Efficacy and mode of action of female‐equivalent dispensers of pheromone for mating disruption of codling moth

1 We evaluated the efficacy and mode of action of commercially available female‐equivalent dispensers of pheromone for mating disruption of codling moth Cydia pomonella (L.) (Lepidoptera Tortricidae). 2 Scentry fibres, but not Hercon flakes, were consistently as or more effective than Isomate C Plus dispensers when applied by hand at 50 dispensers per tree. 3 Individual Scentry fibres were slightly more attractive to male codling moth than Hercon flakes. 4 Efficacy of aerially applied Scentry fibres was equivalent to that of Isomate dispensers in disrupting male codling moth in 4‐ha commercial apple plots. 5 Initial deposition and retention of aerially applied fibres were inefficient with approximately 44% formulation loss at application, poor rainfastness and a gradual loss of dispensers from tree canopies after application. 6 Male codling moths were captured in traps baited with lures containing 0.1 mg of pheromone and mated with tethered virgin females that were surrounded by eight fibres placed 30 cm away or 16 fibres placed 45 cm away in untreated plots and plots treated with a background of 50 Isomate dispensers per hectare. 7 A plausible explanation for mating disruption of codling moth by female‐equivalent dispensers is competitive attraction without associated habituation and thus improving the effectiveness of these technologies will depend on maximizing the attractiveness of individual dispensers as well as the application density of dispensers per area of crop.     

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.     

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.     

Vertical distribution of codling moth adults in pheromone-treated and untreated plots

The vertical distribution of codling moth,Cydia pomonella (L.) within pheromone-treated and untreated apple and pear orchard canopies was determined using tethered virgin females, unbaited sticky traps, and blacklight observation of released moths. Mating of virgin females tethered at various heights in untreated orchard canopies increased with placement height from 1–4 m. Application of pheromone dispensers for mating disruption at 2 and 4 m above the ground greatly decreased mating. Greatest capture of males and females on unbaited sticky traps occurred at mid- and upper-canopy heights. Total capture of males and females in pheromone-treated plots was not statistically different than in untreated plots. The percentage of mated females captured on sticky traps did not vary with trap height or pheromone treatment. Released moths marked with flourescent powder and observed at dark with a blacklight indicated that moths are primarily distributed high in the canopy. However, males shifted to a position lower in the canopy when pheromone dispensers were placed 2.1 m above the ground. Results suggest that pheromone dispensers be placed in the upper canopy for optimal disruption of codling moth mating.     

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.     

Development of 2‐phenylethanol plus acetic acid lures to monitor obliquebanded leafroller (Lepidoptera: Tortricidae) under mating disruption

We evaluated the effectiveness of 2‐phenylethanol (PET) in combination with acetic acid (AA) as a binary lure for monitoring male and female obliquebanded leafroller, Choristoneura rosaceana (Harris). Studies were conducted in apple, Malus domestica Borkhausen, orchards treated with or without sex pheromone dispensers for mating disruption (MD). Open polypropylene vials, closed membrane cups, and rubber septa loaded with AA and/or PET in varying amounts were first evaluated in a series of trapping experiments. Membrane cups loaded with 800 mg of PET were as effective as 10‐mg septa, but longer lasting, and were comparable to the open vials. A membrane cup AA lure was effective in tests, but further work is needed to increase its release rate and extend its activity. Catches of codling moth, Cydia pomonella (L.), and C. rosaceana were unaffected by combining PET with (E,E)‐8,10‐dodecadien‐1‐ol, the sex pheromone of codling moth, pear ester, (E,Z)‐2,4‐ethyl‐decadienoate and AA lures. Adding (E)‐4,8‐dimethyl‐1,3,7‐nonatriene to this blend to enhance codling moth catch significantly reduced catches of C. rosaceana. PET + AA was a more attractive binary lure than AA plus phenylacetonitrile (PAN) for C. rosaceana. The addition of PET or PAN to traps already baited with the sex pheromone of C. rosaceana significantly reduced male catches. Traps baited with PET + AA placed in blocks not treated with MD caught significantly fewer C. rosaceana than traps baited with sex pheromone. In comparison, sex pheromone‐baited traps in MD blocks caught ≤1 male moth per season which was significantly lower than total moth (>10) or female moth (≥3) catch in these blocks with PET + AA. A high proportion (>70%) of trapped females were mated in both untreated and MD‐treated orchards. Further refinement of this binary, bisexual lure using membrane cup technology may allow the establishment of action thresholds and improve management timings for C. rosaceana.     

