Suppression of citrus leafminer, Phyllocnistis citrella, with an attract-and-kill formulation

The citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), is a worldwide pest of citrus crops and is responsible for proliferation of citrus bacterial canker, Xanthomonas axonopodis (Hasse) pv. citri (Gamma Proteobacteria: Xanthomonadaceae). We developed and evaluated an attracticide formulation, termed MalEx, for control of P. citrella. MalEx is a viscous paste with UV‐protective properties that is dispensed as 50‐μl droplets using custom‐made calibrated pumps. A formulation containing 0.016%P. citrella pheromone [3:1 blend of (Z,Z,E)‐7,11,13‐hexadecatrienal and (Z,Z)‐7,11‐hexadecadienal] and 6% permethrin was found to suppress male response to pheromone in the field better than formulations containing 10× less pheromone. Although formulations without permethrin showed some suppression of male activity because of mating disruption, addition of 6% permethrin to the formulation was required for optimal efficacy. When MalEx, containing 0.016% pheromone and 6% permethrin, was applied at 3 000 point sources ha^?1, the application height did not influence efficacy of male P. citrella suppression within mature 4‐m tall citrus trees. Decreasing the rate of MalEx from 3 000 to 1 500 droplets ha^?1 reduced efficacy as measured by both male P. citrella activity and larval infestation. Although 4 500 droplets ha^?1 did not result in statistically better efficacy than 3 000 droplets ha^?1, there was a noticeable trend for higher efficacy as droplet density increased. Continuous treatment of 0.5‐ha blocks of citrus with MalEx over the course of 112 days reduced larval infestation of new flush, as compared with those in untreated control plots, by 3.6–7.2× depending on droplet application density. In laboratory behavioral bioassays, the attractiveness of MalEx droplets to male P. citrella was drastically reduced after 21 days of field aging. However, our laboratory investigation confirmed that 100% of males contacting MalEx droplets, aged up to 35 days in the field, were killed within 24 h. Direct observation of male P. citrella behavior in the field confirmed that attracted males made contact with droplets. Control of P. citrella with MalEx should reduce the number of required broad spectrum sprays for leafminer management in both field and citrus nursery settings.     

Factors affecting captures of male citrus leafminer, Phyllocnistis citrella Stainton, in pheromone-baited traps

The citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), is an important world‐wide pest of citrus. Larval mining within leaf flush impacts yield and predisposes trees to infection by citrus canker, Xanthomonas axonopodis pv. citri. The present series of studies sought to identify factors affecting male P. citrella catch in pheromone‐baited traps with the intent of developing effective monitoring. A commercially available pheromone lure (Citralure, ISCA Technologies, Riverside, CA, USA) was highly effective in attracting male P. citrella to traps. Pherocon VI Delta (Trécé Inc., Adair, OK, USA) traps baited with a Citralure captured more male P. citrella than identically baited Pherocon IC Wing traps (Trécé Inc.). The superiority of the Delta‐style trap was found to be due to a 3 cm long closing latch that likely prevents males from flying directly through the trap without capture. Within canopies of mature citrus trees (approximately 3.5 m high), traps at mid‐canopy height (2.0 m) captured more males than traps placed higher (3.5 m) or lower (0.6 m). On the canopy perimeter and in between canopies, traps near ground level (0.6 m height) captured more males than traps at 2.0 and 3.5 m heights. Male catch was greater within the tree canopy or on the canopy perimeter than 2.0 away from the canopy. Traps deployed in trees on the edge of groves captured more males than traps placed 120 and 240 m away from the grove edge and within the grove interior. In non‐pheromone‐treated grove plots, the optimal dosage for catching males was between 0.1 and 1.0 mg of the 3 : 1 blend of (Z,Z,E)‐7,11,13‐hexadecatrienal and (Z,Z)‐7,11‐hexadecadienal; however, in pheromone‐treated plots a higher 10.0 mg dosage lure was most effective. Male catch in pheromone‐baited traps exhibited a diel rhythm with most males captured during scotophase (22:00–23:00 h) and no males captured during photophase.     

