Olfactory Receptor Neurons for Plant Volatiles and Pheromone Compounds in the Lucerne Weevil, Sitona discoideus.

Antennal olfactory receptor neurons (ORNs) for pheromone-related and plant volatile compounds were identified and characterized in the lucerne weevil, Sitona discoideus (Gyllenhal), using the single sensillum recording technique. Our study using five pheromone-related compounds and 42 plant volatile compounds indicates that S. discoideus have highly specialized ORNs for pheromone and plant volatile compounds. Different groups of ORNs present in both males and females of S. discoideus were highly sensitive to 4-methylheptane-3,5-dione (diketone) and four isomers (RR, RS, SR and SS) of 5-hydroxy-4-methylheptan-3-one, respectively. Our results also indicate that male S. discoideus, using the sensory input from antennal ORNs, can distinguish both diketone and the RR-isomer from others, and RS- and SS-isomers from others, although it was unclear if they can distinguish between RS-isomer and SS-isomer, or between diketone and the SR-isomer. It also appeared that female S. discoideus could distinguish between RS-isomer and SS-isomers. The antennae of S. discoideus thus contain sex-specific sets of ORNs for host- and non-host plant volatile compounds. Both sexes of S. discoideus have highly sensitive and selective ORNs for some green-leaf volatiles, such as (Z)-3-hexenol and (E)-2-hexenal. In contrast, male antennae of S. discoideus house three distinct groups of ORNs specialized for myrcene and (E)-ß-ocimene, 2-phenylethanol, and phenylacetaldehyde, respectively, whereas female antennae contain three groups of ORNs specialized for (±)-linalool and (±)-α-terpineol, myrcene and (E)-ß-ocimene, (±)-1-octen-3-ol, and 3-octanone. Our results suggest that S. discoideus use a multi-component pheromone communication system, and a sex-specific set of ORNs with a narrow range of response spectra for host-plant location.

Will growing invasive arthropod biodiversity outpace our ability for eradication?

The Global Eradication Database documents 811 eradication attempts against invasive arthropods since 1890, in 104 countries. Eradication programs show a greater than exponential increase in the number of programs started in recent decades. In addition, there is a trend of a rapidly diversifying burden of the most severe threats. The species richness showed a three-fold increase in number of species under eradication in the last 50 yr, and all taxonomic levels rose dramatically. The increase in number of eradication programs shows that current management measures for constraining the spread of invasive species are inadequate. A similar surge in the number of governments trying to prevent the establishment of new pests has occurred. Increased biodiversity of arthropod eradication targets includes new pest groups with fewer tools developed for management. We argue that a rapid increase in biodiversity of invasive and economically or environmentally damaging organisms represents a substantial and underestimated challenge for managers wanting to prevent their establishment, requiring a shift in research focus to accelerate delimitation and suppression options with less reliance on insecticides.

Associative Learning of Food Odor by Social Wasps in a Natural Ecosystem.

The ability of insects to associate olfactory cues with food from their environment has been well documented with various insect orders. However, these studies were based on prior training of insects to associate odors with food sources in the laboratory or in the field with almost no evidence for the development of this phenomenon in natural ecosystems. In New Zealand's ancient Fuscospora spp. or beech forests, invasive Vespula social wasps were attracted to odor from honeydew (benzaldehyde and n-octanol) but did not respond to a known wasp attractant (isobutanol and acetic acid). On the other hand, wasps in a rural/suburban area in New Zealand did not respond to honeydew odor but responded instead to the known wasp attractant. Similarly, social wasps in Hungary did not respond to honeydew odor, but responded to the known wasp attractant. DNA sequences of Vespula vulgaris from the two locations in New Zealand were 100% identical. Similarly, DNA sequences of V. germanica from the two locations in New Zealand were 100% identical, indicating little or no intra-specific variation. On the other hand, DNA sequences of V. vulgaris and V. germanica from New Zealand were 99.56 and 99.78% matches with V. vulgaris and V. germanica samples from Hungary, respectively. Electroantennogram (EAG) response profiles of wasps from the three locations to benzaldehyde, isobutanol, acetic acid, n-octanol and heptyl butyrate were similar. The high similarity in DNA sequences and EAG profiles, with only a behavioral difference in the response to odor sources, suggests that social wasps in New Zealand's beech forest have naturally developed associative learning for the odor of the carbohydrate-rich honeydew. This is the first study to provide conclusive evidence of the occurrence and the development of associative learning of food odor by social insects in a natural ecosystem free of human interference. The ability of social wasps to naturally develop associative learning of food odor might in part explain why they are extremely successful invaders of new ecosystems, especially those with rich honeydew resources. The finding of our study will have significant implications for the use of attractants in wasp monitoring and control in different habitats.

