Monitoring oriental fruit moth (Lepidoptera: Tortricidae) with the Ajar bait trap in orchards under mating disruption

Studies in Oregon, California, Pennsylvania and Italy evaluated the relative performance of the Ajar trap compared with several other traps for the capture of Grapholita molesta (Busck), in pome and stone fruit orchards treated with sex pheromone dispensers for mating disruption. The Ajar is a delta‐shaped trap with a screened jar filled with an aqueous terpinyl acetate plus brown sugar bait solution (TAS) that opens inside the trap and is surrounded by a sticky liner. The TAS‐baited Ajar trap was evaluated with and without the addition of a sex pheromone lure and compared with a delta trap baited with a sex pheromone lure and a bucket trap filled with the TAS bait. Although the Ajar trap had a 90% lower evaporation of the TAS bait than the bucket trap, both of them caught similar numbers in the majority of the field tests of both sexes of G. molesta. The addition of the sex pheromone lure did not increase moth catches by the TAS‐baited Ajar trap. The TAS‐baited Ajar trap caught significantly greater numbers of moths than the sex pheromone‐baited delta trap in 18 of the 20 orchards. Few hymenopterans were caught in orange TAS‐baited Ajar traps, but the catch of flies and other moths relative to the target pest remained high. Flight tunnel and field tests evaluated the effect of several screen designs on the catches of G. molesta and non‐target species. All exclusion devices significantly reduced the catch of larger moths. However, designs that did not reduce the catch of male G. molesta did not reduce the catch of muscid flies. Exclusion devices with openings <7.0 mm significantly reduced the catch of female G. molesta. The addition of (E)‐β‐farnesene, (E)‐β‐ocimene or butyl hexanoate septa lures to TAS‐baited Ajar traps significantly increased total moth catch. The addition of (E)‐β‐ocimene also significantly increased female moth catch.     

Monitoring oriental fruit moth and codling moth (Lepidoptera: Tortricidae) with combinations of pheromones and kairomones

Experiments were conducted in North and South America during 2012–2013 to evaluate the use of lure combinations of sex pheromones (PH), host plant volatiles (HPVs) and food baits in traps to capture the oriental fruit moth, Grapholita molesta (Busck), and codling moth, Cydia pomonella (L.), in pome and stone fruit orchards treated with sex pheromones. The combination of the sex pheromone of both species (PH combo lure) significantly increased G. molesta and marginally decreased C. pomonella captures as compared with captures of each species with either of their sex pheromones alone. The addition of a HPV combination lure [(E,Z)‐2,4‐ethyl decadienoate plus (E)‐β‐ocimene] or acetic acid used alone or together did not significantly increase the catch of either species in traps with the PH combo lure. The Ajar trap baited with terpinyl acetate and brown sugar (TAS bait) caught significantly more G. molesta than the delta trap baited with PH combo plus acetic acid in California during 2012. The addition of a PH combo lure to an Ajar trap significantly increased catches of G. molesta compared to the use of the TAS bait or PH combo lure alone in 2013. Female G. molesta were caught in TAS‐baited Ajar traps at similar levels with or without the use of additional lures. Ajar traps baited with the TAS bait alone or with (E)‐β‐ocimene and/or PH combo lures caught significantly fewer C. pomonella than delta traps with sex pheromone alone. Ajar traps with 6.4‐mm screened flaps caught similar numbers of total and female G. molesta as similarly baited open Ajar traps, and with a significant reduction in the catch of non‐targets. Broader testing of HPV and PH combo lures for G. molesta in either delta or screened or open Ajar traps is warranted.     

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.     

Effects of different sex pheromone compositions and host plants on the mating behavior of two Grapholita species