Dual pheromone dispenser for combined control of codling moth Cydia pomonella L. and oriental fruit moth Grapholita molesta (Busck) (Lep., Tortricidae) in pears

Codling moth (CM) and oriental fruit moth (OFM) are very important orchard pests worldwide, and particularly in Victoria, Australia, where both species damage pome fruit. Individually CM and OFM have been controlled successfully by pheromone‐mediated mating disruption, but treatment of pome fruit with full registered rates of two individual hand‐applied dispensers for CM and OFM could be uneconomical for growers. Field trials conducted over three seasons in plots sprayed with insecticides consistently demonstrated that dual Isomate C/OFM TT dispensers, designed to disrupt both CM and OFM, were as effective as Isomate CTT and Isomate OFM Rosso dispensers applied individually in pears for control of CM and OFM respectively. The dual‐ and individual‐species dispensers reduced moth catches and fruit damage to a similar degree. The results suggest that combined control of CM and OFM in pears by applying dual Isomate C/OFM TT dispensers at the full‐recommended rate of 500 dispensers per hectare will be more economical than use of individual species dispensers, because the price and application cost of dual dispenser is about half that for individual dispensers.     

Higher densities of distributed pheromone sources provide disruption of codling moth (Lepidoptera: Tortricidae) superior to that of lower densities of clumped sources

Field experiments quantified the effect of synthetic pheromone release-site density and distribution on 1) orientational disruption of male codling moths, Cydia pomonella (L.) (Lepidoptera: Tortricidae), to pheromone-baited traps; and 2) fruit injury. A clustering test varied pheromone release-site density from 0 to 1,000 Isomate-C Plus dispensers per ha while maintaining the total number of dispensers at 1,000. Percentage of orientational disruption of pheromone-baited traps increased significantly as a function of increasing density of release sites. Fruit injury decreased as the density of release sites increased and was lowest in plots treated with Isomate-C Plus dispensers distributed as 1,000 point sources per ha. We also manipulated point source density of 0.1-ml paraffin-wax drops containing 5% codlemone [(E,E)-8,10-dodecadien-1-ol], and thus the total amount of pheromone deployed per hectare. The percentage of disruption of traps baited with either 1.0- or 0.1-mg codlemone lures increased with increasing density of wax drops deployed. Both trapping and field observations confirmed that wax drops were attractive to male codling moths, suggesting that disruption was mediated by competitive attraction. Development of dispensers that can be mechanically applied at high densities has potential to improve the efficacy and economics of codling moth disruption at high population densities.     

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.     

Sex pheromone traps for monitoring the codling moth: effect of dispenser type, field aging of dispenser, pheromone dose and type of trap on male captures

The effects of dispenser type, dispenser aging in the field, pheromone dose in the dispenser and trap type on trapping efficiency of codling moth,Cydia pomonella (L.), males were investigated in Israel. An Israeli-manufactured rubber septum was significantly better than the CM Pherocon cap in attracting males to a Pherocon 1C cap trap or an IPS trap. The effect of aging of the dispenser in the field on trapping efficiency was significant in CM Pherocon caps and the Israeli septa. Captures in traps were negatively correlated with aging of septa. The effect of aging of dispensers was more marked during summer than during spring. The fairly rapid loss of attractancy indicates that the lures should be replaced after 2 weeks at the most. The release rate of the pheromone from the dispensers was measured in a flow system. The emission from the Israeli septa and Pherocon caps decreased sharply after 2 weeks and then was almost constant, which explains the lower attractancy of aged septa. However, there was a marked difference in the release profiles of the pheromone from the two types of dispensers, which may explain the different performance of the two dispensers. Within the range of 0.1 to 100 μg pheromone per dispenser, male response increased positively with the pheromone dose. Pheromone loadings of 100 or 1000 μg per dispenser did not differ significantly in their attractiveness for males. A load of 5000 μg per dispenser was significantly less attractive to males than was 100 or 1000 μg per dispenser. The non-sticky IPS trap was significantly better in capturing codling moth males than was the sticky, commonly used Pherocon 1C trap, provided it was baited with the Israeli dispenser. The two traps were equally effective when baited with the CM Pherocon caps. The possibility of using the non-sticky, nonsaturating and easy-to-handle IPS traps for monitoring codling moth is of great importance. Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan 50-250, Israel. No 3702-E, 1992 series.     