A novel pheromone dispenser for mating disruption of the leafminer Phyllocnistis citrella (Lepidoptera: Gracillariidae)

The sex pheromone of the leafminer Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) was deployed in a Florida citrus (Citrus spp.) grove by using a novel deployment device (IFM-413) containing SPLAT, a flowable formulation of an emulsified wax compound designed to provide slow release of semiochemicals. The device consisted of two disks connected by string. Each disk was loaded with 1 g of SPLAT containing either 0.15% (Z,Z,E)-7,11,13-hexadecatrienal (triene) or 2% (Z,Z)-7,11-hexadecadienal (diene). The devices were deployed using a two-dimensional multivariate design to determine the optimal rate of pheromone per unit area and degree of aggregation of the deployment devices (number of trees treated per unit area). The IFM-413 device proved effective at becoming securely entangled in tree branches. Furthermore, the devices effectively delivered pheromone-loaded SPLAT that resulted in disruption of trap catch of male P. citrella. Response surfaces showed a quadratic response of trap catch disruption to both total amount of pheromone per unit area and the degree of aggregation of the deployed devices (number of treated trees per unit area). The response surfaces for 0.15% triene or 2.0% diene were similar. The diene produced an effect similar to that of the triene at approximately 13 times the rate of the triene. The greatest disruption of trap catch occurred when the number of treated trees per unit area was greatest (no aggregation of deployment devices). Manufacturing, packaging, and mechanical deployment of the devices remain to be investigated.     

Optimization and field evaluation of the sex pheromone of Trichophysetis cretacea (Lepidoptera,Crambidae) for pest monitoring

Field studies using the synthetic sex pheromone of Trichophysetis cretacea, a trinary blend of (Z)‐11‐hexadecenyl acetate (Z11‐16:OAc), (Z)‐11‐hexadecenal (Z11‐16:Ald) and (Z)‐11‐hexadecenol (Z11‐16:OH), were performed in Sichuan to determine operational parameters for detection and control, such as dispenser type, blend ratio, dosage, and trap type, height and density. Of three pheromone dispensers tested, grey halo‐butyl isoprene elastomeric septa were significantly more effective than polyvinyl chloride capillary tubing or silicone rubber septa. The ratio of the three components in the blend significantly affected moth catch. In the halo‐butyl isoprene septa, the most effective ratio was 5 : 2 : 1 Z11‐16:OAc:Z11‐16:Ald:Z11‐16:OH. Sticky wing traps caught significantly more moths than water, noctuid moth or cone funnel traps. The most effective height at which wing traps were hung was 20 cm above the jasmine plants. Optimum trap density was 45 traps per hectare. Addition of volatile jasmine compounds did not increase the attractiveness of the sex pheromone. A dosage of 50 μg Z11‐16:OAc per lure was most effective in the autumn weather conditions of Quanwei. These data provide sufficient information to develop effective protocols for using the T. cretacea pheromone to detect and monitor this pest in the jasmine fields.     

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.     

Five years of mass trapping of Ephestia kuehniella Zeller: a component of IPM in a flour mill

Results obtained by mass trapping using the synthetic pheromone (Z,E)‐9,12‐tetradecadienyl acetate (TDA) are reported. The trapping was carried out over a period of 5 years to control infestation by Mediterranean flour moth, Ephestia kuehniella Zeller, and protect a flour mill. From March 2004 till November 2008, 42 funnel traps, each baited with 2 mg of TDA, were placed in the mill. Eight additional traps were located at the exterior of the facility, especially in the wheat silo area and near the loading equipment. Over 5 years, the pheromone traps attracted a total of 54 170 male Mediterranean flour moths. The constant presence of the traps caused a marked decrease in the E. kuehniella population from 2004 to 2008. The results of the surveys show that the population density of the moth can be notably reduced and then maintained at a low level in flour mills by means of mass trapping techniques accompanied by localized insecticide treatments and careful cleaning of the various departments and of the interior of all equipment. As it is not possible at present to establish the economic injury level of insect infestation in flour mills, there is a need for investigations into how the effectiveness of IPM programs can be evaluated in more detail.     

Comparison of three dispenser distribution patterns for pheromone mating disruption of Paralobesia viteana (Lepidoptera: Tortricidae) in vineyards

Over two growing seasons, Isomate GBM-Plus tube-type dispensers releasing the major pheromone component of grape berry moth, Paralobesia viteana (Clemens) (Lepidoptera: Tortricidae), were evaluated in vineyards (Vitis spp.) in Michigan, New York, and Pennsylvania. Dispensers were deployed in three different density-arrangement treatments: 124 dispensers per ha, 494 dispensers per ha, and a combined treatment with 124 dispensers per ha in the vineyard interior and 988 dispensers per ha at the vineyard border, equivalent to an overall density of 494 dispensers per ha. Moth captures and cluster infestation levels were compared at the perimeter and interior of vineyards receiving these different pheromone treatments and in vineyards receiving no pheromone. Orientation of male moths to pheromone-baited traps positioned at the perimeter and interior of vineyards was reduced as a result of mating disruption treatments compared with the nontreated control. These findings were consistent over both years of the study. Disruption of male moth captures in traps varied from 93 to 100% in treated vineyards, with the 494 dispensers per ha application rates providing significantly higher level of disruption than the 124 dispensers per ha rate, but only in 2007. Measurements of percentage of cluster infestation indicated much higher infestation at perimeters than in the interior of the vineyards in all three regions, but in both sample positions there was no significant effect of dispenser density on cluster infestation levels in either year. The contrasting results of high disruption of moth orientation to traps in vineyards that also had low levels of crop protection from this pheromone treatment are discussed in the context of strategies to improve mating disruption of this tortricid pest.     