The two congener species Grapholita molesta and Grapholita dimorpha share two major sex pheromone components: cis-8-dodecenyl acetate (Z8-12Ac) and trans-8-dodecenyl acetate (E8-12Ac). In fact, commercial sex pheromone lures composed of only these two major components attract the males of both species. In this study, we aimed to determine the reproductive isolation components of these two species by analyzing the effects of the minor sex pheromone components and host plants. First, different ratios of the two major sex pheromone components were greatly favored by either male species. Sex pheromone gland extracts of G. dimorpha contained a lesser proportion of Z8-12Ac than that of G. molesta. In the three (apple, pear, and peach) orchards investigated in this study, a larger number of G. molesta males were attracted to the 95:5 pheromone mixture (Z8-12Ac and E8-12Ac, respectively), while a larger number of G. dimorpha males were attracted to the 85:15 mixture. Second, there was a significant variation in male attractions in different host plants. G. molesta males were more attracted to the sex pheromone lure in the apple orchards than that in the pear and peach orchards. In contrast, G. dimorpha males were more attracted to the lures in the pear and peach orchards than that in the apple orchard. Third, the minor sex pheromone components were important for reproductive isolation. Among the four minor components tested, addition of (Z)-8-dodecenol (Z8-12OH) to the major sex pheromone components significantly suppressed male attraction in G. dimorpha and slightly elevated male attraction in G. molesta. The discriminating effect of Z8-12OH was further validated using male electroantennogram analysis. These results suggest that reproductive isolation between two congeners can be achieved by variations in the minor sex pheromone components and in the host plants, as well as by changes in the ratio of the two major components.     

Factors influencing adult male Grapholita molesta dispersal in commercial Malus and Prunus host crops

The oriental fruit moth (OFM), Grapholita molesta (Busck) (Lepidoptera: Tortricidae), has been an economic pest of apples (Malus spp.) and peaches (Prunus spp.; both Rosaceae) in the eastern USA since the 1930s. Successful management of G. molesta with insecticides requires careful timing of these products based on sex‐pheromone trap captures of male moths. In Pennsylvania, apple and peach orchards are often planted adjacently. Factors such as trap distance from release points, host crop, and wind were considered in relation to male moth movement within and between hosts. Our practical objective was to understand male G. molesta dispersal within and between these two hosts to achieve better management. Recapture of moths decreased over distance; the majority of moths were recaptured 50–100 m from the release point regardless of crop type. Male G. molesta released into commercial apple and peach orchards were most likely to remain in the crop of release and to not exhibit host shifts over the season, even after peach fruit were harvested. Our analyses of wind direction data with respect to recapture showed that the likelihood of recapture was similar regardless of the orientation of the traps relative to the mean wind direction at peak flight times. The apple and peach host crops appeared to affect male G. molesta dispersal to the extent that wind in orchards affects their perception of pheromone. Crop effects were most likely due to the traps closest to the release points being in the same crop as the release points.     

Variability in the efficacy of sex pheromone lures for monitoring oriental fruit moth (Lepidoptera: Tortricidae)

Studies were conducted in Chile and the United States to compare the attractiveness of various commercial sex pheromone lures and two experimental lures for oriental fruit moth, Grapholita molesta (Busck), in peach orchards treated with or without sex pheromone dispensers. The experimental lures contained the three‐component sex pheromone blend of G. molesta: Z‐8‐dodecenyl acetate, E‐8‐dodecenyl acetate and Z‐8‐dodecenol (Z8‐12:OH), and the sex pheromone of codling moth, Cydia pomonella (L.), (E,E)‐8,10‐dodecadien‐1‐ol, (codlemone). Commercial lures varied in their substrate, initial loading and blend ratio of components. Significant differences in male catches were found among commercial lures in orchards treated with or without sex pheromone dispensers. Experimental lures with the addition of codlemone significantly increased the catches of G. molesta using lures loaded with 0%, 1% or 5% Z8‐12:OH in the G. molesta blend compared with the same ratio of components in just the G. molesta blend. The experimental lures were significantly more attractive than all commercial lures in the untreated orchard. However, moth catch with the experimental lures in the sex pheromone‐treated orchard was only intermediate among all of the lures tested. These findings highlight the need to develop more effective and standardized lures that can be used in trap‐based monitoring programme for this important pest.     

Model of Grapholita molesta spring emergence in pear orchards based on statistical information criteria

The oriental fruit moth, Grapholita molesta, is becoming a large threat to Korean pear production. Timely management of the egg and early larval stages from the spring emergence is critical to reduce the G. molesta population during the pear growing season. A model was developed to precisely predict the spring occurrence of G. molesta adults as a function of accumulated degree-days. The model was validated with male moth caught in sex pheromone-baited traps placed in pear orchards at two major pear production regions (Icheon and Naju) of Korea in 2010. We applied nine distribution models to describe the cumulative proportions of G. molesta males caught relative to accumulated degree-days. The observed phenology of the G. molesta spring population was well described by the nine models. The predicted dates for the cumulative 50% male moth catches were within a 5 day period. Based on statistical information criteria (Akaike's and Bayes–Schwartz information criteria), we recommend the sigmoid function referred by Brown and Mayer, because of its ease of use and meaningfulness; the parameter “b” denotes the degree-day accumulation at 50% moth emergence. The G. molesta spring emergence model could be applied to determine optimal chemical treatment timing for controlling G. molesta in fruit tree orchards and further help to develop a full-cycle phenology model of G. molesta.     