The importance of key floral bioactive compounds to honey bees for the detection and attraction of hybrid vegetable crops and increased seed yield.

BACKGROUND: Crop breeding programmes generally select for traits for improved yield and human consumption preferences. Yet, they often overlook one fundamental trait essential for insect-pollinated crops: pollinator attraction. This is even more critical for hybrid plants that rely on cross-pollination between the male-fertile line and the male-sterile line to set seeds. This study investigated the role of floral odours for honey bee pollination that could explain the poor seed yield in hybrid crops. RESULTS: The key floral bioactive compounds that honey bees detect were identified for three vegetable hybrid crops. It was found that 30% of the variation in bioactive compound quantities was explained by variety. Differences in quantities of the bioactive compounds triggered different degrees of olfactory response and were also associated with varied appetitive response. Correlating the abundance of each bioactive compound with seed yield, it was found that aldehydes such as nonanal and decanal can have a strong negative influence on seed yield with increasing quantity. CONCLUSION: Using these methodologies to identify relevant bioactive compounds associated with honey bee pollination, plant breeding programmes should also consider selecting for floral traits attractive to honey bees to improve crop pollination for enhanced seed yield. © 2018 Society of Chemical Industry.

Eradication of Invading Insect Populations: From Concepts to Applications.

Eradication is the deliberate elimination of a species from an area. Given that international quarantine measures can never be 100% effective, surveillance for newly arrived populations of nonnative species coupled with their eradication represents an important strategy for excluding potentially damaging insect species. Historically, eradication efforts have not always been successful and have sometimes been met with public opposition. But new developments in our understanding of the dynamics of low-density populations, the availability of highly effective treatment tactics, and bioeconomic analyses of eradication strategies offer new opportunities for developing more effective surveillance and eradication programs. A key component that connects these new developments is the harnessing of Allee effects, which naturally promote localized species extinction. Here we review these developments and suggest how research might enhance eradication strategies.

Invasive Vespula Wasps Utilize Kairomones to Exploit Honeydew Produced by Sooty Scale Insects, Ultracoelostoma.

Vespula wasps are widely distributed invasive alien species that are able to reach high population densities in the 1.2 M ha of beech forests (Fuscospora spp.) of New Zealand's South Island. These endemic temperate forests have an abundance of carbohydrate-rich honeydew produced by native scale insects (Ultracoelostoma spp.). A characteristic aroma is associated with the honeydew in beech forests, which we hypothesized is the signal used by wasps to harvest the vast resources previously exploited by birds and other insects. Volatile collections were taken of black beech tree trunks with honeydew and sooty mold present, and analyzed with a gas chromatograph-mass spectrometer. Eleven compounds (benzaldehyde, benzyl alcohol, 2-phenylethyl acetate, 2-phenylethanol, phenylacetaldehyde, methyl 2-phenylacetate, ethyl 2-phenylacetate, methyl salicylate, n-octanol, octan-3-ol, and 1-octen-3-ol) were positively identified from the headspace, and were shown to elicit an electrophysiological response from Vespula vulgaris worker antennae by using electroantennography (EAG). Field trials with delta traps individually baited with these compounds confirmed wasp attraction to 8 of the 11 compounds tested, with 2-phenylethyl acetate, methyl salicylate, and octan-3-ol capturing the same numbers of wasps as the control. In later trials, attraction to a 1:1 blend of benzaldehyde and n-octanol was significantly higher (45%) than to any other treatment. Many of the chemicals identified are known to be associated with fermenting sugars, or with fungal aroma. Benzaldehyde and n-octanol are common compounds produced by many different species in nature. The ability to respond to generic signals emanating from sugar resources is likely to contribute to the success of V. vulgaris as an invasive species.