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.     

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.     

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.     

Controlling infestation of a chocolate factory by Plodia interpunctella by combining mating disruption and the parasitoid Habrobracon hebetor

A field experiment of 4 years’ duration was carried out to evaluate the efficacy of combining the mating disruption (MD) formulation Dismate ZETA ((9Z,12E)‐tetradecadienyl acetate), with the parasitoid Habrobracon hebetor against the Indianmeal moth Plodia interpunctella in a chocolate factory. The experimental period began early in 2011 and ended in late 2014. Begane Dismate dispensers were placed in the facility from 2011 to 2014 and H. hebetor was released in 2014. Pheromone‐baited traps were used to monitor the flight activity of the male moths and oviposition Petri dish traps were placed to assess the progeny production of P. interpunctella females. Following the start of MD, a decrease in the number of P. interpunctella males caught in monitoring traps was observed from 2011 to 2013. A further decline in the moth population was noted in 2014, when MD was combined with the release of parasitoids. The presence of larvae in the oviposition cups was occasionally observed throughout the monitoring period, from 2011 to 2014. This study demonstrates that the combined system of MD and parasitoids is an effective and reliable technique that can be used to successfully control P. interpunctella.     

Sex pheromone of the red clover casebearer moth,Coleophora deauratella,an invasive pest of clover in Canada

The red clover casebearer, Coleophora deauratella Lienig & Zeller (Lepidoptera: Coleophoridae), is an invasive pest of Trifolium species (Fabaceae) in Canada. We identified candidate sex pheromone components from female pheromone gland extracts using coupled gas chromatographic–electroantennographic analysis detection. Three compounds elicited an electrophysiological response from antennae and were identified as: (Z)‐7‐dodecenyl acetate, (Z)‐5‐dodecenyl acetate, and (Z)‐7‐dodecen‐1‐ol. Field tests of the candidate pheromone components revealed that males were attracted to a binary mixture of (Z)‐7‐dodecenyl acetate and (Z)‐5‐dodecenyl acetate. Male moth trap capture was greatest in traps baited with lures containing 100:10 or 100:20 ratios of these pheromone components, respectively. Trap capture was reduced when (Z)‐5‐dodecenyl acetate was present below 10 or above 20% of (Z)‐7‐dodecenyl acetate. Equal numbers of male moths were captured in traps baited with 10, 100, and 1 000 μg of the attractive binary mixture. These findings allow for the development of a pheromone‐based monitoring system for this invasive pest of clover in Canada.     

Improved monitoring of oriental fruit moth (Lepidoptera: Tortricidae) with terpinyl acetate plus acetic acid membrane lures

Male and female moth catches of Grapholita molesta (Busck) in traps were evaluated in stone and pome fruit orchards untreated or treated with sex pheromones for mating disruption in Uruguay, Argentina, Chile, USA, and Italy from 2015 to 2017. Trials evaluated various blends loaded into either membrane cup lures or septa. Membrane lures were loaded with terpinyl acetate (TA), acetic acid (AA) and (Z)‐3‐hexenyl acetate alone or in combinations. Two septa lures were loaded with either the three‐component sex pheromone blend for G. molesta alone or in combination with codlemone (2‐PH), the sex pheromone of Cydia pomonella (L). A third septum lure included the combination sex pheromone blend plus pear ester, (E,Z)‐2,4‐ethyl decadienoate (2‐PH/PE), and a fourth septum was loaded with only β‐ocimene. Results were consistent across geographical areas showing that the addition of β‐ocimene or (Z)‐3‐hexenyl acetate did not increase moth catches. The addition of pear ester to the sex pheromone lure marginally increased moth catches. The use of TA and AA together significantly increased moth catches compared with the use of only one of the two components. Traps with the TA/AA lure outperformed the Ajar trap baited with a liquid TA plus sugar bait. The emission rate of AA was not a significant factor affecting the performance of the TA/AA lure. The addition of TA/AA significantly increased moth catches when combined with the 2‐PH lure. The TA/AA lure also allowed traps to catch both sexes. Catch of C. pomonella with the 2‐PH lure was comparable to the use of codlemone; however, moth catch was significantly reduced with the 2‐PH/PE lure. Optimization of these complex lures can likely further improve managers’ ability to monitor G. molesta and help to develop multispecies tortricid lures for use in individual traps.     

