Sex Pheromone Aerosol Devices for Mating Disruption: Challenges for a Brighter Future

Simultaneous mating disruption of two moth pests of the vineyard (Lobesia botrana and Cryptoblabes gnidiella) through a biodegradable sex pheromone dispenser

Lobesia botrana (Lepidoptera: Tortricidae) and Cryptoblabes gnidiella (Lepidoptera: Pyralidae) represent a threat to wine production in Mediterranean countries. In recent years, the development of new formulations promoted the spread of pheromone-based mating disruption (MD) as an effective tool for the management of several insect pests in different agricultural contexts. In this study, we investigated the efficacy of an experimental dispenser designed for simultaneous MD of these two pests. The biodegradable double-tube dispenser (Isonet® L CG-BIOX235) was tested for two years in two Italian wine-growing sites, the first in Apulia (Southern Italy), and the second in Tuscany (Central Italy). Isonet® L CG-BIOX235 efficacy was evaluated by testing different doses (i.e., 300, 400, and 500 dispensers/ha), on different varieties (i.e., Aglianico, Syrah, and Viognier), and comparing it with an untreated control. The MD performed using this dispenser significantly reduced the infestation of both L. botrana (i.e., percentage of infested bunches and number of nests per bunch) and C. gnidiella compared to the untreated control, although the occurrence of the latter fluctuated throughout the two-year trials. Overall, although our results underline the possibility of combining the pheromones of the two pests in a single dispenser for their simultaneous MD, they also highlight the need for further studies on some aspects of C. gnidiella biology and consequently improve the MD efficacy against this species.

Functional types of long trichoid sensilla responding to sex pheromone components in Plutella xylostella

Sex pheromones, which consist of multiple components in specific ratios promote intraspecific sexual communications of insects. Plutella xylostella (L.) is a worldwide pest of cruciferous vegetables, the mating behavior of which is highly dependent on its olfactory system. Long trichoid sensilla on male antennae are the main olfactory sensilla that can sense sex pheromones. However, the underlying mechanisms remain unclear. In this study, 3 sex pheromone components from sex pheromone gland secretions of P. xylostella female adults were identified as Z11-16:Ald, Z11-16:Ac, and Z11-16:OH in a ratio of 9.4 : 100 : 17 using gas chromatography - mass spectrometry and gas chromatography with electroantennographic detection. Electrophysiological responses of 581 and 385 long trichoid sensilla of male adults and female adults, respectively, to the 3 components were measured by single sensillum recording. Hierarchical clustering analysis showed that the long trichoid sensilla were of 6 different types. In the male antennae, 52.32%, 5.51%, and 1.89% of the sensilla responded to Z11-16:Ald, Z11-16:Ac, and Z11-16:OH, which are named as A type, B type, and C type sensilla, respectively; 2.93% named as D type sensilla responded to both Z11-16:Ald and Z11-16:Ac, and 0.34% named as E type sensilla were sensitive to both Z11-16:Ald and Z11-16:OH. In the female antennae, only 7.53% of long trichoid sensilla responded to the sex pheromone components, A type sensilla were 3.64%, B type and C type sensilla were both 0.52%, D type sensilla were 1.30%, and 1.56% of the sensilla responded to all 3 components, which were named as F type sensilla. The responding long trichoid sensilla were located from the base to the terminal of the male antennae and from the base to the middle of the female antennae. The pheromone mixture (Z11-16:Ald : Z11-16:Ac : Z11-16:OH = 9.4 : 100 : 17) had a weakly repellent effect on female adults of P. xylostella. Our results lay the foundation for further studies on sex pheromone communications in P. xylostella.

Intercropping Okra and Castor Bean Reduces Recruitment of Oriental Fruit Moth, Grapholita molesta (Lepidoptera: Tortricidae) in a Pear Orchard

Intercrops can lower pest densities by increasing plant diversity, altering chemical communication in the arthropod community, and integrating well with other IPM tactics. We used two years of field observations and Y-tube olfactometer assays to explore the effects of intercropping a pear orchard with okra and castor bean on the cosmopolitan fruit-boring pest Grapholita molesta (Lepidoptera: Tortricidae). Intercropping okra reduced G. molesta trap catches in the pear orchard in both years, and intercropping with castor bean reduced them in the second year. Hydrocarbons, phenols, and ketones predominated in the GC-MS assay of okra volatiles, whereas castor bean volatiles were rich in aldehydes, ketones, and esters. Five of the commercially available volatiles released by these plants exhibited repellency to G. molesta in olfactometer trials, especially cinnamaldehyde, dibutyl phthalate, and thymol; the former compound also exhibited attraction to the egg parasitoid Trichogamma dendrolimi (Hymenoptera: Trichogrammatidae). In addition to their repellent properties, okra and castor bean may enhance integrated control of G. molesta in orchards by hosting prey that support populations of generalist predators that either provide biological pest control services within the orchard ecosystem or generate non-consumptive effects that contribute to pest deterence. Among the plant volatiles evaluated, cinnamaldehyde has the best potential for deployment in orchards to repel G. molesta without disrupting augmentative releases of T. dendrolimi.

Aerosol Alteration of Behavioral Response to Pheromone in Bombyx mori

Because of the complexity to study them, aerosols have been neglected in nearly all studies on olfaction, especially studies dealing with odor capture. However, aerosols are present in large quantities in the atmosphere and have the physico-chemical ability to interact with odor molecules, in particular the many pheromones with low volatility. We submitted male moths of Bombyx mori to bombykol puffs, the main fatty alcohol component of its sex pheromone, depending on whether the air is free of aerosols, charged with ambient concentration aerosols or supplemented with aqueous aerosols and recorded their arousal behavior. Aerosols and pheromone do interact consistently over all experiments and moths react better in low aerosol-concentration conditions. We propose four hypotheses for explaining this impediment, the two most likely resorting to competition between odor molecules and aerosols for the olfactory pores and postulate a reversal to a positive impact of aerosols on communication, depending on the particular physico-chemical properties of the multiphasic interaction. Studying the partitioning between gas and particulate phases in the transport and reception of odors is key for advancing the chemico-physical understanding of olfaction.

