Mating Disruption as a Suppression Tactic in Programs Targeting Regulated Lepidopteran Pests in US

Exploration of D-limonene as a sex pheromone for males of Bactrocera minax (Diptera: Tephritidae)

BACKGROUND

Bactrocera minax is a devastating pest of citrus fruits. However, there have been no effective control measures before. Few reports on the sex pheromones of B. minax are available.

RESULTS

In this study, nine of the volatile compounds in adult females were identified using headspace solid-phase microextraction (HS-SPME) in combination with gas chromatography-mass spectrometry (GC-MS). Among them, d-limonene, caprolactam, 2-Nitro-1H-imidazole, and creatinine could evoke antennal responses in males. Field bioassays showed that only d-limonene could lure male flies, with a relative lure rate of 78.18% in all tested samples, which was significantly higher than that of paraffin oil control, while all volatile compounds did not have any lure effective to female flies. Moreover, d-limonene was diluted with paraffin oil into differential concentrations, the lure effect on males was better at 100, 500, and 800 μL d-limonene mL-1 than pure d-limonene (1000 μL mL-1 ). The relative male lure rate of d-limonene at 100 μL mL-1 was 85.88%, which was significantly higher than that of food-baits (14.12%) on day 3. However, d-limonene was unattractive to female and male Bactrocera dorsalis and Zeugodacus tau. Further kinetic analysis showed that female adults released d-limonene around 15-day post eclosion. Electroantennography 1 results showed that 500 μL mL-1 d-limonene evoked the strongest responses to antennae of 10- to 25-day-old male flies.

CONCLUSION

Our results indicated that d-limonene could be a sex pheromone from female flies of B. minax, and it could be used as a male-specific sex attractant for B. minax. © 2023 Society of Chemical Industry.

Less is more: Fewer attract-and-kill sites improve the male annihilation technique against Bactrocera dorsalis (Diptera: Tephritidae)

The Male Annihilation Technique (also termed the Male Attraction Technique; "MAT") is often used to eradicate pestiferous tephritid fruit flies, such as Bactrocera dorsalis (Hendel). MAT involves the application of male-specific attractants combined with an insecticide in spots or stations across an area to reduce the male population to such a low level that suppression or eradication is achieved. Currently, implementations of MAT in California and Florida targeting B. dorsalis utilize the male attractant methyl eugenol (ME) accompanied with a toxicant, such as spinosad, mixed into a waxy, inert emulsion STATIC ME (termed here "SPLAT-MAT-ME"). While highly effective against ME-responding species, such applications are expensive owing largely to the high cost of the carrier matrix and labor for application. Until recently the accepted protocol called for the application of approximately 230 SPLAT-MAT-ME spots per km2; however, findings from Hawaii suggest a lower density may be more effective. The present study adopted the methods of that earlier work and estimated kill rates of released B. dorsalis under varying spot densities in areas of California and Florida that have had recent incursions of this invasive species. Specifically, we directly compared trap captures of sterilized marked B. dorsalis males released in different plots under three experimental SPLAT-MAT-ME densities (50, 110, and 230 per km2) in Huntington Beach, CA; Anaheim, CA; and Sarasota-Bradenton, FL. The plots with a density of 110 sites per km2 had a significantly higher recapture proportion than plots with 50 or 230 sites per km2. This result suggests that large amounts of male attractant may reduce the ability of males to locate the source of the odor, thus lowering kill rates and the effectiveness of eradication efforts. Eradication programs would directly benefit from reduced costs and improved eradication effectiveness by reducing the application density of SPLAT-MAT-ME.

Tracking the push towards extinction: combining dispersal and management data to monitor Asian longhorned beetle eradication in the U.S

Introduction

Based on the threat posed by the Asian longhorned beetle (Anoplophora glabripennis Motschulsky), many countries including the United States have adopted policies of eradication. The eradication of infestations that cover hundreds of square kilometers can require multiple visual surveys of millions of individual trees. At these scales, eradication may take several decades and span multiple beetle generations. During this period the infestation of new trees adds spatially-explicit risk to the landscape while surveys and the removal of infested trees reduce it.