Influence of the pathogen Candidatus Liberibacter solanacearum on tomato host plant volatiles and psyllid vector settlement.

Candidatus Liberibacter solanacearum (CLso) is an unculturable bacterium vectored by the tomato potato psyllid (TPP) Bactericera cockerelli and has been associated with Zebra chip disease in potato and with other economically relevant symptoms observed in solanaceous crops. By altering their host and vector's biological system, pathogens are able to induce changes that benefit them by increasing their transmission rate. Understanding these changes can enable better targeting of mechanisms to control pathogen outbreaks. Here, we explored how the CLso infectious status affects the volatile organic compounds (VOCs) of the tomato plant, and whether the CLso infectious status of TPP influences host plant settlement. These chemical and behavioral changes can ultimately affect the rate of encounter between the host and the vector. Results from headspace volatile collection of tomato plants showed that CLso infected tomato plants emitted a qualitatively and quantitatively different blend of VOCs compared to sham-infected plants. By a factorial experiment, we showed that CLso negative (CLso-) TPP preferred to settle 70 % more often on infected tomato plants, while CLso positive (CLso+) TPP were found 68 % more often on sham-infected tomato plants. These results provide new evidence in favor of both host and vector manipulation by CLso.

Apple volatiles synergize the response of codling moth to pear ester.

Codling moth, Cydia pomonella L. (Lepidoptera: Tortricidae), is a major cosmopolitan pest of apple and other pome fruits. Ethyl (E,Z)-2,4-decadienoate (pear ester) has been identified as a host-derived kairomone for female and male codling moths. However, pear ester has not performed similarly in different fruit production areas in terms of the relative magnitude of moth catch, especially the proportion of females caught. Our work was undertaken to identify host volatiles from apples, and to investigate whether these volatiles can be used to enhance the efficacy of host kairomone pear ester for monitoring female and male codling moths. Volatiles from immature apple trees were collected in the field using dynamic headspace sampling during the active period of codling moth flight. Using gas chromatography-electroantennogram detector (GC/EAD) analysis, six compounds elicited responses from antennae of females. These compounds were identified by GC/mass spectrometry (MS) and comparisons to authentic standards as nonanal, (E)-4,8-dimethyl-1,3,7-nonatriene, methyl salicylate, decanal, (Z,E)-α-farnesene, and (E,E)-α-farnesene. When the EAD-active compounds were tested individually in the field, no codling moths were caught except for a single male with decanal. However, addition of (E)-4,8-dimethyl-1,3,7-nonatriene, methyl salicylate, decanal, or (E,E)-α-farnesene to pear ester in a binary mixture enhanced the efficacy of pear ester for attracting female codling moths compared to pear ester alone. Addition of the 6-component blend to the pear ester resulted in a significant increase in the number of males attracted, and enhanced the females captured compared to pear ester alone; the number of males and females caught was similar to that with the pear ester plus acetic acid combination lure. Our results demonstrate that it is possible to synergize the response of codling moth to host kairomone by using other host volatiles. The new apple-pear ester host kairomone blend should be helpful for monitoring female codling moth, and may provide the basis for further improvement of codling moth kairomone.

Irradiation of adult Epiphyas postvittana (Lepidoptera: Tortricidae): egg sterility in parental and F1 generations.