Automatic Detection of Moths (Lepidoptera) with a Funnel Trap Prototype

Monitoring insect populations is essential to optimise pest control with the correct protection timing and the avoidance of unnecessary insecticide use. Modern real-time monitoring practices use automatic insect traps, which are expected to be able to estimate the population sizes of pest animals with high species specificity. There are many solutions to overcome this challenge; however, there are only a few data that consider their accuracy under field conditions. This study presents an opto-electronic device prototype (ZooLog VARL) developed by us. A pilot field study evaluated the precision and accuracy of the data filtering using an artificial neural network(ANN) and the detection accuracy of the new probes. The prototype comprises a funnel trap, sensor-ring, and data communication system. The main modification of the trap was a blow-off device that prevented the escape of flying insects from the funnel. These new prototypes were tested in the field during the summer and autumn of 2018, detecting the daily and monthly flight of six moth species (Agrotis segetum, Autographa gamma, Helicoverpa armigera, Cameraria ohridella, Grapholita funebrana, Grapholita molesta). The accuracy of ANN was always higher than 60%. In the case of species with larger body sizes, it reached 90%. The detection accuracy ranged from 84% to 92% on average. These probes detected the real-time catches of the moth species. Therefore, weekly and daily patterns of moth flight activity periods could be compared and displayed for the different species. This device solved the problem of multiple counting and gained a high detection accuracy in target species cases. ZooLog VARL probes provide the real-time, time-series data sets of each monitored pest species. Further evaluation of the catching efficiency of the probes is needed. However, the prototype allows us to follow and model pest dynamics and may make more precise forecasts of population outbreaks.

Sex Pheromone Aerosol Emitters for Lobesia botrana Mating Disruption in Italian Vineyards

Despite the great amount of information on the European Grapevine Moth (EGVM), Lobesia botrana (Lepidoptera: Tortricidae), and the effective strategies available for its management, this moth remains the main key pest damaging grapevines in the Mediterranean and Central Europe wine-growing areas. Synthesizing and manipulating its sex pheromone components fostered the development of new dispensers to boost the effectiveness and sustainability of mating disruption (MD) programs. Recent MD research has highlighted that the effectiveness of aerosol emitters is comparable to that of passive dispensers when applied in large, uniform sites such as Spanish vineyards. However, aerosol emitters that are equally effective in geographical areas characterized by small-sized vineyards, typical of many Italian regions, have not received enough research attention. To face this challenge, herein the experimental aerosol emitter (product code: Isonet^® L MISTERX843) was tested at three different application rates (i.e., 2, 3 and 4 units/ha) in three study sites, two in Tuscany (Central Italy in 2017 and 2018) and one in Emilia-Romagna (Northern Italy in 2017), respectively, for a total of five trials. To assess the efficacy of this novel MD aerosol emitter, three different application densities were compared with an untreated control and two grower's standards. The latter were represented by passive (Isonet^® L TT) and active (Checkmate^® Puffer^® LB) release dispensers, already on the market for EGVM MD and applied at, respectively, 200-300 and 2.5-4 units/ha. MD carried out with Isonet^® L MISTERX843 led to zero catches of males in the pheromone traps. They also allowed for a significant reduction in the number of infested flower clusters and bunches, as well as in the number of nests per flowers cluster/bunch, if compared to the untreated control. As a general trend, MD effectiveness was fully comparable, or even better, if compared to the grower's standard. In conclusion, our research pointed out that the Isonet^® L MISTERX843 can allow for effective EGVM management in small-sized Italian vineyards. Lastly, our economic evaluation showed that the MD whole cost per hectare using active or passive release devices was comparable.

Big Data and Machine Learning to Improve European Grapevine Moth (Lobesia botrana) Predictions

Machine Learning (ML) techniques can be used to convert Big Data into valuable information for agri-environmental applications, such as predictive pest modeling. Lobesia botrana (Denis & Schiffermüller) 1775 (Lepidoptera: Tortricidae) is one of the main pests of grapevine, causing high productivity losses in some vineyards worldwide. This work focuses on the optimization of the Touzeau model, a classical correlation model between temperature and L. botrana development using data-driven models. Data collected from field observations were combined with 30 GB of registered weather data updated every 30 min to train the ML models and make predictions on this pest's flights, as well as to assess the accuracy of both Touzeau and ML models. The results obtained highlight a much higher F1 score of the ML models in comparison with the Touzeau model. The best-performing model was an artificial neural network of four layers, which considered several variables together and not only the temperature, taking advantage of the ability of ML models to find relationships in nonlinear systems. Despite the room for improvement of artificial intelligence-based models, the process and results presented herein highlight the benefits of ML applied to agricultural pest management strategies.

Dispensers for pheromonal pest control

The detrimental effects of pesticides on the environment and human health have motivated the development of alternative pest control strategies. Pheromonal pest control is one alternative strategy that is attractive because most pheromones used commercially are non-toxic. Pheromones are also effective at low concentrations, and insects are slower to develop resistance to them compared to pesticides. Pheromones can be used to control pests by attracting them towards traps, repelling them from crops, or disrupting their mating behaviour. Viability of pheromonal control strategies must be evaluated on a case-by-case basis and depends on the target species, the pheromone being used, the specific control strategy, the method of dispensing pheromone, other pest control strategies pheromones being used alongside, and many other factors. The efficacy of pheromonal control has been demonstrated in commercial applications such as the control of palm weevils using traps releasing their male aggregation pheromone. Mating disruption using female sex pheromones has also been widely applied for control of both the codling moth Cydia Pomonella and the european grapevine moth Lobesia Botrana (Bangels and Beliën, 2012; Lucchi et al., 2018). Pheromones are volatiles that both degrade quickly in the environment and can be rapidly dispersed by wind. Consequently, administering pheromones to fields requires the use of dispensers that emits pheromone continuously or intermittently. Septum dispensers, membrane dispensers and solid matrix dispensers are best suited to treating smaller areas of cropland since they need to be installed by hand, a labor-intensive process. For treating a large area with pheromones, sprayable formulations and aerosol dispensers are alternative dispensing technologies that can be employed. The characteristics of these different dispenser designs are discussed as well as the kinetics governing pheromone release. Possible areas for future work in pheromone dispenser technology include examining new integrated strategies that employ pheromones alongside other pest control techniques in unique ways. The combination of pheromonal control with physical exclusion or predator release are examples of integrated strategies that are promising but have yet to be widely commercialized. Most commercial pheromonal dispensers are also noted to be impossible or impractical to reuse, apart from aerosol devices. Creating new types of rechargeable dispenser might have some cost saving benefits and would be an interesting area for future innovation in this field.