Methods

To track dynamic risk on the landscape we have developed the Asian Longhorned Beetle Hazard Management and Monitoring Tool. The geospatial tool combines data documenting; the locations, levels of infestation, and dates of detection of infested trees; the locations, methods, and timing of survey and host removal activities; and a reconstruction of beetle movement within the infested landscape to generate annual spatial estimates of infestation risk based on the combination of beetle dispersal and survey and host removal activities.

Results

The analyses of three eradication programs highlight similar patterns in risk through time with risk peaking at the time infestations are detected and declining as management activities slow beetle spread and reduce risk through surveys. However, the results also highlight differences in risk reduction among the eradication programs associated with differences in beetle dispersal among infestations and the size of the infested landscape, highlighting the importance of applying local information to structure eradication programs.

Discussion

The Asian Longhorned Beetle Hazard Management and Monitoring Tool provides a quantitative repeatable approach to tracking changes in infestation risk using local beetle behavior and management efforts. In addition to this, the tool may provide a structure to optimize eradication efforts by allowing managers to estimate expected risk reduction based on proposed survey and host removal strategies.

Dual effects of entomopathogenic fungi on control of the pest Lobesia botrana and the pathogenic fungus Eutypella microtheca on grapevine

Background

Entomopathogenic fungi (EPF) are the natural enemies of insect pests. Nevertheless, research on the use of EPF for simultaneous prevention of pest and disease agents on the same crop is limited. In this study, we explored the potential dual effects of three strains of the EPF Metarhizium anisopliae on the control of detrimental agents of Vitis vinifera L., including different developmental stages (larvae, pupae, and adult) of the insect pest Lobesia botrana and the phytopathogenic fungus Eutypella microtheca.

Methods

Laboratory pathogenicity trials were performed to examine the effects of the three M. anisopliae strains on the mortality rate of L. botrana. In addition, field trials were conducted to assess the biocontrol potential of one selected M. anisopliae strain on the larval stage of L. botrana. Moreover, inhibitory effects of the three EPF strains on E. microtheca growth were examined in vitro.

Results

All the M. anisopliae strains were highly effective, killing all stages of L. botrana as well as inhibiting the growth of E. microtheca. The in vitro mortality of larvae treated with the strains was over 75%, whereas that of treated pupae and adults was over 85%. The three EPF strains showed similar efficacy against larvae and adult stages; nevertheless, pupal mortality was observed to be strain dependent. Mortality of L. botrana larvae ranged from 64 to 91% at field conditions. Inhibition of E. microtheca growth reached 50% in comparison to the control.

Conclusions

Our study showed that M. anisopliae strains were highly effective in ensuring control of two different detrimental agents of V. vinifera L., providing new evidence to support the dual effects of entomopathogenic fungi.

Organic Control Strategies for Use in IPM of Invertebrate Pests in Apple and Pear Orchards

Growers of organic tree fruit face challenges in controlling some pests more easily suppressed by broad-spectrum insecticides in conventionally managed orchards. In recent decades, there has been a move towards organically growing varieties normally reliant on synthetic chemical pesticides (e.g., Gala), often to meet retailer/consumer demands. This inevitably makes crop protection in organic orchards more challenging, as modern varieties can be less tolerant to pests. In addition, there have been substantial reductions in plant protection product (PPP) approvals, resulting in fewer chemical options available for integrated pest management (IPM)-maintained orchards. Conversely, the organic management of fruit tree pests involves many practices that could be successfully implemented in conventionally grown crops, but which are currently not. These practices could also be more widely used in IPM-maintained orchards, alleviating the reliance on broad-spectrum PPP. In this review, we evaluate organic practices, with a focus on those that could be incorporated into conventional apple and pear production. The topics cover cultural control, biological control, physical and pest modifications. While the pests discussed mainly affect European species, many of the methods could be used to target other global pests for more environmentally sustainable practices.