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.     

Efficacy of the pheromone (3Z)‐lactone and the host kairomone (3Z)‐hexenol at detecting early infestation of the emerald ash borer,Agrilus planipennis

The invasive emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is a major pest of ash trees, Fraxinus spp., in its introduced range in North America. Field studies were conducted to quantify the efficacy of traps baited with kairomone and pheromone lures for early detection of A. planipennis infestation. A trapping experiment demonstrated that green traps baited with the kairomone (3Z)‐hexenol detected at least one adult A. planipennis in 55.3% of plots with ‘nil to low’‐density infestations and in 100% of plots with ‘moderate to high’‐density A. planipennis infestations. Mean trap captures increased significantly with increasing infestation density. In terms of the optimal number of traps per plot, when one (3Z)‐hexenol‐baited trap was placed per plot, the trap detected populations in 62% of the plots with ‘low to moderate’‐density infestations through branch sampling. Detectability was increased to 82% when two traps were placed per plot. Finally, addition of female‐produced (3Z)‐lactone pheromone to traps significantly increased detection rates at both the trap and plot level, as compared with traps baited with the host volatile, (3Z)‐hexenol, alone (88 vs. 60%, respectively). Our results are the first to demonstrate the efficacy of baited green sticky traps for detecting low‐density A. planipennis infestations, particularly when the (3Z)‐lactone pheromone is used. This combination is therefore recommended for development of early‐detection protocols against A. planipennis.     

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.     

Odour quality discrimination for behavioural antagonist compounds in three tortricid species

The antennal and behavioural response of three tortricid species (Lepidoptera: Tortricidae) to their corresponding sex pheromones and known or putative behavioural antagonists was tested by electroantennography and in field trials. The species and their pheromones and known or proposed behavioural antagonist were lightbrown apple moth, Epiphyas postvittana (Walker) [pheromone: 95% (E)‐11‐tetradecenyl acetate (E11‐14Ac) and 5% (E,E)‐9,11‐tetradecadienyl acetate (E9E11‐14Ac); antagonist: (Z)‐11‐tetradecenyl acetate (Z11‐14Ac)], codling moth, Cydia pomonella (L.) [pheromone: (E,E)‐8,10‐dodecadien‐1‐ol (codlemone); antagonist: (E,E)‐8,10‐dodecadienyl acetate (codlemone acetate)], and gorse pod moth, Cydia ulicetana (Haworth) [pheromone: (E,E)‐8,10‐dodecadienyl acetate (codlemone acetate); putative antagonist: (E,E)‐8,10‐dodecadien‐1‐ol (codlemone)]. In all three species, the antennal response to the antagonists was not significantly different from the antennal response to con‐specific sex pheromone compounds. In the field trapping experiments, significantly fewer males of all three species were attracted to the respective pheromone when blended with the behavioural antagonist compound. However, this response varied between the species, with lightbrown apple moth and codling moth showing stronger responses to the antagonist compounds than gorse pod moth. Both lightbrown apple moth and codling moth males were able to discriminate between pure pheromone and pheromone blended with the antagonist when placed in traps side‐by‐side separated by ca. 10 cm. The presence of the behavioural antagonist not only affected the catch of males of both species within their own traps but also affected the catch in the neighbouring trap that contained con‐specific sex pheromone; the catch of gorse pod moth was not reduced by the presence of codlemone in the neighbouring trap. These results suggest that strong behavioural antagonists such as codlemone acetate for codling moth and Z11‐14Ac for lightbrown apple moth induce their inhibition effect at a substantial distance downwind from the odour source; however, most of those males that were able to overcome this inhibition effect at the early stage of orientation to odour source, were able to discriminate between the pheromone source and the pheromone source admixed with behavioural antagonist. Moderate behavioural antagonists such as codlemone for gorse pod moth did not elicit a discrimination effect.     