Large‐scale mating disruption of Ephestia spp. and Plodia interpunctella in Czech Republic,Greece and Italy

Field trials were carried out to evaluate the use of the pheromone (9Z,12E)‐tetradecadienyl acetate (TDA/ZETA) for mating disruption (MD) of Pyralidae moths associated with stored products, in most cases the Raisin moth, Ephestia cautella (Walker), Mediterranean flour moth, Ephestia kuehniella Zeller and Indianmeal moth, Plodia interpunctella (Hübner). The experiments were conducted in the Czech Republic, Greece and Italy during 2007 and 2008 in storage facilities that varied in their size and type, and included flour mills, retail stores, storage rooms with currants and raw grain stores. After a summer pre‐treatment monitoring period to assess moth population in, dispensers containing TDA were placed in the fall. Adjacent facilities without dispensers were used as control units. Pheromone‐baited traps were used to monitor the population fluctuation of the pyralid moths during the entire experimental periods. The presence of MD dispensers notably reduced the number of adults found in the traps in comparison with control rooms. Monitoring of female oviposition, measured as number of hatched larvae in cups containing food, indicated that there was a reduction in the number of larvae in the areas with MD dispensers. The results of the present work indicate that the use of mating disruption is feasible against pyralid moths in storage facilities, and should be further evaluated as a component of an integrated pest management based control strategy.     

Evaluating dispensers loaded with codlemone and pear ester for disruption of codling moth (Lepidoptera: Tortricidae)

Polyvinyl chloride polymer (PVC) dispensers loaded with ethyl (E,Z)-2,4-decadienoate (pear ester) plus the sex pheromone, (E,E)-8,10-dodecadien-1-ol (codlemone) of codling moth, Cydia pomonella (L.), were compared with PVC dispensers and a commercial dispenser (Isomate-C Plus) loaded with codlemone. Evaluations were conducted in replicated plots (0.1-0.2 ha) in apple, Malus domestica (Borkhausen) during both generations of codling moth from 2007 to 2009. Dispensers were applied at 1,000 ha(-1). Male captures in traps baited with virgin female moths and codlemone lures were recorded. Residual analysis of field-aged dispensers over both moth generations was conducted. Dispensers exhibited linear declines in release rates of both attractants, and pear ester was released at a significantly higher rate than codlemone during both time periods. The proportion of virgin female-baited traps catching males was significantly lower with combo dispenser TRE24 (45/110, mg codlemone/mg pear ester) during the second generation in 2007 and the combo dispensers TRE144 (45/75) and TRE145 (75/45) during the first generation in 2008 compared with Isomate-C Plus. Similarly, male catches in female-baited traps in plots treated with the combo dispensers TRE144 during the first generation in 2008 and TRE23 (75/110) during the second generation, in 2007 were significantly lower than in plots treated with Isomate-C Plus. No significant differences were found for male catches in codlemone-baited traps in plots treated with Isomate-C Plus and any of the combo dispensers. However, male catches were significantly lower in plots treated with Cidetrak CM (codlemone-only dispenser) than the combo TRE144 dispenser during both generations in 2009.     

Female‐targeted attractant containing pear ester for Synanthedon myopaeformis

When testing pear ester (ethyl‐2,4‐decadienoate) + acetic acid (PEAA) lures to catch codling moths, Cydia pomonella (L.) (Lepidoptera: Tortricidae), in Hungary, significant catches of the apple clearwing moth, Synanthedon myopaeformis (Borkhausen) (Lepidoptera: Sesiidae), were also recorded. This sesiid is one of the most important pests of apple in Europe. Pear ester plus acetic acid lures were attractive to S. myopaeformis no matter whether the two compounds were provided in separate dispensers or mixed together in a single dispenser, and a large percentage (40–80%) of the clearwing moths caught were females. In all cases, traps baited with binary combinations of PEAA caught far more than traps baited with either of the compounds presented alone. Traps with PEAA lures in some tests caught (females and males together) up to ca. 20% of the catch in traps baited with the synthetic apple clearwing moth sex attractant (all males). Consequently, the PEAA lure shows potential for future practical applications as a female‐targeted lure. To our knowledge, this is the first report of attractiveness of a lure containing pear ester for non‐tortricid Lepidoptera. Our finding suggests that the compound may be exploited as a host location stimulus by a wider array of insects than was indicated previously.     