Towards developing areawide semiochemical-mediated, behaviorally-based integrated pest management programs for stored product insects

With less emphasis on fumigation after harvest, due to the phase-out of methyl bromide and increasing phosphine resistance, diversified postharvest integrated pest management (IPM) programs are needed. Here, we synthesize knowledge on semiochemical-mediated, behaviorally-based tactics, wherein semiochemicals are deployed to manipulate pest behavior to protect commodities. We note that beyond monitoring, commercial use is limited to mating disruption targeting mostly moths. In total, behaviorally-based tactics have been attempted for eight species of stored product insects from two orders and six families. Eighteen challenges were identified that may have prevented robust implementation of semiochemicals for behaviorally-based management in stored products, including direct competition with ubiquitous food cues, and the diverse insect assemblages that colonize food facilities. Further, we discuss the scientific data and methods required to support stakeholder acceptance of semiochemicals at food facilities, including demonstrating that pests are not attracted from the landscape and minimal spillover around pheromones. We sketch a robust areawide behaviorally-based IPM program after harvest, and clarify properties for improving semiochemicals, including incorporating those that are broad spectrum, competitive with food cues, potent at low concentration, and exhibit dose-dependent attraction. The research gaps and testable hypotheses described here will speed developing behaviorally-based tactics at food facilities. © 2021 Society of Chemical Industry.

Latest Developments in Insect Sex Pheromone Research and Its Application in Agricultural Pest Management

Since the first identification of the silkworm moth sex pheromone in 1959, significant research has been reported on identifying and unravelling the sex pheromone mechanisms of hundreds of insect species. In the past two decades, the number of research studies on new insect pheromones, pheromone biosynthesis, mode of action, peripheral olfactory and neural mechanisms, and their practical applications in Integrated Pest Management has increased dramatically. An interdisciplinary approach that uses the advances and new techniques in analytical chemistry, chemical ecology, neurophysiology, genetics, and evolutionary and molecular biology has helped us to better understand the pheromone perception mechanisms and its practical application in agricultural pest management. In this review, we present the most recent developments in pheromone research and its application in the past two decades.

Development of Sterile Insect Technique for Control of the European Grapevine Moth, Lobesia botrana, in Urban Areas of Chile

Simple Summary

The establishment of the European grapevine moth in Chile presented significant production and export concerns for the grape and fruit industries. A national control campaign was launched in response. Infestations in urban areas adjacent to agricultural production areas were a significant challenge for control due to the difficulties in mounting effective measures in residential areas. The Servicio Agrícola y Ganadero launched a program to develop a sterile insect technique (SIT) as a means to provide an environmentally friendly method of control in areas where other control measures were not possible to employ. Here, we report the progress made to develop the SIT response capacity with a production of 75,000 sterile moths per week, as well as the results from a season-long SIT release program in a section of a small city in a grape and fruit production region in central Chile. Because of the high moth population in this area, the release of sterile moths did not reach large enough ratios of sterile to wild moths to achieve effective control, but high moth quality and field performance were observed. Recommendations are provided for further development of SIT and how to integrate its use into an effective area-wide control program.

Abstract

The European grapevine moth, a Palearctic pest, was first detected in the Americas in 2008. Its establishment in Chile presented production and export issues for grapes and other fruits, and a national control campaign was launched. Urban areas next to agricultural production areas were recognized as a challenge for effective control. In 2015, a SIT laboratory was established in Arica, Chile to evaluate its potential for urban control. Progress included the development and evaluation of artificial diets, a mass-rearing of 75,000 moths/week, confirmation of 150 Gy as an operational dose for inherited sterility, and releases of sterile moths in a 25 ha urban area next to fruit production areas. Season-long releases demonstrated that high overflooding ratios were achieved early in the season but decreased with a large increase in the wild moth population. Sterile moth quality was consistently high, and moths were observed living in the field up to 10 days and dispersing up to 800 m. Recommendations for further development of the SIT include conducting cage and field studies to evaluate overflooding ratios and mating competitiveness, measuring of infestation densities in release and no-release areas, and conducting trials to evaluate combining SIT with compatible integrated pest management (IPM) tactics such as fruit stripping and use of mating disruption.