Adult Epiphyas postvittana Walker were irradiated using a Cobalt 60 source to determine the dose needed to achieve complete egg sterility of mated female moths, and egg sterility of female moths mated to F1 generation males. Adult male and female E. postvittana were irradiated at 100, 200, 250, and 300 Gy and their fertility (when crossed with normal moths) was compared with nonirradiated moths. Viable progeny (determined by egg hatch) were found at doses of 100 and 200 Gy, but very little at 250 and 300 Gy. In particular, there was no survival of female progeny into the F1 generation. Males irradiated at 250 and 300 Gy had very low egg eclosion rates (2.25 and 1.86% at 250 and 300 Gy, respectively) when mated with normal females. The F2 generation from those male progeny had a mean percent hatched of < 1.02%. Based on our results, a dose of 250-300 Gy is recommended for irradiation of E. postvittana adults used for sterile insect technique (SIT) if sterility of parental moths is the desired outcome. Our data also suggests that inclusion of F1 hybrid sterility rather than parental generation sterility into programs using the SIT may allow for doses lower than what we have reported, especially during initial phases of an eradication program where increase fitness of moths might be desirable. Further research is needed to verify the use of F1 hybrid sterility in light brown apple moth SIT programs.

Communication disruption of Epiphyas postvittana (Lepidoptera: Tortricidae) by using two formulations at four point source densities in vineyards.

Light brown apple moth [Epiphyas postvittana (Walker)] is now established as an economic and quarantine pest in California, and new technologies are being investigated to increase options for its management. Two new organic formulations for mating disruption, SPLAT LBAM HD-O and organic Hercon Biotie (biodegradable) were field tested at four point source densities (25, 72, 322, and 500/ha) and compared with the standard Isomate LBAM Plus (500/ha, as a positive control) and an untreated (negative) control. Assessment involved trapping using synthetic lures and virgin females. In total, 175,776 male light brown apple moths were caught to both the caged females and synthetic lures, from 10 February to 19 May 2011. The light brown apple moth catch dramatically decreased from baseline measurements after the treatments were applied, with the highest density treatments reducing catch to below 10% of the catch in the untreated controls within the first week (> 90% disruption). In synthetic lure traps, the SPLAT and Biotie treatment performed similarly well over all rates (P = 0.317 for posttreatment percentage communication disruption), but SPLAT performed better at disrupting virgin female traps (P = 0.045). There was a significant increase in disruption with an increasing number of points/ha (P < 0.001). Disruption of communication was similar for all three technologies (SPLAT, Biotie and Isomate) at 500 points/ha for both types of trap (P > 0.74). Disruption of this species in vineyards is thus highly feasible.

Identification of herbivore-induced plant volatiles from selected Rubus species fed upon by raspberry bud moth (Heterocrossa rubophaga) larvae.

Heterocrossa rubophaga (raspberry bud moth) feed on a range of Rubus species, including commercial berryfruit crops where they are a pest. This study aimed to characterize the responses of native and non-native Rubus species to feeding by raspberry bud moth larvae. In a laboratory environment, in situ headspace volatiles of three Rubus species were collected from healthy plants and those fed upon by raspberry bud moth. Rubus cissoides (bush lawyer), the native host of raspberry bud moth, gave a limited response to larval feeding with green leaf volatiles (GLVs) representing the only new headspace constituents of the infested plants. The non-native hosts, Rubus ursinus var. loganobaccus cv Boysenberry (Boysenberry), and Rubus fruticosus (blackberry), gave strong responses to raspberry bud moth herbivory, releasing a number of unique nitrogenous compounds in conjunction with the GLVs. The nitrogenous compounds were identified as 2-methylbutanenitrile, (Z)- and (E)- 2-methylbutanal O-methyloxime, benzyl nitrile, (Z)- and (E)- phenylacetaldehyde O-methyloxime and indole. The four methyloximes and 2-methylbutanenitrile were confirmed by synthesis. Field collected phenology data showed that raspberry bud moth were active year round on both bush lawyer and blackberry.