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.     

Monitoring oriental fruit moth (Lepidoptera: Tortricidae) with sticky traps baited with terpinyl acetate and sex pheromone

Studies in Argentina and Chile during 2010–2011 evaluated a new trap (Ajar) for monitoring the oriental fruit moth, Grapholita molesta (Busck). The Ajar trap was delta‐shaped with a jar filled with a terpinyl acetate plus brown sugar bait attached to the bottom centre of the trap. The screened lid of the jar was inserted inside the trap, and moths were caught on a sticky insert surrounding the lid. The Ajar trap was evaluated with and without the addition of a sex pheromone lure and compared with delta traps left unbaited or baited with a sex pheromone lure and a bucket trap filled with the same liquid bait. Studies were conducted in a sex pheromone‐treated orchard in Argentina and an untreated orchard in Chile. In Chile, the Ajar trap without the sex pheromone lure caught significantly fewer males, females and total moths than the bucket trap, and fewer males and more females than the sex pheromone‐baited delta trap. Total moth catch did not differ between the Ajar trap without a sex pheromone lure and the sex pheromone‐baited trap. Adding a sex pheromone lure to the Ajar trap significantly increased total moth catches to levels not different from those in the bucket trap. However, the Ajar trap with the sex pheromone lure caught significantly more males and fewer females than the bucket trap. In Argentina, the Ajar trap with or without the addition of a sex pheromone lure caught similar numbers of both sexes and total moths as the bucket trap. The sex pheromone‐baited delta trap caught <4% of the number of moths as these three traps. The bucket trap in both studies caught significantly more non‐targets than the delta and Ajar traps. Moth catches in the Ajar trap declined significantly after 2–3 weeks when the bait was not replaced.     

Evaluation of the synthetic sex pheromone of the obscure mealybug,Pseudococcus viburni,as an attractant to conspecific males,and to females of the parasitoid Acerophagus maculipennis

The obscure mealybug, Pseudococcus viburni (Signoret) (Hemiptera: Pseudococcidae), is a cosmopolitan pest. In New Zealand, recently introduced management tools include the host‐specific parasitoid Acerophagus maculipennis (Mercet) (Hymenoptera: Encyrtidae) established in 2001, and pheromone‐baited monitoring traps available since 2005. Red delta traps baited with rubber septum lures impregnated with 4.0 μg of the mealybug synthetic sex pheromone, placed in apple orchards in Hawke's Bay and Nelson, trapped both male P. viburni and female A. maculipennis. Two generations of both species per year were discernible, but numbers were low in spring and parasitoids were not trapped during winter (June to September). Male P. viburni catches reached a plateau at a pheromone dose of ca. 1.0 μg per lure but numbers of A. maculipennis per trap increased up to 100 μg per lure, the maximum dose tested. A mathematical model showed that the lures had a half‐life of about 7.4 days and were most attractive to P. viburni with a dose of 0.19 μg, and that the trap effectiveness decreased rapidly once the release rate dropped below the optimum. The model also predicted that the initial pheromone dose should be increased from 0.19 to 5.41 μg per lure as the desired period of deployment increased from 0 to 9 weeks. A dose of 4.0 μg had an initial relative effectiveness of about 55%, reached peak effectiveness after about 5 weeks, and fell to 55% relative effectiveness again after about 8.3 weeks. We conclude that an initial pheromone load of 4.0 μg is appropriate for practical monitoring of P. viburni during the New Zealand summer. Future applications of the sex pheromone for managing the pest and parasitoid are discussed.     