Biorational method for controlling the abundance of Cydia pomonella L. in apple agrocenoses of the Krasnodar region

In the region of Krasnodar Territory, Cydia pomonella L. belongs to the dominant pests of the apple tree, against which 8-10 treatments with insecticides are carried out during the growing season. In world practice, pheromones Shin-Etsu® MD CTT, D and BRIZ® are used in apple agrocenoses for the control of C. pomonella. abstention or reduction of insecticidal treatments leads to a decrease in the pesticide load on the agrocenosis of the garden by a factor of two or more. The objective of our research was to determine the biological pheromones effectiveness in controlling C. pomonella quantity. The test was carried out in two horticultural zones of the Krasnodar Territory, in areas with different numbers of phytophage. The experiment as a result, it was found that in the experimental plots the percentage of damaged fruits in the drop was 1.3-1.5%. Fruit damage wasn’t observed in a removable crop, which corresponds to the results of the standard version, with the use of insecticidal treatments. It was found that the pheromones usage in the Black Sea horticultural zone of the Krasnodar Territory is economically feasible. Сost reduction for the purchase of insecticides amounted to 9089.2 rub/ha, a decrease in pesticide load by 70%.

Synthetic pheromone exposure increases calling and reduces subsequent mating in female Contarinia nasturtii (Diptera: Cecidomyiidae)

BACKGROUND

Pheromone-mediated mating disruption, which uses large amounts of synthetic female pheromones to interrupt insect reproductive behavior, has been successful for managing important agricultural pests. While multiple mechanisms have been discovered explaining how synthetic pheromone treatments prevent males from finding females, it is less clear how unnaturally large doses of synthetic sex pheromone impact the behavior of female insects, particularly nonlepidopteran females. In some species, 'autodetecting' females possess pheromone receptors and respond to ambient pheromones by altering their mating behavior. Here, we test whether exposure to stereospecific and racemic synthetic pheromones influences calling and subsequent propensity to mate in female swede midge (Contarinia nasturtii Kieffer; Diptera: Cecidomyiidae), a pest of Brassica crops.

RESULTS

In both laboratory and field settings, females exposed to stereospecific and racemic three-component pheromone blends called significantly more frequently and for longer durations than midges in control treatments. In the field, midges were twice as likely to call in pheromone-treated plots versus nontreated plots. Additionally, pheromone pre-exposure reduced subsequent mating: while 68% of female midges mated following control conditions, only 42% and 35% of females pre-exposed to stereospecific and racemic three-component blends mated, respectively.

CONCLUSION

While more frequent calling within pheromone-treated backgrounds may increase the likelihood that females are detected by males, a reduction in female propensity to mate would increase the efficacy of a pheromone-mediated mating disruption system. Our work presents the first known investigation of autodetection behavior in Cecidomyiidae. Additional research is necessary to understand the implications of female autodetection for swede midge management.

Recent Advances in Management by Pheromones of Thaumetopoea Moths in Urban Parks and Woodland Recreational Areas

Caterpillars of the pine processionary moths, Thaumetopoea complex, cause serious defoliation to Cedrus, Pinus, and Pseudotsuga trees. Thaumetopoea caterpillars also have fine hairs on their abdominal tergites that contain a protein that can severely irritate and cause dermatitis in humans and domestic animals. The control of the T. pityocampa pine processionary moth has become necessary in many European countries because of the sanitary risks that are related to larval urtication and the defoliation threat to pine forests and plantations. New research activities have been aimed at the development of eco-friendly, innovative technologies for Integrated Pest Management (IPM) of these moths, particularly in urban parks and woodland recreational areas. This paper describes the recent advances in the use of pheromones in monitoring, mass trapping, and mating disruption related to management of processionary moths T. hellenica and T. pityocampa. According to the results, the use of pheromones may provide a practical alternative to insecticide sprays, as they can be safe and simple as compared to other control methods.