Developing pheromone traps and lures for Maruca vitrata in Benin, West Africa

In previous work successful trapping of the legume podborer, Maruca vitrata Fabricius (Lepidoptera: Pyralidae), was accomplished using a synthetic pheromone blend consisting of (E,E)‐10,12‐hexadecadienal, (E,E)‐10,12‐hexadecadienol, and (E)‐10‐hexadecenal in a 100 : 5 : 5 ratio. In the present work, experiments were conducted in cowpea fields in Benin to compare different trap designs, and other aspects of the lures. A water‐trap made from a plastic jerry‐can was found to be superior to commercial funnel‐ and sticky‐trap designs, and 120 cm was the optimum height for captures. Generally, lures consisted of polyethylene vials containing 0.1 mg of pheromone. Results showed that shielding the lures from the adverse effects of sunlight with aluminium foil did not increase trap catches of M. vitrata. The degree of isomeric purity of the (E,E)‐10,12‐hexadecadienal and (E,E)‐10,12‐hexadecadienol blend components, in the range 73–99%, had no significant effect on captures, while lures of 80% isomeric purity showed no loss of effectiveness for up to 4 weeks. Similar results were observed with lures from a commercial source containing 0.46 mg of pheromone in the blend ratio 100 : 11 : 6 and 95% isomeric purity. Residue analysis showed that vial lures exposed for 2 weeks in the field still contained 73% of the initial amount of (E,E)‐10,12‐hexadecadienal, compared to rubber septa dispensers, which only retained 22%. Females comprised 11–50% of total catches, confirming earlier, unexpected results for synthetic lures. The observations that effective traps can be made from locally available plastic containers, and that pheromone blend composition and purity are not critical, should reduce costs and improve the feasibility of traps as practical monitoring tools for M. vitrata.     

Mass‐trapping trials for the control of pine processionary moth in a pine woodland recreational area

The pine processionary moth, Thaumetopoea pityocampa, causes serious defoliation to Cedrus, Pinus and Pseudotsuga trees, as well as health problems in humans, pets and farm animals due to their urticating hairs. Environmentally friendly strategies for the management of T. pityocampa include: removal of egg batches, removal of nests, trapping of migrant larvae, spraying microbial or Insect Growth Regulator (IGR) insecticides and biocontrol, as well as pheromone‐based adult trapping and mating‐disruption. In the present paper, results on innovative technology for the control of T. pityocampa infestation using pheromone mass‐trapping are reported. Two 1‐ha plots were identified in the study area (central‐south Italy), a pine woodland recreational site growing Pinus halepensis. In the experimental plot (MT‐plot), 10 G‐traps (funnel trap type) baited with (Z)‐13‐hexadecen‐11‐ynyl acetate sex pheromone component were placed for mass‐trapping of adults; the other plot was used as a control‐plot (C‐plot). The T. pityocampa population was monitored using the two central traps in the MT‐plot and two traps positioned in the C‐plot. In addition, the winter nests made by T. pityocampa larvae overwintering on pine trees were counted. After 2 years of mass‐trapping, the number of adults trapped by the monitoring pheromone traps decreased in the MT‐plot, but not in the C‐plot, whereas the number of nests decreased in both plots. Statistical results highlighted significant differences in trap catches between the two plots but not between years. In the case of nests, differences among plots were not significant before the mass‐trapping, but significant after 1‐year treatment. According to our results, the mass‐trapping technique is able to reduce T. pityocampa infestations. This pheromone method can be applied in combination with other control systems in the context of integrated pest management in recreational areas.     

Pheromone pre-exposure and mating modulate codling moth (Lepidoptera: Tortricidae) response to host plant volatiles

Abstract 1 Two codling moth Cydia pomonella kairomonal attractants, ethyl (E,Z)‐2,4‐decadienoate (pear ester) and (E)‐β‐farnesene, were tested in an insecticide‐sprayed apple orchard and an orchard treated for mating disruption with synthetic pheromone (E,E)‐8,10‐dodecadienol (codlemone). Male captures with pear ester were higher in the pheromone‐treated than in the insecticide‐treated orchard, whereas captures with (E)‐β‐farnesene were not different. Subsequent wind tunnel experiments confirmed that pre‐exposure to sex pheromone codlemone increased the behavioural response of codling moth males to pear ester. This supports the idea that male attraction to the plant volatile pear ester and sex pheromone codlemone is mediated through the same sensory channels. 2 Pear ester is a bisexual codling moth attractant and even captures of female moths were significantly increased in the pheromone‐treated orchard. In the laboratory wind tunnel, pheromone pre‐exposure had no effect on female response to pear ester, but significantly more mated than unmated codling moth females flew upwind towards a pear ester source. Differences in mating status in insecticide‐treated vs. pheromone‐treated orchards may thus account for the differences in female trap captures with pear ester. 3 These findings are important with respect to monitoring of codling moth with pear ester in mating disruption orchards. They also emphasize the importance of host plant volatiles in pheromone‐mediated mating disruption, which has been neglected to date.