Modular synthesis of the pheromone (2S,7S)-2,7-nonanediyl dibutyrate and its racemate and their field efficacy to control orange wheat blossom midge, Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae)

BACKGROUND

Sudden outbreaks of the orange wheat blossom midge, Sitodiplosis mosellana (Géhin) cause huge wheat yield losses. Use of sex pheromones is more efficient than laborious egg counting to monitor these hidden-concealed insects. Quick synthesis of the sex pheromones is therefore required to meet the sudden outbreak needs.

RESULTS

A synthetic approach of stereospecific and racemic S. mosellana pheromones was presented. This method afforded the stereospecific and racemic S. mosellana pheromones in three steps and high enantioselectivity (> 98% ee for (2S,7S)-2,7-nonanediyl dibutyrate) in less than 1 day with 74% and 73% overall yields, respectively, whereas most conventional methods require longer synthesis time with less than 40% yield. The synthesis routes could quickly and economically afford the pheromones, starting from synthon (S)-but-3-yn-2-ol (1a) or but-3-yn-2-ol (1b), through the same three-step processes of coupling, reduction, and esterification. The Y-tube olfactometer results showed significant attractiveness of the synthetic stereospecific and racemic sex pheromones to S. mosellana males relative to the blank control (P < 0.001). Field trials also demonstrated significant attractiveness of the synthetic stereospecific and racemic sex pheromones relative to the blank control (P < 0.001).

CONCLUSION

This modular approach is conducive to the deployment of field traps and timely responses to S. mosellana outbreaks and can be a time-saving and cost-effective tool to manage S. mosellana. © 2022 Society of Chemical Industry.

Molecular characterization of insulin receptor (IR) in oriental fruit moth, Grapholita molesta (Lepidoptera: Tortricidae), and elucidation of its regulatory roles in glucolipid homeostasis and metamorphosis through interaction with miR-982490

As an intermediate molecule in the Insulin/Insulin-like growth factor signalling pathway (IIS), the insulin receptor (IR) plays vital roles linking nutritional signals to the downstream regulation of metabolic homeostasis, development, metamorphosis, reproduction and stress responses. In the present study, we describe the molecular characteristics of IR in the cosmopolitan fruit boring pest, Grapholita molesta, and its predicted posttranscription regulator miR-982490, and elucidate its regulatory roles in glucolipid homeostasis and metamorphosis. Phylogenetic and domain analyses indicate that lepidopteran IRs normally cluster within families, and that four main domains are conserved in GmIR and those of other Lepidoptera. Bio-informatic prediction, synchronic expression profile evaluation and dual luciferase reporter assays indicated negative regulation of GmIR by miR-982490. Injection of miR-982490 agomir into fifth instar larvae yielded effects similar to dsGmIR injection, resulting in enhanced levels of trehalose and triglyceride in haemolymph, and reduced pupation success and pupal weight, both of which could be rescued by co-injection of dsGmIR and miR-982490 antagomir. We infer that GmIR regulates glucolipid homeostasis and affects G. molesta metamorphosis via interactions with its posttranscriptional regulator miR-982490. This study expands our understanding of the regulatory network of IIS in insect nutritional homeostasis and development.

Diel Periodicity in Males of the Navel Orangeworm (Lepidoptera: Pyralidae) as Revealed by Automated Camera Traps

Navel orangeworm, Amyelois transitella (Walker), is a key pest of walnuts, pistachio, and almonds in California. Pheromone mating disruption using timed aerosol dispensers is an increasingly common management technique. Dispenser efficiency may be increased by timing releases with the active mating period of navel orangeworm. Past work found that the peak time of sexual activity for navel orangeworm females is 2 h before sunrise when temperatures are above 18°C. Inference of male responsiveness from data collected in that study was limited by the necessity of using laboratory-reared females as a source of sex pheromone emission to attract males and the inherent limitations of human observers for nocturnal events. Here we used camera traps baited with artificial pheromone to observe male navel orangeworm mating response in the field over two field seasons. Male response to synthetic pheromone exhibited diel patterns broadly similar to females, i.e., they were active for a brief period of 2-3 h before dawn under summer conditions and began responding to pheromone earlier and over a longer period of time during spring and fall. But contrary to the previous findings with females, some males were captured at all hours of the day and night, and there was no evidence of short-term change of pheromone responsiveness in response to temperature. Environmental effects on the response of navel orangeworm males to an artificial pheromone source differ in important ways from the environmental effects on female release of sex pheromone.

Insights Into Chemosensory Proteins From Non-Model Insects: Advances and Perspectives in the Context of Pest Management

Nowadays, insect chemosensation represents a key aspect of integrated pest management in the Anthropocene epoch. Olfaction-related proteins have been the focus of studies due to their function in vital processes, such ashost finding and reproduction behavior. Hence, most research has been based on the study of model insects, namely Drosophila melanogaster, Bombyx mori or Tribolium castaneum. Over the passage of time and the advance of new molecular techniques, insects considered non-models have been studied, contributing greatly to the knowledge of insect olfactory systems and enhanced pest control methods. In this review, a reference point for non-model insects is proposed and the concept of model and non-model insects is discussed. Likewise, it summarizes and discusses the progress and contribution in the olfaction field of both model and non-model insects considered pests in agriculture.