Radiation biology and inherited sterility of light brown apple moth (Lepidoptera: Tortricidae): developing a sterile insect release program.

The radiation biology of two geographically isolated populations of the light brown apple moth [Epiphyas postvittana (Walker)] was studied in Australia and New Zealand as an initiation of a SIT/F1 sterility program. Pharate and < or = 2 d pre-emergence pupae were exposed to increasing radiation doses up to a maximum dose of 300 Gy. Fertility and other life history parameters were measured in emerging adults (parental) and their progeny (F1-F3 adults). Parental fecundity was significantly affected by increasing irradiation dose in pharate pupae only. For both populations, parental egg fertility declined with increasing radiation. This was most pronounced for the irradiated parental females whose fertility declined at a higher rate than of irradiated males. At 250 Gy, females < or = 2 d preemergence pupae produced few larvae and no adults at F1. No larvae hatched from 250 Gy-irradiated female pharate pupae. At 300 Gy, males still had residual fertility of 2-5.5%, with pharate pupae being the more radio-sensitive. Radiation-induced deleterious inherited effects in offspring from irradiated males were expressed as increased developmental time in F1 larvae, a reduction in percent F1 female survival, decreased adult emergence and increased cumulative mortality over subsequent generations. Males irradiated at > or = 150 Gy produced few but highly sterile offspring at F1 and mortality was > 99% by F2 egg.

Comparative fitness of irradiated light brown apple moths (Lepidoptera: Tortricidae) in a wind tunnel, hedgerow, and vineyard.

Light brown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae), is the target of the sterile insect technique, but reduced moth fitness from irradiation lowers the effective overflooding ratio of sterile to wild moths. New measures of insect quality are being sought to improve field performance of irradiated insects, thus improving the cost effectiveness of this technique. Male pupae were irradiated at intervals between 0 and 300 Gy, and adult flight success was assessed in a wind tunnel equipped with flight track recording software. A dose response was evident with reduced successful search behaviors at higher irradiation doses. Irradiation at 250 Gy reduced arrival success to 49% of untreated controls, during 2-min assays. Mark-release-recapture of males irradiated at 250 Gy indicated reduced male moth recapture in hedgerows (75% of control values of 7.22% +/- 1.20 [SEM] males recaptured) and in vineyards (78% of control values 10.5% +/- 1.66% [SEM] recaptured). Males dispersed similar distances in both habitats, and overflooding ratios dropped off rapidly from the release point in both landscapes. Transects of traps with central releases proved to be an efficient method for measuring the quality of released males. Relative field performance of moths was greater than suggested by wind tunnel performance, which could be due to time differences between the two assays, two-minute wind tunnel tests compared with days in the field treatments. Release strategies involving ground releases should consider the effect of limited postrelease dispersal. Aerial release could solve this problem and warrants investigation.

Synthesis and Electrophysiological Testing of Carbonyl Pheromone Analogues for Carposinid Moths.

Sex pheromone analogues were synthesized and tested on two pest carposinid moth species: the guava moth, Coscinoptycha improbana, and the raspberry bud moth, Heterocrossa rubophaga. The pheromone analogues used for the electroantennogram testing included (Z)-11-methylenenonadec-7-ene, (Z)-nonadec-12-en-9-amine, (Z)-11-methoxynonadec-7-ene, (Z)-1-(octylsulfinyl)-dec-3-ene, and (Z)-nonadec-12-en-9-ol. An imine analogue, N-((Z)-nonadec-12-en-9-ylidene)cyclopropanamine, was also synthesized but was too unstable for testing with the moths. None of the analogue compounds elicited significant responses from the male moth antennae.

Liquid Baits with Oenococcus oeni Increase Captures of Drosophila suzukii.