Different types of fruit damages of three internal apple feeders diagnosed with mitochondrial molecular markers

Three tortricid pests, Grapholita dimorpha (Komai), G. molesta (Busck), and Carposina sasakii (Matsumura), are known as internal apple feeders in Korea. To identify young larvae, this study developed two types of molecular markers from their mitochondrial DNA (mtDNA) sequences. To this end, six different loci of mtDNA were sequenced in G. dimorpha: cytochrome oxidase subunit I (460 bp), cytochrome oxidase subunit II (446 bp), cytochrome b (308 bp), NADH dehydrogenase 3 (585 bp), NADH dehydrogenase 4 (ND4, 835 bp), and 16S rRNA (1300 bp). These sequences were compared with those of G. molesta and C. sasakii in order to develop PCR–RFLP and diagnostic primers. ND4 locus was selected to be used for developing a PCR–RFLP marker. ND4-Swa I digests showed two bands for G. dimorpha, one band for G. molesta, and three bands for C. sasakii. On the other hand, species-specific diagnostic PCR primers were developed using ND4 locus. These markers were then applied to diagnose larvae infesting apples to determine species-specific fruit damage patterns, in which G. dimorpha, G. molesta, and C. sasakii showed different feeding behaviors in terms of their main feeding sites in apple fruits.     

Male and female Popillia quadriguttata (Fabricius) and Protaetia brevitarsis (Lewis) (Coleoptera: Scarabaeidae) response to Japanese beetle floral and pheromone lures

Popillia quadriguttata (Fabricius), and Protaetia brevitarsis (Lewis) adults were captured with Japanese beetle, Popillia japonica Newman, sex attractant and floral lures at Changchun, China during July–August 2012. The floral lure (phenethyl propionate:eugenol:geraniol, 3:7:3) was attractive to male and female P. quadriguttata (AV: 1.2 ± 0.9; 1.1 ± 0.3; total: 2.3 ± 0.8), and was similar in attraction to the combination of the sex attractant (SA) [(R, Z)-5-(1-decenyl) dihydro-2(3H)-furanone] plus the floral lure for male (1.60 ± 0.2), female (1.30 ± 1.1) and total captures (2.9 ± 3.0). However, the SA alone captured only males in much higher numbers than when combined with the floral lure (10.0 ± 6.4). In a separate earlier test, the greatest number of P. quadriguttata males (12.5 ± 3.0), female (12.2 ± 1.5) and total captures (24.7 ± 2.5) was in yellow, laboratory-made, bottle traps. The floral lure also attracted female Pro. brevitarsis (10.0 ± 3.4), while the SA attracted only few male beetles (1.0 ± 0.2). The combination SA + floral lure captured similar females (11.0 ± 2.0) and total (14.2 ± 2.2) Pro. brevitarsis as the floral lure alone. Two butterflies, Colias erate poliographus (Motschulsky) and Pieris rapae (Linnaeus), were also attracted to the floral lure. These studies indicate a potential for replacing pesticides by using the Japanese beetle lures for monitoring and control of several insects in China, and that they would be useful in monitoring and eradication of two potential scarab pests, P. quadriguttata and Pro. brevitaris, in the United States and Europe.     

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.     

Mating disruption of the carpenter moth,Cossus insularis (Staudinger) (Lepidoptera: Cossidae) with synthetic sex pheromone in Japanese pear orchards

Mating disruption of the carpenter moth, Cossus insularis Staudinger (Lepidoptera: Cossidae), with a synthetic version of its sex pheromone, a mixture of (E)-3-tetradecenyl acetate and (Z)-3-tetradecenyl acetate, was tested for three successive years in Japanese pear (Pyrus pyrifolia var. culta) orchards. Pheromone trap catches, percentage mating of tethered females, and tree damage were measured in both the pheromone-treated and untreated control orchards. The attraction of male adults to pheromone traps was completely disrupted, and the mating of the tethered females was completely inhibited by the treatment of synthetic pheromones. The percentage of damaged trees in the pheromone-treated orchard decreased over the course of the experiment, while the damage percentage did not decrease in the untreated orchard. These results show that mating disruption with the synthetic sex pheromone is promising for the reduction of damage caused by C. insularis in apple and Japanese pear orchards.     