Improved monitoring of female codling moth (Lepidoptera: Tortricidae) with pear ester plus acetic acid in sex pheromone-treated orchards

The performance of clear delta traps baited with 3.0 mg of pear ester, ethyl (E,Z)-2,4-decadienoate, and 5.0 ml of acetic acid in separate lures was compared with orange delta traps baited with a single lure containing 3.0 mg of both pear ester and the sex pheromone, (E,E)-8,10-dodecadien-1-ol (codlemone) for codling moth, Cydia pomonella (L.), in apple, Malus domestica (Borkhausen). Residual analyses and field tests demonstrated that both the pear ester and acetic acid lures were effective for at least 8 wk. The two trap-lure combinations caught a similar number of total moths in an orchard treated with sex pheromone dispensers during short-term trials in 2008. However, the mean catch of female moths was significantly higher and male moths significantly lower in clear traps baited with pear ester and acetic acid versus orange traps baited with pear ester and codlemone. Season-long studies were conducted with these two trap-lure combinations in orchards treated with (n = 6) and without (n = 7) sex pheromone dispensers during 2009. The two trap-lure combinations caught similar numbers of moths in dispenser-treated orchards. In contrast, total catch was significantly higher (>2-fold) in the orange compared with the clear traps in untreated orchards. The clear caught >6-fold more females than the orange trap in both types of orchards. These studies suggest that deploying clear delta traps baited with pear ester and acetic acid can be an effective monitoring tool for female codling moth and an alternative to codlemone-baited traps in sex pheromone-treated orchards.     

Traps baited with pear ester and acetic acid attract both sexes of Hedya nubiferana (Lepidoptera: Tortricidae)

This study was initiated with the objective of studying field responses of the green budworm moth, Hedya nubiferana (Haworth) (Lepidoptera: Tortricidae), to pear ester [PE; ethyl (E,Z)‐2,4‐decadienoate] and acetic acid (AA) with the aim of developing a lure attractive also for females. In the overwhelming majority of tests, traps baited with the PEAA lure (the combination of both PE and AA) caught more than traps baited with either of the constituents presented alone. PEAA lures were attractive to H. nubiferana no matter whether the two compounds were provided in separate dispensers or mixed together in a single one, and a large percentage (up to 71%) of trap catch consisted of females. Traps with PEAA lures caught (females plus males) on an average 30% of the catches in traps baited with the synthetic green budworm moth sex pheromone (only males). This suggested that the new PEAA lure had a trapping performance comparable with that of pheromone traps, which latter are used by farmers today. Consequently, the PEAA lure showed potential for future practical applications as a female‐targeted lure for H. nubiferana. To our knowledge, this is the first well‐documented report on the attraction of PEAA lure for a tortricid species other than codling moth.     

Long‐term evaluation of field‐wide oriental beetle (Col., Scarabaeidae) mating disruption in blueberries using female‐mimic pheromone lures

The oriental beetle, Anomala orientalis (Waterhouse) (Col., Scarabaeidae), is the most important root‐feeding pest of blueberries and turfgrass in New Jersey, USA. Previous studies showed that mating disruption is a feasible option for oriental beetle management; however, assessing its efficiency can be challenging, and little is known on its long‐term effects. Accordingly, we conducted studies to investigate low‐dose pheromone lures equivalent to oriental beetle females (i.e. female mimics) as easy‐to‐use indicators of mating disruption success, determine the distance at which oriental beetle males respond to female‐mimic lures and assess the long‐term (3‐year) effects of mating disruption on oriental beetle populations in entire blueberry fields. Our studies showed that rubber septa baited with 0.3 μg of the oriental beetle sex pheromone (Z)‐7‐tetradecen‐2‐one attract similar numbers of males as compared with virgin females and can thus be used as a female mimic. The range of attraction of this lure was found to be also similar to virgin females and <30 m. In blueberries, mating disruption provided 87% inhibition of oriental beetle populations (trap shutdown) over a 3‐year period. Oriental beetle male captures in disrupted fields were threefold higher along the field edges than in the field interiors, indicating movement of males from nearby areas into the pheromone‐treated fields. In addition, mating disruption reduced male attraction to female‐mimic lures by 93% in all 3 years and reduced the number of larvae in sentinel potted plants in 1 of 2 years. These results show for the first time that mating disruption provides consistent long‐term field‐wide control of oriental beetle populations and that female‐mimic pheromone lures can be used as a new tool to assess oriental beetle mating disruption success.     