High-resolution weather network reveals a high spatial variability in air temperature in the Central valley of California with implications for crop and pest management

Weather is the most important driver of crop development. However, spatial variability in weather makes it hard to obtain reliable high resolution datasets across large areas. Most growers rely on data from a single station that can be up to 50km away to make decisions about irrigation, pest management and penology-associated cultural practices at the block level. In this regard, we hypothesize that kriging a large network of weather stations can improve thermal time data quality compared to using the closest station. This study aims to explore the spatial variability in California's Central Valley and what is the relationship between the density of weather stations used and the error in the measurement of temperature related metrics and derived models. For this purpose, we used temperature records from January 1st 2020 to March 1st 2021 collected by the California Irrigation Management Information System (CIMIS) and a system of 731 weather stations placed above the canopy of trees in commercial orchards (in-orchard). We observed large discrepancies (>300 GDDTb0) in thermal time accumulation between using an interpolation of all stations available and just using the closest CIMIS station. Our data suggests these differences are not systematic bias but true differences in mesoclimate. Similar results were observed for chill accumulation in areas especially prone to not meeting pistachio chill requirements where the discrepancies between using the site-specific in-orchard weather station network and not using them were up to 10 CP. The use of this high resolution network of weather stations revealed spatial patterns in grape, almond, pistachio and pests phenology not reported before. Whereas previous studies have been focused on predictions at the county or state or regional level, our data suggests that a finer resolution can result in major improvements in the quality of data crucial for crop decision making.

Helicoverpa armigera and Helicoverpa zea hybridization: constraints, heterosis, and implications for pest management

BACKGROUND

The invasion of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) into the New World has made it possible for this pest to hybridize with a native American species, H. zea (Boddie), under natural conditions. We investigated the viability and development of hybrids of these two Helicoverpa species. We reared the parental species and evaluated crosses between H. armigera males and H. zea females and vice versa, two intercrosses between hybrids, and eight backcrosses between hybrids and parental species. We estimated the length of immature stages, fecundity, survival, sex ratio, and heterosis.

RESULTS

Although hybridization occcurred, with heterosis during the development of immatures, reproductive incompatibilities also were observed between the parental species and between hybrids from subsequent crosses. The interspecific crosses between hybrids and backcrosses confirmed the possibility of introgression events and their perpetuation in field populations. The results indicate that hybridization events are favored at high population levels, while at low population levels the 'species identities' will be maintained.

CONCLUSIONS

The possibility of interspecific gene flow and its perpetuation through successive crosses and backcrosses suggests several recommenations for management. Populations of both species should be maintained at an equilibrium level to reduce the chance of interspecific crosses, which are presumably more likely to occur during pest outbreaks. The existence of hybridization and resistance to different active pesticide ingredients should be monitored. All practices related to managing the resistance of these pests to chemical and biological insecticides should be systematized to reduce the chance of selecting for resistant individuals.

Suspension of pheromone microcapsules on vine leaves acting as passive dispensers against pests

Pheromones are increasingly used as alternatives to pesticides to protect vineyards against L. botrana, a key grape pest. To diffuse (7E,9Z)-7,9-dodecadien-1-ylacetate, the L. botrana pheromone, passive, or aerosol dispensers are commonly applied. This paper deals with another method based on spraying an aqueous formulation, Lobesia Pro Spray, containing the pheromone encapsulated in a resin. The objectives were to assess the ability of vine leaves to act as pheromone dispensers and to check that encapsulation protects the plant from pheromone penetration. Laboratory testing based on an emission cell combined with airborne pheromone measurements by active sampling on sorbent tubes followed by ATD-GC-MS analysis was developed to accurately characterise the release of the pheromone into the air. Release kinetics analysis performed on the vine leaves showed a high pheromone release (about 30% of the sprayed quantity) the first day of the test. The release rate then decreased rapidly to reach about 650 mg/day/ha after 4 days. Kinetic modelling showed that it would be possible to maintain an effective airborne concentration of pheromone for approximately 12 days. Release tests were also carried out on glass, PVC and blotting paper. The results obtained showed that the vine leaves behaved as a non-absorbent material, implying that the pheromone used in the Lobesia Pro Spray formulation did not penetrate the plant. These first results prove the feasibility of using vine leaves as pheromone dispensers for a sprayed formulation and the ability to optimise the treatment conditions (dose and frequency) through laboratory testing.

A Comprehensive Review of the Coffee Leaf Miner Leucoptera coffeella (Lepidoptera: Lyonetiidae)-A Major Pest for the Coffee Crop in Brazil and Others Neotropical Countries

Simple Summary

Coffee is produced in more than 60 countries by 25 million coffee producers, most of whom are smallholders in emergent countries. More than a beverage intake, coffee has become a ritual for an increasing number of consumers across the globe. This rising market demands modern management to improve grain quality, environment protecting, and produce pesticide-free products. Among several challenges to overcome, the coffee leaf miner (CLM) pest is one of the most severe threats to the coffee crop, especially in neotropical countries, such as Brazil, the world’s largest producer. Responsible for losses ranging from 30–70%, the CLM impairs the grain production and quality, which negatively reflects on the coffee production chain. Drawback aspects caused by chemical control with pesticides, such as the harmful effects to human health and environment and the selection of resistant-insect populations, prompt scientists to improve integrated pest management (IPM) tools. Therefore, the development of new resistant cultivars, biological control, nano-biopesticide products and other approaches are important strategies to a sustainable CLM control design. This review addresses basic knowledge of the insect L. coffeella and proposes novel insights for an IPM view.

Abstract

The coffee leaf miner (CLM) Leucoptera coffeella moth is a major threat to coffee production. Insect damage is related to the feeding behavior of the larvae on the leaf. During the immature life stages, the insect feeds in the mesophyll triggering necrosis and causing loss of photosynthetic capacity, defoliation and significant yield loss to coffee crops. Chemical control is used to support the coffee production chain, though market requirements move toward conscious consumption claiming for more sustainable methods. In this overview, we discuss aspects about the CLM concerning biology, history, geographical distribution, economic impacts, and the most relevant control strategies in progress. Insights to develop an integrated approach for a safer and eco-friendly control of the CLM are discussed here, including bio-extracts, nanotechnology, pheromones, and tolerant cultivars.