The spotted-wing drosophila (SWD), Drosophila suzukii Matsumura (Diptera: Drosophilidae), native to Eastern Asia, is an invasive alien species in Europe and the Americas, where it is a severe pest of horticultural crops, including soft fruits and wine grapes. The conventional approach to controlling infestations of SWD involves the use of insecticides, but the frequency of application for population management is undesirable. Consequently, alternative strategies are urgently needed. Effective and improved trapping is important as an early risk detection tool. This study aimed to improve Droskidrink® (DD), a commercially available attractant for SWD. We focused on the chemical and behavioral effects of adding the bacterium Oenococcus oeni (Garvie) to DD and used a new trap design to enhance the effects of attractive lures. We demonstrate that microbial volatile compounds produced by O. oeni are responsible for the increase in the attractiveness of the bait and could be later utilized for the development of a better trapping system. Our results showed that the attractiveness of DD was increased up to two-fold by the addition of commercially available O. oeni when combined with an innovative trap design. The new trap-bait combination increased the number of male and especially female catches at low population densities.

Trail pheromone disruption of red imported fire ant.

The fire ant, Solenopsis invicta (Hymenoptera: Formicidae), is considered one of the most aggressive and invasive species in the world. Toxic bait systems are used widely for control, but they also affect non-target ant species and cannot be used in sensitive ecosystems such as organic farms and national parks. The fire ant uses recruitment pheromones to organize the retrieval of large food resources back to the colony, with Z,E-alpha-farnesene responsible for the orientation of workers along trails. We prepared Z,E-alpha-farnesene, (91% purity) from extracted E,E-alpha-farnesene and demonstrated disruption of worker trail orientation after presentation of an oversupply of this compound from filter paper point sources (30 microg). Trails were established between queen-right colony cells and food sources in plastic tubs. Trail-following behavior was recorded by overhead webcam, and ants were digitized before and after presentation of the treatment, using two software approaches. The linear regression statistic, r(2) was calculated. Ants initially showed high linear trail integrity (r(2) = 0.75). Within seconds of presentation of the Z,E-alpha-farnesene treatment, the trailing ants showed little or no further evidence of trail following behavior in the vicinity of the pheromone source. These results show that trailing fire ants become disorientated in the presence of large amounts of Z,E-alpha-farnesene. Disrupting fire ant recruitment to resources may have a negative effect on colony size or other effects yet to be determined. This phenomenon was demonstrated recently for the Argentine ant, where trails were disrupted for two weeks by using their formulated trail pheromone, Z-9-hexadecenal. Further research is needed to establish the long term effects and control potential for trail disruption in S. invicta.

Fatty acid-amino acid conjugates diversification in lepidopteran caterpillars.

Fatty acid amino acid conjugates (FACs) have been found in noctuid as well as sphingid caterpillar oral secretions; in particular, volicitin [N-(17-hydroxylinolenoyl)-L-glutamine] and its biochemical precursor, N-linolenoyl-L-glutamine, are known elicitors of induced volatile emissions in corn plants. These induced volatiles, in turn, attract natural enemies of the caterpillars. In a previous study, we showed that N-linolenoyl-L-glutamine in larval Spodoptera litura plays an important role in nitrogen assimilation which might be an explanation for caterpillars synthesizing FACs despite an increased risk of attracting natural enemies. However, the presence of FACs in lepidopteran species outside these families of agricultural interest is not well known. We conducted FAC screening of 29 lepidopteran species, and found them in 19 of these species. Thus, FACs are commonly synthesized through a broad range of lepidopteran caterpillars. Since all FAC-containing species had N-linolenoyl-L-glutamine and/or N-linoleoyl-L-glutamine in common, and the evolutionarily earliest species among them had only these two FACs, these glutamine conjugates might be the evolutionarily older FACs. Furthermore, some species had glutamic acid conjugates, and some had hydroxylated FACs. Comparing the diversity of FACs with lepidopteran phylogeny indicates that glutamic acid conjugates can be synthesized by relatively primitive species, while hydroxylation of fatty acids is limited mostly to larger and more developed macrolepidopteran species.