Developing female removal for Cydia pomonella (Lepidoptera: Tortricidae) in organic pear in the USA and Italy

Seventeen trials were conducted using traps baited with kairomone-based lures to evaluate female removal (FR) as an effective management tactic for codling moth, Cydia pomonella, L., in organic pear, Pyrus communis L., production in Italy and USA during 2019–2020. Studies included paired plots (0.4–1.4 ha) treated with or without 60 traps ha⁻¹ in cultivars Bartlett and Abate Fétel. Paired plots were also treated together with or without mating disruption (MD) and with similar spray programmes. Three-, four-, and five-component lures were used with several trap types: green, clear or green/white bucket traps and orange delta traps. The three-component lure consisted of (E,E)-8,10-dodecadien-1-ol (sex pheromone, PH), (E,Z)-2,4-ethyl decadienoate (pear ester, PE) and acetic acid (AA); the four-component lure was PE, (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), 6-ethenyl-2,2,6-trimethyloxan-3-ol (pyranoid linalool oxide, LOX), and AA, and the five-component lure had PH added. Preliminary studies were also conducted to evaluate the trapping efficacy of non-saturating bucket traps. A clear bucket trap baited with PE/DMNT/LOX + AA captured 97-fold more codling moth females than an orange delta trap baited with PH/PE. However, female captures did not differ between traps when both were baited with the four-component lure. Fruit injury from codling moth was significantly reduced with the implementation of FR in both pear production regions. At harvest, mean fruit protection in the USA studies was 65% and 27% in Italy. This difference was likely associated with the four-component lure being less effective in Italy than in the USA. Nevertheless, results demonstrate that FR can be a useful approach to remove females immigrating into orchards and as a new tactic to reduce pest pressure in selected areas of orchards allowing both MD and organic insecticide programmes to be more effective. Further studies should investigate the cost-benefit of matching the intensity of FR to variable pest pressures.     

Monitoring codling moth (Lepidoptera: Tortricidae) in orchards treated with pear ester and sex pheromone combo dispensers

Monitoring codling moth, Cydia pomonella (L.), with its sex pheromone (E,E)‐8,10‐dodecadien‐1‐ol (codlemone) alone or in combination with plant volatiles (PH‐plant volatile lures) with and without the addition of an acetic acid (AA) lure was compared in apple and walnut orchards treated with PVC Cidetrak^® dispensers (CM‐DA Combo) loaded with 60 mg pear ester, ethyl (E, Z)‐2,4‐decadienoate (PE) and 185 mg codlemone. Lures were also evaluated in untreated apple and walnut orchards and apple orchards treated with Cidetrak^® dispensers (CM) loaded with 120 mg codlemone. Traps with codlemone lures caught more moths than PE plus AA but similar numbers as traps with the PH‐PE lure in untreated apple and walnut orchards. The PH‐PE outperformed codlemone lures in apple orchards treated with CM dispensers. Codlemone outperformed PH‐PE lures in apple but not in walnut orchards treated mid‐season with CM‐DA Combo dispensers. Combining AA with PE significantly increased moth catch and together they performed similarly to the PH‐PE lure in all dispenser treatments in apple orchards. However, adding AA with the PH‐PE lure did not increase moth catches. The addition of AA to any of the lures tested except codlemone alone significantly increased the catch of females. Adding AA to either PE or the PH‐PE lure created a similarly attractive lure in orchards treated with CM‐DA Combo dispensers. Combining (E)‐4,8‐dimethyl‐1,3,7‐nonatriene (DMNT) with codlemone in a combinational lure plus AA performed as well as any lure tested in apple orchards treated with CM‐DA Combo dispensers. Combinational lures loaded with either (E,E)‐farnesol, (E)‐β‐farnesene or DMNT performed significantly better than the PH‐PE lure in apple orchards treated with CM‐DA Combo dispensers only in the first generation. Both PH‐DMNT and PH‐farnesol lures were comparable to PH‐PE, except that the PH‐farnesol lure was less attractive to female moths.     

Effect of anti‐hail nets on Cydia pomonella behavior in apple orchards

Over the last 10 years, the use of nets to protect pome fruit from hailstorms has increased. In this study, we investigated the effect of these nets on the behavior of the codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), a major pest of apple, Malus domestica Borkh. (Rosaceae). Experiments were carried out in net‐covered and uncovered apple orchards treated with conventional insecticides. The number of codling moth males caught in pheromone‐ and virgin female‐baited traps was significantly reduced in net‐covered compared to uncovered plots. In addition, inhibition of mating by the net was demonstrated by significant reductions in mating of tethered virgin females. Fruit injury was consistently lower in net‐covered plots vs. uncovered plots. Because of the reductions in male trap catch, the reduced female mating frequency, and the lower level of damage, we conclude that flat anti‐hail nets have a disruptive effect on the reproductive behavior of the codling moth.     

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.