Mating Disruption of the Olive Moth Prays oleae (Bernard) in Olive Groves Using Aerosol Dispensers

Simple Summary

According to official data, the world production of olive oil in the 2020–2021 period was about 3,197,000 tons; in the EU alone, the number of olive trees is over 737 million. The olive moth Prays oleae is one of the most damaging and devastating olive tree pests in the Mediterranean basin. Damage caused by this moth can reduce production by 50–60%, causing large losses in olive oil production. The use of an insect pheromone mating disruption strategy is a sustainable and environmentally friendly tool for Integrated Pest Management, reducing the use of chemical pesticides to control olive pests. In the present study, a mating disruption system based on aerosol dispensers was developed to control P. oleae moth populations. Overall, our results demonstrated at all experimental sites over 2 years that mating disruption using aerosols in the management of P. oleae registered a high suppression of male captures, as well as significantly reducing affected inflorescence and fruit infestation when compared to the untreated control.

Abstract

The olive moth (OM), Prays oleae (Bern.) (Lepidoptera: Yponomeutidae), is a major olive grove pest worldwide; however, until now, very few studies have investigated the effectiveness of mating disruption (MD) techniques against this pest. Experiments were carried out for two successive years (2019 and 2020) in three different olive groves in Andalucía (Southern Spain) to evaluate mating disruption’s efficacy in controlling the OM from the first to the third generation. The effectiveness of MD formulations against the three generations of OM was assessed by determining the percentage of infested olive fruits, the reduction of pheromone trap catches, and the number of affected inflorescences in both MD-treated and untreated control olive groves. The number of release points (one or two aerosol devices per ha) was also evaluated. In all years and trials, the mean number of males caught in traps placed in the MD-treated plots was significantly lower than untreated sites. Mating disruption registered a high suppression of male captures (>75%) in treated plots for two consecutive seasons. Concerning infested olive fruits, substantial reductions (about 80%) were observed in the MD plots of locations B and C, and a reduction of about 40% was detected in location A, compared to the control plot. Results showed that the installation of two aerosol devices/ha reduced fruit damage below 20% of infested olive fruits except for one site where a reduction of about 71% in the MD plot was recorded in 2019. Although few significant differences were associated with OM male catches and infested olive fruits between plots treated with one aerosol/ha and two aerosols/ha in most of the comparisons, significant differences in the number of olive inflorescences infested by P. oleae were found, suggesting a similar performance between the two tested aerosol densities. Results of two-year field trials in Andalucía demonstrated the potential of Mister P X841 aerosol devices as an effective tool for controlling the olive moth, P. oleae.

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.

Pheromone Deployment Strategies for Mating Disruption of a Vineyard Mealybug

The mealybug, Planococcus ficus (Signoret), is a primary vineyard pest in California and other grape-growing regions throughout the World. Mating disruption programs are commercially available to manage Pl. ficus, but widespread adoption has been limited, in part, by high costs compared with insecticide programs. To improve mating disruption economic effectiveness, different deployment technologies (passive, aerosol, and microencapsulated formulations) were individually examined. Adult male Pl. ficus captures in pheromone traps and categorical ratings of vine infestation or crop damage suggest that all deployment strategies lowered mealybug densities or damage. Using passive dispensers, deployment rates of 310 and 465 per ha lowered Pl. ficus crop damage similar to 615 per ha, a rate commonly used in commercial operations; reduced rates would lower product and deployment costs. Meso dispensers, containing more a.i., deployed at 35 per ha did not have a treatment impact, but a microencapsulated formulation and aerosol canisters lowered male flight captures and/or crop damage. Male mealybug flight activity was greatest from 0500-1100 hr, which coincided with temperatures >16° and <32°C. These restricted times and temperatures suggest programable dispensers might allow pheromone deployment to coincide only with flight patterns. A large field trial using passive dispensers found greater treatment separation after 3 yr of pheromone deployment. Discrepancies in results among vineyards may be related to Pl. ficus density, but combined results from all trials suggest that different deployment technologies can be used to impact Pl. ficus densities and damage, even at reduced rates, especially with continued use over multiple seasons.

Developments in Fatty Acid-Derived Insect Pheromone Production Using Engineered Yeasts

The use of traditional chemical insecticides for pest control often leads to environmental pollution and a decrease in biodiversity. Recently, insect sex pheromones were applied for sustainable biocontrol of pests in fields, due to their limited adverse impacts on biodiversity and food safety compared to that of other conventional insecticides. However, the structures of insect pheromones are complex, and their chemical synthesis is not commercially feasible. As yeasts have been widely used for fatty acid-derived pheromone production in the past few years, using engineered yeasts may be promising and sustainable for the low-cost production of fatty acid-derived pheromones. The primary fatty acids produced by Saccharomyces cerevisiae and other yeasts are C16 and C18, and it is also possible to rewire/reprogram the metabolic flux for other fatty acids or fatty acid derivatives. This review summarizes the fatty acid biosynthetic pathway in S. cerevisiae and recent progress in yeast engineering in terms of metabolic engineering and synthetic biology strategies to produce insect pheromones. In the future, insect pheromones produced by yeasts might provide an eco-friendly pest control method in agricultural fields.

Production of Volatile Moth Sex Pheromones in Transgenic Nicotiana benthamiana Plants

Plant-based bioproduction of insect sex pheromones has been proposed as an innovative strategy to increase the sustainability of pest control in agriculture. Here, we describe the engineering of transgenic plants producing (Z)-11-hexadecenol (Z11-16OH) and (Z)-11-hexadecenyl acetate (Z11-16OAc), two main volatile components in many Lepidoptera sex pheromone blends. We assembled multigene DNA constructs encoding the pheromone biosynthetic pathway and stably transformed them into Nicotiana benthamiana plants. The constructs contained the Amyelois transitella AtrΔ11 desaturase gene, the Helicoverpa armigera fatty acyl reductase HarFAR gene, and the Euonymus alatus diacylglycerol acetyltransferase EaDAct gene in different configurations. All the pheromone-producing plants showed dwarf phenotypes, the severity of which correlated with pheromone levels. All but one of the recovered lines produced high levels of Z11-16OH, but very low levels of Z11-16OAc, probably as a result of recurrent truncations at the level of the EaDAct gene. Only one plant line (SxPv1.2) was recovered that harboured an intact pheromone pathway and which produced moderate levels of Z11-16OAc (11.8 μg g-1 FW) and high levels of Z11-16OH (111.4 μg g-1). Z11-16OAc production was accompanied in SxPv1.2 by a partial recovery of the dwarf phenotype. SxPv1.2 was used to estimate the rates of volatile pheromone release, which resulted in 8.48 ng g-1 FW per day for Z11-16OH and 9.44 ng g-1 FW per day for Z11-16OAc. Our results suggest that pheromone release acts as a limiting factor in pheromone biodispenser strategies and establish a roadmap for biotechnological improvements.

