years demonstrate that adding pear ester both to pheromone dispensers, either standard or Meso, and to supplementary insecticide sprays can provide a significant increase in the disruption of sexual communication, reductions in female mating and reductions in fruit injury.     

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.     

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.     

Field evaluation of effect of temperature on release of disparlure from a pheromone-baited trapping system used to monitor gypsy moth (Lepidoptera: Lymantriidae)

Traps baited with disparlure, the synthetic form of the gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae), sex pheromone are used to detect newly founded populations and estimate population density across the United States. The lures used in trapping devices are exposed to field conditions with varying climates, which can affect the rate of disparlure release. We evaluated the release rate of disparlure from delta traps baited with disparlure string dispenser from 1 to 3 yr across a broad geographic gradient, from northern Minnesota to southern North Carolina. Traps were deployed over approximately 12 wk that coincided with the period of male moth flight and the deployment schedule of traps under gypsy moth management programs. We measured a uniform rate of release across all locations when considered over the accumulation of degree-days; however, due to differences in degree-day accumulation across locations, there were significant differences in release rates over time among locations. The initial lure load seemed to be sufficient regardless of climate, although rapid release of the pheromone in warmer climates could affect trap efficacy in late season. Daily rates of release in colder climates, such as Minnesota and northern Wisconsin, may not be optimal in detection efforts. This work highlights the importance of local temperatures when deploying pheromone-baited traps for monitoring a species across a large and climatically diverse landscape.     

Sprayable microencapsulated sex pheromone formulation for mating disruption of oriental fruit moth (Lepidoptera: Tortricidae) in Australian peach and pear orchards

Areawide mating disruption treatments have been effective in controlling infestation of oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae), in Australian pome and stone fruit orchards. Although successful, the areawide mating disruption program has been an expensive approach by using hand-applied Isomate dispensers. Sprayable microencapsulated (MEC) pheromone formulations that can be applied with standard spray equipment could substantially reduce the cost of application. Field trials conducted during two consecutive seasons (2002-2004) demonstrated that monthly applications of MEC-OFM phase V (3M Canada, London, Ontario, Canada) at a rate of 125 ml/ha (37.1 g [AI]/ha) in replicated 2-ha blocks of both peaches and pears reduced oriental fruit moth shoot tip and fruit damage as effectively as a single application of Isomate OFM Rosso hand-applied dispensers (500 dispensers per ha) and as or more effectively than standard broad-spectrum insecticide sprays. Fruit protection was achieved despite high oriental fruit moth population densities in both crops as measured by moth catches in terpinyl acetate food and pheromone traps. Similar numbers of oriental fruit moths were captured among all treatments in food traps but captures of males in pheromone traps were disrupted (96-99%) in pheromone-treated blocks relative to controls. The results of this study suggest that microencapsulated formulations of pheromone could be effectively used in areawide mating disruption programs for oriental fruit moth in Australia as a cost-saving alternative to reservoir-style dispensers requiring labor-intensive hand application.     

Factors influencing the effectiveness of an attracticide formulation against the Oriental fruit moth, Grapholita molesta

An attracticide formulation, LastCall?OFM, was tested against the Oriental fruit moth Grapholita molesta (Busck) (Lepidoptera: Tortricidae) in replicated small plot field trials in apple, Malus domestica (Borkhausen), orchards in South‐eastern Pennsylvania, USA. Attracticide treatments were applied using a calibrated hand pump, and treated plots were compared to similar untreated plots. Male moth activity was monitored using virgin female‐baited traps, and the potential for reduction in mating activity was assessed using sentinel virgin females. A comparison of application rates showed that 1500 droplets per ha of the attracticide formulation was as effective as 3000 droplets per ha, and both application rates reduced captures in synthetic pheromone‐baited traps for prolonged periods. Droplets placed either at high or low positions within the canopy significantly reduced trap capture and mating with sentinel females. In addition, the only sentinel females that mated in the treated plots were located in the untreated portion of the tree canopy. Mate finding behaviour was equally disrupted by formulations with and without insecticide. Therefore, under the test conditions, the mechanism by which the attracticide formulation worked was by disruption of male orientation, and not by the removal of males due to insecticide poisoning. Two field cage experiments tested the impact of population density on the competitiveness of the attracticide formulation compared to virgin females. A significant proportion of males were captured in female‐baited traps at the highest female‐to‐droplet ratio tested. Equal proportions of males were captured in attracticide‐baited traps at male moth densities of 10, 20, 40, and 80 males per cage. These results clarify some of the factors influencing the effectiveness and possible mechanisms of an attracticide management tactic against the Oriental fruit moth.     