Managing the vine mealybug, Planococcus ficus, through pheromone-mediated mating disruption

The vine mealybug (VMB), Planococcus ficus (Hemiptera: Pseudococcidae), is a key insect pest of vineyards. While pheromone-based mating disruption (MD) has been successfully tested against a wide range of insect pests, knowledge about its efficacy against key mealybug species, such as P. ficus, is scarce. In this study, a novel MD product, Isonet® PF, was evaluated by testing 300, 400, and 500 dispensers/ha at four study sites located in Northern (Veneto) and Southern (Sicily) Italy. Experiments were carried out over 2 years by monitoring the mealybug populations in wine grape and table grape vineyards managed with and without the application of MD. Pheromone dispensers were periodically collected during the grapevine-growing season, extracted, and analyzed by GC-MS, to determine their pheromone content and the release in mg/ha/day. The results showed that use of the MD dispenser Isonet® PF reduced the percentage of VMB-infested bunches and the number of VMB specimens per bunch compared with the untreated controls. This was recorded over 2 years at all experimental sites. Differences in the incidence of infested bunches among the three tested rates of Isonet® PF were not detected. Overall, the results presented here contribute to optimizing the sex pheromone dosage used in MD control programs against VMB allowing a reduction of broad-spectrum insecticides currently employed to manage this important pest.

Identification and Field Evaluation of the Sex Pheromone of Orthaga achatina (Lepidoptera: Pyralidae)

Orthaga achatina (Lepidoptera: Pyralidae) is the most serious pest in south China of camphor trees, Cinnamomum camphora (L.) Presl, an important urban tree species. Gas chromatography-electroantennographic detection (GC-EAD) of the sex pheromone of O. achatina showed three EAD-active components. Coupled gas chromatography/mass spectrometry analyses identified these as (Z)-11-hexadecenol (Z11-16:OH), (Z)-11-hexadecenyl acetate (Z11-16:OAc), and (3Z,6Z,9Z,12Z,15Z)-tricosapentaene (Z3,Z6,Z9,Z12,Z15-23:H). In field tests using different combinations of the three compounds, male moths were attracted to a mixture of Z11-16:OAc and Z3,Z6,Z9,Z12,Z15-23:H, but less attracted to other blends. Further field tests with different ratios of the two compounds determined the optimal ratio of the binary blend as 500:250. The addition of Z11-16:OH to Z11-16:OAc, or to the binary mixture of Z11-16: OAc and the pentaene did not yield higher catches. This shows that O. achatina uses a mixture of Type I and Type II sex pheromone components. Orthaga achatina is the third Pyraloidea species found to utilize Z3,Z6,Z9,Z12,Z15-23:H as a sex pheromone component.

Disrupting mating of Lobesia botrana using sex pheromone aerosol devices

Pheromone-mediated mating disruption (MD) is widely used as a control tool to manage the European grapevine moth (EGVM), Lobesia botrana. Most of the MD formulations are "passive" reservoir dispensers, which need to be used at a rather large number of units per hectare. A promising alternative is represented by automatic aerosol devices, releasing pheromone puffs at programmed time intervals. Herein, we investigated the effectiveness of MD aerosol product Isonet® L MisterX841 in reducing EGVM infestation on grape in comparison to the reference MD product Isonet® L and the grower's standard. Experiments were carried out over 2 years in two different study sites of Aragon region (Spain). EGVM male catches were monitored using traps baited with the female sex pheromone. The effectiveness of MD formulations against the three generations of EGVM was assessed by determining the percentage of infested bunches and the number of nests per bunch. As expected, a much greater amount of male catches in the grower's standard over Isonet® L MisterX841 and Isonet ® L was observed. No significant differences about EGVM male catches were found in vineyards where Isonet® L MisterX841 and Isonet® L were used. EGVM-infested bunches, as well as number of nests per bunch, were higher in the grower's standard, if compared to vineyards where we tested Isonet® L MisterX841 and Isonet® L. However, the employ of the latter led to a lower EGVM bunch infestation, if compared to Isonet® L MisterX841. Overall, the MD approach proposed here is effective against EGVM. These aerosol devices require a lower number of units per hectare if compared to hand-applied dispensers, saving labor costs and contributing to reduce plastic disposal in agricultural settings.