Pheromone-Mediated Mating Disruption as Management Option for Cydia spp. in Chestnut Orchard

(1) Background: Pheromone-based devices are successfully used to control insect pests in agriculture. (2) Methods: Investigations were conducted to evaluate the effectiveness of mating disruption (MD) to control the chestnut tortrix moths, Cydia fagiglandana and Cydia splendana. Surveys were performed in northern Italy in 2019-2020. MD was carried out using the pheromone dispenser Ecodian^® CT. The effectiveness of MD was assessed by recording male adult catches in pheromone-baited sticky traps and larvae in chestnut fruits, comparing MD and control plots. (3) Results: The total number of trapped males was significantly lower in MD plots than in control ones, for all sites and years. Trap catch suppression in MD plots averaged 89.5% and 93.8% for C. fagiglandana and 57.4% and 81% for C. splendana in 2019 and 2020, respectively. The larval infestation rate in fruits did not vary between plots except for one site where a reduction of about 71% in the MD plot was recorded in 2019. (4) Conclusions: Low catches in MD plots turned out to be a good measure of the effectiveness of communication disruption, but no satisfactory data have been obtained regarding fruit infestation, highlighting how the reduction of male catches cannot always be considered as a reliable indicator of successful control. Specific investigations about background population density, dispersal and mating/oviposition behavior are thus essential for a viable management strategy.

From Insect Pheromones to Mating Disruption: Theory and Practice

Insects perceive and integrate a hierarchy of visual, chemical and tactile cues for feeding and reproductive purposes, as well as for predator and parasitoid avoidance [...].

Laboratory and field studies supporting augmentation biological control of oriental fruit moth, Grapholita molesta (Lepidoptera: Tortricidae), using Trichogramma dendrolimi (Hymenoptera: Trichogrammatidae)

BACKGROUND

Oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae) is a cosmopolitan pests of fruit trees in temperate regions. Control of G. molesta is challenging because larvae feed in concealed locations and have evolved resistance to many pesticides. We compared three commercially available species of Trichogramma for efficacy against G. molesta in the laboratory assays and tested releases of the promising species in a pear orchard.

RESULTS

Laboratory assays indicated that Trichogramma dendrolimi parasitized G. molesta at the highest rate. Parasitoids took longer to oviposit in older host eggs, and fewer eggs were parasitized when they were more than 3 days old. Field tests produced ca 60% cumulative parasitism of sentinel G. molesta eggs with one release of Trichogramma dendrolimi, with most parasitism occurring within 24 h. Female wasps dispersed up to 12 m from release points with a bias toward upwind movement.

CONCLUSION

We calculated that, for each generation of G. molesta, 900 000 wasps per hectare, in three releases 3 days apart, each distributed among release points 10 m apart, would reduce fruit damage by half in an orchard where 50% of fruit would otherwise be damaged. Although augmentation of Trichogramma dendrolimi is a viable tactic for reducing G. molesta populations and fruit damage, it will require integration with other compatible control tactics in order to provide commercially acceptable levels of control in orchards experiencing significant pest pressure. © 2021 Society of Chemical Industry.

Optimal Pest Control Strategies with Cost-effectiveness Analysis

Pest and plant diseases cause damages and economic losses, threatening food security and ecosystem services. Thus, proper pest management is indispensable to mitigate the risk of losses. The risk of environmental hazards induced by toxic chemicals alongside the rapid development of chemical resistance by insects entails more resilient, sustainable, and ecologically sound approaches to chemical methods of control. This study evaluates the application of three dynamical measures of controls, namely, green insecticide, mating disruption, and the removal of infected plants, in controlling pest insects. A model was built to describe the interaction between plants and insects as well as the circulation of the pathogen. Optimal control measures are sought in such a way they maximize the healthy plant density jointly with the pests' density under the lowest possible control efforts. Our simulation study shows that all strategies succeed in controlling the insects. However, a cost-effectiveness analysis suggests that a strategy with two measures of green insecticide and plant removal is the most cost-effective, followed by one which applies all control measures. The best strategy projects the decrease of potential loss from 65.36% to 6.12%.

Mating Disruption of Pseudococcus calceolariae (Maskell) (Hemiptera, Pseudococcidae) in Fruit Crops

Simple Summary

The citrophilous mealybug is an economically important pest that is mainly controlled using insecticides, not always successfully, and with unintended negative environmental side effects. In our research, we tested a specific and sustainable control tool using the mealybug sex pheromone. Mating disruption is a technique that aims to reduce mating between males and females by inundating the area with the synthetic sex pheromone of the species, thereby reducing reproduction and consequently populations over time and damage. For this purpose, the mealybug pheromone, incorporated into a polymeric substance for its release, was applied in a tangerine and an apple orchard, in two seasons (2017/2018 and 2019/2020). In all seasons, a reduction in the males catches in traps after deploying pheromone was observed, which would indicate a decrease in the probability of successful mating compared to control plots. The duration of this effect was around one year. Mealybug abundance on trees was extremely low throughout the trials, so it was not possible to observe a reduction of populations or damage. This research shows that the use of this pheromone-based technique has good potential for controlling the citrophilous mealybug, with the advantage of being environmentally friendly and non-toxic.

Abstract

Pseudococcus calceolariae, the citrophilous mealybug, is a species of economic importance. Mating disruption (MD) is a potential control tool. During 2017–2020, trials were conducted to evaluate the potential of P. calceolariae MD in an apple and a tangerine orchard. Two pheromone doses, 6.32 g/ha (2017–2018) and 9.45 g/ha (2019–2020), were tested. The intermediate season (2018–2019) was evaluated without pheromone renewal to study the persistence of the pheromone effect. Male captures in pheromone traps, mealybug population/plant, percentage of infested fruit at harvest and mating disruption index (MDI) were recorded regularly. In both orchards, in the first season, male captures were significantly lower in MD plots compared to control plots, with an MDI > 94% in the first month after pheromone deployment. During the second season, significantly lower male captures in MD plots were still observed, with an average MDI of 80%. At the third season, male captures were again significant lower in MD than control plots shortly after pheromone applications. In both orchards, population by visual inspection and infested fruits were very low, without differences between MD and control plots. These results show the potential use of mating disruption for the control of P. calceolariae.