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.     

Monitoring codling moth (Lepidoptera: Tortricidae) with a four‐component volatile blend compared to a sex pheromone‐based blend

Monitoring adult codling moth, Cydia pomonella (L.), is a crucial component in implementing effective integrated management programmes in apple, Malus domestica Borkhausen. Use of sex pheromone lures to track male populations has been the traditional approach, but their use in orchards treated with sex pheromone for mating disruption (MD) has been problematic. Development of kairomone and kairomone–pheromone combination lures has allowed the catch of female moths and has benefited several aspects of codling moth management through improved spray timings and action thresholds. Recently, a new four‐component volatile blend (4‐K) comprised of pear ester, (E,Z)‐2,4‐ethyl decadienoate (PE), (E)‐11 4,8‐dimethyl‐1,3,7‐nonatriene, all isomers of pyranoid linalool oxide and acetic acid (AA) has been characterized that has increased female moth catch threefold versus any previous blend. Field trapping studies were conducted to compare moth catches in traps baited with 4‐K versus the use of sex pheromone, (E,E)‐8,10‐dodecadien‐1‐ol (PH) in combination with PE and AA. Trials were conducted in orchards left either untreated, or treated with PH or PH + PE. Traps baited with 4‐K and 4‐K + PH lures caught significantly more females than traps baited with PH + PE + AA lures. Traps baited with 4‐K + PH lures caught significantly more total moths than traps baited with PH + PE + AA lures in all three orchards. Adding a PH lure to traps with the 4‐K lure did not affect female catch, but significantly increased male and total moth catches. These studies demonstrate that codling moth can be trapped effectively in apple under MD without the use of sex pheromone lures. The significant increase in female codling moth catch with the 4‐K lure suggests that efforts to improve spray timings and action threshold determinations as well as mass trapping might be enhanced with this new lure.     

Effectiveness of gypsy moth mating disruption from aerial applications of plastic laminate flakes with and without a sticking agent

1 The plastic laminate flake formulation, Disparlure II, is currently the only gypsy moth mating disruption product available for aerial application. The elimination of a sticking agent from the formulation would reduce costs, simplify application, and make it possible to apply the product without specialized equipment. 2 A test was conducted in wooded plots in Virginia during 1997 and 1998 to determine whether a sticking agent is necessary. Treatment effectiveness was assessed from the rates of male moth capture in pheromone‐baited traps and mating success of both laboratory‐reared and wild females. 3 Male moth capture was reduced 75.6 and 92.9% in plots treated with flakes without and with a sticking agent, respectively. The percentage of mated females that produced egg masses with more than 5% fertile eggs was reduced by 86.3 and 99.5% in plots treated with flakes without and with a sticking agent, respectively. 4 Moth capture and mating success of laboratory‐reared females did not differ significantly between plots treated with flakes with and without a sticking agent. However, the consistently greater reduction in mating success in both years provides strong evidence that mating disruption is less effective when flakes are applied without a sticking agent. The proportion of wild egg masses collected in 1998 with more than 5% fertile eggs was significantly higher under the no‐sticking agent treatment. 5 In special situations where the use of a sticking agent may be problematic, such as in residential areas, the data indicate that a high level of mating disruption is likely to occur even without the use of a sticking agent.     

Development of pheromone-based mating disruption for control of the eye-spotted bud moth, Spilonota ocellana

The potential for pheromone-based mating disruption of eye-spotted bud moth (ESBM), Spilonota ocellana (Denis & Schiffermüller) (Lepidoptera: Tortricidae), in apple orchards in the Okanagan Valley of British Columbia was examined in small-plot trials. In a preliminary experiment, treatment of the orchard atmosphere with a 99:1 blend of Z8-tetradecenyl acetate (Z8-14:OAc) and Z8-tetradecenyl alcohol (Z8-14:OH) completely inhibited captures of male ESBM in pheromone-baited traps, but treatment with Z8-14:OAc alone did not. Therefore, all subsequent trials used the two-component blend as a disruptant. Mean catches of male ESBM in traps baited with 0.1, 1, 10, or 20 mg of 99:1 Z8-14:OAc and Z8-14:OH were significantly reduced (81–97%) in pheromone-treated plots relative to similar traps placed in control plots. In both control and treated plots, there was a significant positive relationship between trap bait dose and trap catch. In pheromone-treated plots, this suggests that high doses of trap baits over-ride the camouflage effect of disruption or overcome the effect of sensory adaptation and habituation. The number of virgin-female baited traps capturing at least one male ESBM was reduced by 96%, and mating of virgin females on mating tables was reduced by 95% in plots treated with the two-component pheromone. The total amount of Z8-14:OAc released from pheromone disruption dispensers during the latter field trials was estimated to average 6.4 g ha^-1 over 11 days or 26.4 mg ha^-1 h^-1. The low levels of Z8-14:OH released from disruption dispensers could not be estimated by GC analysis. Dispensers loaded with a 99:1 blend of Z8-14:OAc and Z8-14:OH were highly attractive to males in baited traps, indicating that they have the potential to induce false trail following.     