Eco-friendly pheromone dispensers-a green route to manage the European grapevine moth?

The development of environmentally sustainable control strategies to fight insect pests is a key challenge nowadays. Pheromone-mediated mating disruption (MD) is based on the release of synthetic sex attractants into a crop, interfering with mate finding of a given pest species. However, a limited number of research items have been published on the optimization of MD strategies against the European grapevine moth, Lobesia botrana, as well as on the use of biodegradable dispensers to reduce waste production in vineyards, despite the high economic importance of this pest. Therefore, the present study evaluated the efficacy of the MD products Isonet® L TT and the biodegradable Isonet® L TT BIO, applied at various densities, in reducing L. botrana damage on grapevine in comparison to an untreated control and the reference MD product Isonet® L. Experiments were conducted in three different areas of grapevine cultivation, located in Central and Northern Italy, over three different years. Our MD approach allowed a reliable control of the three generations of L. botrana during the whole grape growing season, leading to a significant reduction in the infested flower clusters and bunches, as well as in the number of nests per flower cluster and bunch, if compared to the untreated control. The performances of Isonet® L TT BIO, Isonet® LTT, and Isonet® L did not differ in terms of infested flower clusters/bunches, as well as nests per flower cluster/bunch. This was confirmed in all experimental sites over 3 years of field experiments. Overall, the present research provides useful information for the optimization of MD programs against L. botrana, highlighting the interesting potential of biodegradable pheromone dispensers that can be easily applied at low densities in vineyards, reducing the use of chemical pesticides to control moth pests.

Synthesis of (+)-Disparlure via Enantioselective Iodolactonization

The BINOL-amidine organic catalyst 1 was previously shown to promote highly efficient enantioselective halolactonization reactions of olefinic acids. As part of these studies, it was discovered that the enantioenriched iodolactones could be easily converted into enantioenriched cis-1,2-disubstituted epoxides. This halolactonization-epoxidation sequence was applied to the synthesis of (+)-disparlure, which resulted in the shortest catalytic enantioselective synthesis to date, requiring only five steps and proceeding in 33% yield.

Postharvest Irradiation Treatment for Quarantine Control of the Invasive Lobesia botrana (Lepidoptera: Tortricidae)

Irradiation is a postharvest treatment option for exported berries and berry-like fruits to prevent movement of the quarantine pest European grape vine moth, Lobesia botrana (Denis & Schiffermüller) (Lepidoptera: Tortricidae). The effects of irradiation on egg, larval, and pupal development in L. botrana were examined. Eggs, neonates, third and fifth instars, and early- and late-stage pupae were irradiated at target doses of 50, 100, 150, or 200 Gy or left untreated as controls in replicated factorial experiments, and survival to the adult stage was recorded. Tolerance to radiation generally increased with increasing age and developmental stage. A dose of 150 Gy prevented adult emergence in eggs and larvae. Pupae were more radiotolerant than larvae, and late-stage pupae were more tolerant than early-stage pupae. In large-scale validation tests, 150 Gy applied to fifth instars in diet prevented adult emergence, but some survival occurred in fifth instars irradiated in table grapes; however, 250 Gy prevented fifth instar survival in grapes. For most commodities, the fifth instar is the most radiotolerant life stage likely to occur with the commodity; a minimum radiation dose of 250 Gy will prevent adult emergence from this stage. For traded commodities such as table grapes that may contain L. botrana pupae, 325 Gy applied to mature female pupae sterilized emerging adults and may provide quarantine security. Radiotolerance in L. botrana is comparable to other tortricids, and the data reported here support a generic dose of 250 Gy for eggs and larvae of this group.