Individual and Additive Effects of Insecticide and Mating Disruption in Integrated Management of Navel Orangeworm in Almonds

Simple Summary

Mating disruption is an increasingly important part of pest management for the navel orangeworm Amyelois transitella. Industry groups have long supported mating disruption research and development with the divergent objectives of both minimizing damage from this key pest and reducing insecticide used on these crops. It is therefore important to know whether the benefits of mating disruption and insecticide are additive or, alternatively, if using both together provides no additional benefit over either alone. Ten years of data from research trials in a large commercial almond orchard found that the benefits of mating disruption are generally additive with lower damage if both are used together than either alone. Substantial year-to-year variability in navel orangeworm damage was also evident, even with stringent management. These findings indicate that the combination of mating disruption and insecticide can reduce the impact of navel orangeworm damage on the almond industry. Further improvements in monitoring and predictions of navel orangeworm abundance and damage are necessary for mating disruption to effectively contribute to the industry goal of reduction of insecticide use by 25%.

Abstract

Damage from Amyelois transitella, a key pest of almonds in California, is managed by destruction of overwintering hosts, timely harvest, and insecticides. Mating disruption has been an increasingly frequent addition to these management tools. Efficacy of mating disruption for control of navel orangeworm damage has been demonstrated in experiments that included control plots not treated with either mating disruption or insecticide. However, the navel orangeworm flies much farther than many orchard pests, so large plots of an expensive crop are required for such research. A large almond orchard was subdivided into replicate blocks of 96 to 224 ha and used to compare harvest damage from navel orangeworm in almonds treated with both mating disruption and insecticide, or with either alone. Regression of navel orangeworm damage in researcher-collected harvest samples from the interior and center of management blocks on damage in huller samples found good correlation for both and supported previous assumptions that huller samples underreport navel orangeworm damage. Blocks treated with both mating disruption and insecticide had lower damage than those treated with either alone in 9 of the 10 years examined. Use of insecticide had a stronger impact than doubling the dispenser rate from 2.5 to 5 per ha, and long-term comparisons of relative navel orangeworm damage to earlier- and later-harvested varieties revealed greater variation than previously demonstrated. These findings are an economically important confirmation of trade-offs in economic management of this critical pest. Additional monitoring tools and research tactics will be necessary to fulfill the potential of mating disruption to reduce insecticide use for navel orangeworm.

Management of Navel Orangeworm (Lepidoptera: Pyralidae) Using Four Commercial Mating Disruption Systems in California Almonds

The navel orangeworm, Amyelois transitella (Walker), is the most significant pest of California almonds. Direct feeding on the kernel by the larvae causes reductions in salable crop, crop quality, and exportability. Pheromone mating disruption (MD) targeting navel orangeworm is a relatively new technique with the potential to improve management. In 2017, we used replicated ~16-ha plots to compare the efficacy of four commercial MD systems (CheckMate, Cidetrak, Isomate, and Semios) for their relative impacts on the number of navel orangeworm in monitoring traps and crop quality. From 2017 to 2018, we conducted nine direct comparison studies in 16 to 40 ha almond orchards to compare conventional pest management programs to programs incorporating pheromone MD systems. Across all studies, MD reduced male moth captures in pheromone traps by >94%. In the efficacy study, use of mating disruption led to 35% and 53% reductions in kernel damage in Nonpareil and pollinizer cultivars, respectively, and an average increase in crop value of $370 ha-1. In the direct comparison, kernel damage to Nonpareil and pollinizer cultivars was reduced by 65% and 78%, respectively, resulting in an average increase in crop value of $357 ha-1. Economic analyses showed that increases in crop returns exceeded the costs of implementing MD systems with the break-even point ranging from 0.86 to 1.06% of kernel damage. These results suggest that adding MD to an existing navel orangeworm management program is a cost-effective way to reduce damage while promoting sustainable pest management practices.

Optimization and field demonstration of the Lygus pratensis (Hemiptera: Miridae) sex pheromone

BACKGROUND

The plant bug Lygus pratensis Linnaeus is a widely distributed polyphagous herbivore that increasingly attains outbreak population levels on cotton in northwestern China. Although the sex pheromone of L. pratensis from the United Kingdom has been identified as hexyl butyrate, (E)-2-hexenyl butyrate and (E)-4-oxo-2-hexenal, at a ratio of 100:25:24, this volatile blend does not prove attractive to Chinese field populations.

RESULTS

In this study, we identified and optimized the sex pheromone of L. pratensis strains from northwestern China. In coupled gas chromatography and electro-antennogram detection (GC-EAD) assays, three compounds within whole-body extracts of virgin L. pratensis females elicited antennal responses: hexyl butyrate, (E)-2-hexenyl butyrate and (E)-4-oxo-2-hexenal. In field trials, a 20:1:30 ratio blend was the most attractive to L. pratensis males.

CONCLUSION

Traps baited with this synthetic pheromone blend present considerable advantages over traditional sweep-net sampling for L. pratensis population monitoring. It can readily be incorporated into monitoring schemes and integrated pest management packages.

Persistence of Mating Suppression of the Indian Meal Moth Plodia Interpunctella in the Presence and Absence of Commercial Mating Disruption Dispensers

The Indian meal moth Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), is controlled by commercial mating disruption dispensers using passive release to emit high concentrations (relative to females or monitoring lures) of their principal sex pheromone component, (9Z,12E)-tetradecadienyl acetate. Since P. interpunctella is sexually active throughout the scotophase, an assay system was developed to determine the importance of direct interaction of the male with the dispenser, and whether exposure to mating disruption early in the night is sufficient to suppress mating throughout the night. Exposure to mating disruption dispensers in the mating assay chamber for the first two hours of a 10-h scotophase significantly reduced mating when females were introduced four hours later. Mating was also reduced to a lesser degree in a concentration-dependent manner based solely on re-emission of pheromone, and when males were exposed outside the mating assay chamber. These results indicate that the commercial mating disruption dispensers can suppress mating throughout the night based on interaction with the dispenser early in the night. Desensitization resulting from attraction to a high-concentration pheromone source is important to this suppression, but other factors such as re-emission from the environment may also have a role. These observations imply a non-competitive mechanism for P. interpunctella with the product studied, and suggest that effectiveness of the mating disruption dispenser might be augmented by using them in conjunction with another formulation such as an aerosol or micro-encapsulated product.