Traps and Baits for Luring <Emphasis Type="Italic">Grapholita molesta</Emphasis> (Busck) Adults in Mating Disruption-Treated Apple Orchards

Grapholita molesta (Busck) is one of the main pests in apple crops in Brazil, where it is controlled by mating disruption (MD) with the use of the synthetic sex pheromone. However, sex-pheromone-based monitoring is not effective in MD-treated areas and may result in losses in production. This work has defined a trap model and a bait for luring G. molesta adults in MD apple orchards. The experiments were conducted in commercial apple orchards located in São Joaquim, SC, Brazil. Three trap models—McPhail, Pot, and Ajar—and three baits—grape juice (25%) (GJ), sugarcane molasses (25%) (SM), and a solution containing brown sugar (8.69%) and terpinyl acetate (0.05%) (TAS)—were assessed for luring G. molesta adults in areas subjected to the mating disruption. The assessments were performed weekly by collecting the insects caught in the traps. In addition, time needed to replace traps was also assessed, as well as the selectivity of the trap/bait set. In the laboratory, G. molesta adults were sexed, and the females were dissected to confirm reproductive status. We discuss our results and sugarcane molasses (25%) captured the least number of G. molesta adults regardless of the tested traps. The Ajar/TAS, Pot/TAS, and McPhail/GJ captured the largest number of G. molesta adults. The Ajar/TAS was the most selective and easier to handle. TAS was efficient in catching G. molesta until 14 days after preparation of the solution. Ajar/TAS has potential to be used in the monitoring of G. molesta in apple orchards.     

Crystal structure of the pheromone Er-13 from the ciliate Euplotes raikovi,with implications for a protein–protein association model in pheromone/receptor interactions

In the ciliate Euplotes raikovi, water-borne protein pheromones promote the vegetative cell growth and mating by competitively binding as autocrine and heterologous signals to putative cell receptors represented by membrane-bound pheromone isoforms. A previously determined crystal structure of pheromone Er-1 supported a pheromone/receptor binding model in which strong protein–protein interactions result from the cooperative utilization of two distinct types of contact interfaces that arrange molecules into linear chains, and these into two-dimensional layers. We have now determined the crystal structure of a new pheromone, Er-13, isolated from cultures that are strongly mating reactive with cultures source of pheromone Er-1. The comparison between the Er-1 and Er-13 crystal structures reinforces the fundamental of the cooperative model of pheromone/receptor binding, in that the molecules arrange into linear chains taking a rigorously alternate opposite orientation reflecting the presumed mutual orientation of pheromone and receptor molecules on the cell surface. In addition, the comparison provides two new lines of evidence for a univocal rationalization of observations on the different behaviour between the autocrine and heterologous pheromone/receptor complexes. (i) In the Er-13 crystal, chains do not form layers which thus appear to be an over-structure unique to the Er-1 crystal, not essential for the pheromone signalling mechanisms. (ii) In both crystal structures, the intra-chain interfaces are equally derived from burying amino-acid side-chains mostly residing on helix-3 of the three-helical pheromone fold. This helix is thus identified as the key structural motif underlying the pheromone activity, in line with its tight intra- and interspecific structural conservation.     

Electroantennogram and field responses of Korean population of the rice leaf folder,Cnaphalocrocis medinalis (Lepidoptera: Crambidae), to sex attractant candidates

A series of studies was conducted to determine the optimum sex attractant for monitoring the rice leaf folder, Cnaphalocrocis medinalis, in Korea, based on the previously reported pheromone composition in this species. (Z)-13-Octadecenal (Z13-18:Al) was most active in electroantennogram (EAG) and field tests. (Z)-11-Hexadecenal (Z11-16:Al), (Z)-11-octadecenal (Z11-18:Al), (Z)-11-hexadecenyl acetate (Z11-16:Ac), (Z)-13-octadecenyl acetate (Z13-18:Ac) and (Z)-13-octadecenol (Z13-18:OH) individually elicited significant EAG responses, but were not individually attractive in field trials. (Z)-11-Octadecenol (Z11-18:OH) alone was inactive in both EAG and field tests. The addition of Z11-18:OH and Z13-18:OH to the binary mixture of Z11-18:Al and Z13-18:Al, as the previously reported composition of the Japanese blend, significantly increased the trap catches of males in field trials. In contrast, the Philippine and Indian blends were not attractive to this species. Interestingly, when Z13-18:Ac alone was added to the binary mixture of Z11-18:Al and Z13-18:Al, the trap catch number was the same as that of the Japanese blend. The present study indicates that the four-component blend (Z11-18:Al/Z13-18:Al/Z11-18:OH/Z13-18:OH = 11/100/24/36) and the three-component blend (Z11-18:Al/Z13-18:Al/Z13-18:Ac = 11/100/11) can be used as sex attractants for monitoring the Korean populations of C. medinalis.     