Comparison of Attraction and Trapping Capabilities of Bucket- and Delta-Style Traps With Different Pheromone Emission Rates for Gypsy Moths (Lepidoptera: Erebidae): Implications for Understanding Range of Attraction and Utility in Surveillance

Delta- and bucket-style (Universal or Unitrap) traps baited with 1 standard survey lure and 1/3 and 3 lures were compared for their attractiveness and trapping efficiencies for gypsy moth, Lymantria dispar L. (Lepidoptera: Erebidae), males. With bucket traps, the numbers of males attracted to within 2 m of traps and the proportion of these actually captured were identical among the three doses although the percentage of attracted males actually captured in bucket traps was low, less than 15%. A three-lure delta trap attracted about 70% more males than traps with the two lower doses. Capture efficiencies were above 80% for 1/3- and one-lure traps and about 60% for traps baited with three lures. The number of males captured in delta traps was equivalent for the three doses although our observations also suggest that a delta trap baited with three lures drew males from a wider range than lower dose lures and therefore would be a more sensitive trap for detecting incipient populations. We also noted that males tended to arrive in clusters, suggesting that attraction over moderate distances requires periods when the wind direction is fairly constant. This observation coupled with the great variability in the direction of male arrival to the traps also suggests that important changes in the area of influence of the plume are driven in such forested areas by slower but greater changes in wind direction compared with open habitats.

Mining the Volatilomes of Plant-Associated Microbiota for New Biocontrol Solutions

Microbial lifeforms associated with land plants represent a rich source for crop growth- and health-promoting microorganisms and biocontrol agents. Volatile organic compounds (VOCs) produced by the plant microbiota have been demonstrated to elicit plant defenses and inhibit the growth and development of numerous plant pathogens. Therefore, these molecules are prospective alternatives to synthetic pesticides and the determination of their bioactivities against plant threats could contribute to the development of control strategies for sustainable agriculture. In our previous study we investigated the inhibitory impact of volatiles emitted by Pseudomonas species isolated from a potato field against the late blight-causing agent Phytophthora infestans. Besides the well-documented emission of hydrogen cyanide, other Pseudomonas VOCs impeded P. infestans mycelial growth and sporangia germination. Current advances in the field support the emerging concept that the microbial volatilome contains unexploited, eco-friendly chemical resources that could help select for efficient biocontrol strategies and lead to a greener chemical disease management in the field.

First Report of Mating Disruption With an Aggregation Pheromone: A Case Study With Tetropium fuscum (Coleoptera: Cerambycidae)

Tetropium fuscum (F.), native to Europe and established in Nova Scotia, Canada, since at least 1990, is considered a low-to-moderate threat to spruce (Picea spp.) forests in North America and regulated as a quarantine pest by the Canadian Food Inspection Agency. We tested broadcast applications of the aggregation pheromone racemic (5E)-6,10-dimethyl-5,9-undecadien-2-ol (fuscumol), formulated at 10% concentration in Hercon Bio-Flakes (Hercon International, Emigsville, PA), for efficacy in disrupting T. fuscum mating and suppressing populations. Two applications of 2.5-2.75 kg Bio-Flakes (250-275 g a.i.) per ha per season significantly reduced trap catches and mating success (2009, 2010, 2012): about 30% of females trapped in treated plots had mated compared with 60% of females trapped in untreated plots. Similar reductions in mating success were observed in 2011 with one or two 4.5 kg/ha applications of Bio-Flakes. Mean densities of T. fuscum colonizing sentinel bait logs or girdled trees were 36% lower in pheromone-treated plots than in untreated plots, but the difference was not statistically significant. Lack of population suppression may have been because mated females immigrated into treated plots or because populations were so high that despite a 50% reduction in mating success, absolute numbers of mated females were sufficient to infest our bait logs or trees. This is the first demonstration of insect mating disruption via broadcast application of an aggregation pheromone. Pheromone-mediated mating disruption has potential to slow the spread of invasive cerambycids by targeting low-density outlier populations near or beyond the leading edge of an infestation.