Selection of key floral scent compounds from fruit and vegetable crops by honey bees depends on sensory capacity and experience.

Flowers have complex odours often comprising hundreds of volatile compounds. Floral scents are species-specific, and vary also among populations, varieties, sexes or lines, as well as with phenology. Honey bees, Apis mellifera, generally associate only a few key compounds among the complex floral scent with the food reward which guides their foraging choices. How these key compounds are selected remains partially unexplained, despite their crucial role in influencing foraging. Using electrophysiological techniques and behavioural assays, we identified the key bioactive compounds that bees detected with their antennae and that were associated with appetitive responses from four fruit crops and three vegetable crops. Three quantities of identified key volatile compounds were assayed with the two methods in each of four different seasons with experienced foragers. Whether the selection of these key compounds is determined by the sensory capability of the bee or influenced by its foraging experience was assessed by comparing experienced and naïve bees. Our results showed that experienced foragers were electrophysiologically-sensitive to a specific set of key compounds for each crop, independent of variation in quantity among several varieties. Experienced foragers responded to these compounds in all seasons, with increased electrophysiological amplitude with increasing quantities. Behavioural appetitive responses varied amongst compounds and seasons, revealing preferences based on associative learning. Naïve bees that were exposed to compounds and subsequently learned them, tended to be overall more sensitive. We discuss our results based on the identity of each bioactive compound and their presence in nature. Preferences for specific floral compounds based on sensory biases exist and associative learning may reinforce behavioural attraction depending on foraging experience in each season.

Synthesis and Biological Testing of Ester Pheromone Analogues for Two Fruitworm Moths (Carposinidae).

A range of ester pheromone analogues for carposinid moths were synthesized and evaluated for biological activity. The analogues aimed to take advantage of the structural commonality of (7Z)-alken-11-ones found in this family. Analogues were tested on two pest species: Heterocrossa rubophaga and Coscinoptycha improbana. Two of the analogues, (2Z)-nonenyl nonanoate and (4Z)-heptyl undecenoate, elicited significant electroantennogram responses. Only (4Z)-heptyl undecenoate gave consistent responses with both moth species in single sensillum recording. Field trapping trials were conducted with these two analogues both individually and in combination with the pheromone of each of the two moth species. No attraction was observed to either of the analogues alone, by either moth species. However, when (4Z)-heptyl undecenoate was coupled with the pheromone, it produced a strong inhibitory effect in H. rubophaga, reducing male moth trap catch by over 95%. No inhibitory effect on male moth trap catch was observed in C. improbana.

Leafroller-induced phenylacetonitrile and acetic acid attract adult Lobesia botrana in European vineyards.

We recently identified unique caterpillar-induced plant volatile compounds emitted from apple leaves infested with the larvae of various leafroller species. In subsequent field tests, binary blends of phenylacetonitrile+acetic acid and 2-phenylethanol+acetic acid were found to be attractive to a range of tortricid leafroller species (Tortricidae: Tortricinae) in both the Southern and Northern Hemispheres. In this work, the caterpillar-induced plant volatiles from the apple-leafroller system were tested in two vineyards in Spain and Hungary for their attractiveness to the grape frugivore Lobesia botrana (Tortricidae: Olethreutinae). As seen for Tortricinae species, a binary blend of phenylacetonitrile+acetic acid attracted significantly more male and female L. botrana to traps than acetic acid or blank lures. Traps baited with other caterpillar-induced plant volatile compounds (benzyl alcohol, 2-phenylethanol, indole, and (E)-nerolidol, each as a binary blend with acetic acid) did not catch significantly more moths than traps containing acetic acid alone. The catches of male and female moths support an optimistic future for new products in female tortricid surveillance and control that are based on combinations of kairomone compounds released from larval-damaged foliage.