Seasonal monitoring of Drosophila suzukii (Diptera: Drosophilidae) in a mixed fruit production system

Drosophila suzukii Matsumura (Diptera: Drosophilidae), an invasive pest native to Southeast Asia, is now reported throughout North America and Europe. We used traps baited with apple cider vinegar to monitor D. suzukii adult presence in multiple crops and associated fruiting plants at the Wolfskill USDA Germplasm Repository in Winters, CA, USA from 2011 to 2013. Traps were placed in small (~ 160 m × 40 m on average) almond, apricot, cherry, fig, grape, mulberry, peach, persimmon, plum, and pomegranate deciduous fruit orchard blocks as well as a citrus block and evergreen trees located near a house at the repository. D. suzukii was present in all blocks with the greatest monthly deciduous fruit captures in the cherry and fig blocks. Few D. suzukii were captured in almond, apricot, pomegranate and grape blocks. Deciduous fruit blocks had two distinct periods of trap capture: spring through midsummer and again in fall. Most deciduous fruit blocks had low trap captures during the hottest summer months (August to September) and the coldest winter months (December to April). However, from late December through mid-January, high trap captures were associated with the citrus and house sites. This study provides seasonal trapping data of D. suzukii adults in an unsprayed multi-crop mosaic, and may serve as a model of adult capture patterns across smaller mixed-crop commercial orchards and associated urban landscapes.     

Attraction of Gymnosoma rotundatum (Diptera: Tachinidae) to different amounts of Plautia stali (Hemiptera: Pentatomidae) aggregation pheromone and the effect of different pheromone dispensers

The attractiveness of different amounts of the synthetic aggregation pheromone, methyl (E,E,Z)-2,4,6-decatrienoate, of the brown-winged stink bug, Plautia stali (Hemiptera: Pentatomidae) was tested on its parasitoid, Gymnosoma rotundatum (Diptera: Tachinidae), using different types of dispensers in the field. Both sexes of G. rotundatum were attracted to the aggregation pheromone. Pheromones in rubber septum and poly-tube dispensers attracted significantly more G. rotundatum than those in PE-vial dispensers. There were no differences in the attraction of females or males when using 7 to 60 mg pheromone. However, the trap baited with 50 mg pheromone attracted significantly more G. rotundatum of both sexes than the control trap. Further research is necessary to develop an effective pheromone trap that can attract and kill P. stali and can attract G. rotundatum to increase parasitism of the host stink bugs in the field.     

Acetic acid lure placement within traps affects moth catches of codling moth (Lepidoptera: Tortricidae)

Previous studies have shown that the addition of an acetic acid colure (AA) to traps baited with pear ester, (E,Z)‐2,4‐ethyl‐decadienoate, and codlemone, (E,E)‐8,10‐dodecadien‐1‐ol, the sex pheromone (PH) of codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), (Combo lure) can significantly increase moth catches. A commercial AA colure was developed to be used with the Combo lure using a specialized cardboard lure holder. However, research in 2011 suggested that the addition of the AA colure placed in the holder was reducing moth catches. Studies were subsequently conducted in both North America and South America to examine the factors affecting these unexpected results. Hanging the AA colure from the inside top of the delta trap was found to be a primary factor reducing moth catches of male but not female codling moth. Significantly, more males were caught if the AA colure was placed on the sticky liner of the trap than in the holder. Laboratory and field studies found that this negative effect on moth catches lessens over time with aged AA colures that had lower emission rates. The position of the holder in the trap (upwind or downwind) relative to the direction where moths approached was not a significant factor affecting moth catch with the AA colure. However, the spacing of the lures on the holder was an important factor with significantly higher male catches with lures 5.5 cm apart and the AA lure above the Combo lure than with lures 1.5 cm apart and the Combo lure above the AA lure. Similarly, pinning the Combo lure to the roof of the trap was more effective than the use of the holder with the AA lure on the liner. Standardization of lure placement will be important to fully utilize the use of bisexual, multilure monitoring systems for codling moth and likely for other pests.