Potential for mating disruption of Sparganothis sulfureana (Lepidoptera: Tortricidae) in cranberries.

The feasibility of disrupting mating of Sparganothis fruitworm with a sprayable microencapsulated formulation of (E)-11-tetradecenyl acetate (E11-14:Ac), the major pheromone component, was evaluated in New Jersey during 1996 and 1997 seasons. In both years, application of encapsulated E11-14:Ac, at 25-187.5 g (AI)/ha, reduced the incidence of mating of virgin females placed in treated plots relative to those placed in control plots. Pheromone trap catches were lower in pheromone treated plots, indicating that fewer male moths were able to locate the traps in treated plots. Larval density and fruit damage were significantly lower in plots treated with 62.5,125, or 187.5 g (AI)/ha of pheromone than in the untreated control. Air and foliage samples were collected to determine the air titers and foliage residuals of E11-14:Ac throughout the adult flight during 1996 and 1997. E11-14:Ac levels in air and foliage samples, declined sharply one wk after the pheromone application. However, detectable levels of E11-14:Ac were present in both air and foliage samples throughout the 3- to 4-wk period after the pheromone application. Multiple applications of pheromone at lower rates may be more effective in maintaining pheromone levels than a single dose at higher rates. These results suggest that mating disruption is a promising strategy to manage Sparganothis fruitworm in cranberries.     

Electroantennogram measurements of atmospheric pheromone concentration after aerial and ground application of gypsy moth mating disruptants

Abstract:  A portable electroantennogram (EAG) sensor was used to measure relative atmospheric pheromone concentration in forest plots treated with aerial and ground applications of gypsy moth, Lymantria dispar (L.) (Lep., Lymantriidae), mating-disruption formulations. Five treatments (Disrupt II flakes with sticker, Disrupt II flakes without sticker, Disrupt II flakes in a sticker slurry, microcapsules and hand-applied Luretape), all applied at 75 g active ingredient per hectare and an untreated control were evaluated. Gypsy moth male catch in pheromone-baited traps and fertilization of deployed females were suppressed in all treatments, and no females deployed in treated plots produced more than 5% fertile eggs. Relative pheromone concentrations were significantly higher in the two treatments in which flakes were aerially applied with sticker and in the microcapsule treatment. Pheromone concentration measurements in the flakes without sticker and hand-applied treatments were not significantly different from those in the control. Mating success was negatively correlated with relative pheromone concentration. The ability of the EAG to detect differences in pheromone concentration that are correlated with mating success suggests that this could be a useful method for predicting the effectiveness of mating-disruption treatments.     

Potential for mating disruption to reduce cone damage by the spruce seed moth, Cydia strobilella, in spruce seed orchards

Abstract:  The spruce seed moth, Cydia strobilella (L.), is a serious and widely distributed pest of spruce seed orchards in North America and Europe. Current pest management activities in seed orchards rely mainly on chemical pesticides for insect control. Mating disruption with sex pheromone is a potential alternative pest management tool for C. strobilella . In 2002, field tests confirmed that sticky traps baited with 3  μ g of (E) -8-dodencenyl acetate ( E 8-12:Ac), the sex pheromone of C. strobilella , could capture males in Quebec, a region of Canada not previously monitored for this insect. In the following years (2003–2005), grey rubber septa loaded with 0.75, 1.5, or 2.0 mg of E 8-12:Ac were deployed separately in two white spruce seed orchards at a density of 40 and 60 dispensers/ha to test the potential for mating disruption. The results showed that the captures of male C. strobilella in the pheromone-treated plots were reduced by up to 98%. Furthermore, at the end of the experiment in 2005, 17.3% of cones were damaged by C. strobilella in the treated plot, compared with a significantly (P < 0.0001) higher 56.4% in the control plot. The results suggest that mating disruption has potential for controlling C. strobilella to protect seed cones in white spruce seed orchards.