Developing a Highly Stable Carlina acaulis Essential Oil Nanoemulsion for Managing Lobesia botrana

The growing interest in the development of green pest management strategies is leading to the exploitation of essential oils (EOs) as promising botanical pesticides. In this respect, nanotechnology could efficiently support the use of EOs through their encapsulation into stable nanoformulations, such as nanoemulsions (NEs), to improve their stability and efficacy. This technology assures the improvement of the chemical stability, hydrophilicity, and environmental persistence of EOs, giving an added value for the fabrication of natural insecticides effective against a wide spectrum of insect vectors and pests of public and agronomical importance. Carlina acaulis (Asteraceae) root EO has been recently proposed as a promising ingredient of a new generation of botanical insecticides. In the present study, a highly stable C. acaulis-based NE was developed. Interestingly, such a nanosystem was able to encapsulate 6% (w/w) of C. acaulis EO, showing a mean diameter of around 140 nm and a SOR (surfactant-to-oil ratio) of 0.6. Its stability was evaluated in a storage period of six months and corroborated by an accelerated stability study. Therefore, the C. acaulis EO and C. acaulis-based NE were evaluated for their toxicity against 1st instar larvae of the European grapevine moth (EGVM), Lobesia botrana (Denis & Schiffermüller, 1775) (Lepidoptera: Tortricidae), a major vineyard pest. The chemical composition of C. acaulis EO was investigated by gas chromatography-mass spectrometry (GC-MS) revealing carlina oxide, a polyacetylene, as the main constituent. In toxicity assays, both the C. acaulis EO and the C. acaulis-based NE were highly toxic to L. botrana larvae, with LC₅₀ values of 7.299 and 9.044 µL/mL for C. acaulis EO and NE, respectively. The C. acaulis-based NE represents a promising option to develop highly stable botanical insecticides for pest management. To date, this study represents the first evidence about the insecticidal toxicity of EOs and EO-based NEs against this major grapevine pest.

Development of a Mating Disruption Program for a Mealybug, Planococcus ficus, in Vineyards

Simple Summary

The vine mealybug is a key insect pest of vineyards that currently is controlled by one or more insecticide applications per season. Here, we sought to develop a more sustainable control tool by using the mealybug’s sex pheromone to reduce mating and thereby lower pest damage. The mature female mealybug emits a sex pheromone that the winged adult male uses to find and mate with females. Synthetically produced sex pheromone, specific to the vine mealybug, was enclosed in commercial dispensers and deployed in vineyards in 2004–2007 studies to determine if mating disruption could provide a viable control option. Trials were conducted in commercial vineyards with cooperating farmers. Across all trials, mating disruption reduced pheromone trap captures of adult male mealybugs—an indication that the population numbers were lowered—and there was often a reduction mealybug numbers on vines and/or crop damage. There was not a clear reduction in the proportion of female mealybugs with ovisacs (a cottony-like mass containing mealybug eggs), but this may have resulted from the production of non-viable ovisacs that were not differentiated in the field samples. Pheromone trap captures were never lowered to zero (often called trap shut down), possibly because trials were conducted in vineyards with unusually high mealybug densities. Trap capture patterns commonly began low in April-May, increased in mid-July or August, and often decreased in September–October when post-harvest insecticides were applied. Results over all years suggest season-long coverage or late season coverage may be as or more important than dose per hectare. This research was used to help initiate the commercialization of mating disruption products for the vine mealybug, which are now being successfully used throughout the world’s grape-growing regions where this pest is found.

Abstract

The vine mealybug (VMB), Planococcus ficus (Hemiptera: Pseudococcidae), is a key insect pest of vineyards, and improvements in sustainable control of this pest are needed to meet increasing consumer demand for organically farmed products. One promising option is mating disruption. In a series of experiments conducted from 2004 to 2007, we tested the effects of mating disruption on trap captures of Pl. ficus males in pheromone-baited traps, on Pl. ficus numbers and age structure on vines, and on damage to grape clusters. From 2004 to 2005, the effects of dispenser load (mg active ingredient per dispenser) were also assessed, and dispensers were compared to a flowable formulation. Across all trials, mating disruption consistently reduced pheromone trap captures and often reduced mealybug numbers on vines and/or crop damage, regardless of the pheromone dose that was applied. Reductions in Pl. ficus densities in mating disruption plots were not accompanied by clear effects on mealybug population age structure; however, production of non-viable ovisacs by unmated females may have obscured differences in proportional representation of ovisacs. Pheromone trap captures were never lowered to zero (often called trap shut down), possibly because trials were conducted in vineyards with unusually high Pl. ficus densities. Trap-capture patterns in both treated and control plots commonly began low in April–May, increased in mid-July or August, and often decreased in September–October when post-harvest insecticides were applied. During the four-year trial, the release rate from plastic sachet dispensers was improved by industry cooperators as pheromone was released too quickly (2004) or not completely released during the season (2005–2006). The flowable formulation performed slightly better than dispensers at the same application dose. Results over all years suggest season-long coverage or late-season coverage may be as or more important than dose per hectare. Development of a dispenser with optimized season-long pheromone emission or targeted seasonal periods should be a future goal.

Factors Affecting Disruption of Navel Orangeworm (Lepidoptera: Pyralidae) Using Aerosol Dispensers

Mating disruption is used to help manage the navel orangeworm on approximately 200,000 ha of tree nut crops. Aerosol dispensers are the most common formulation, and all formulations use an incomplete pheromone blend consisting solely of (Z11,Z13)-hexadecadienal. Profile analysis (examination of capture and males in pheromone traps as a function of spatial density of dispensers) demonstrated a sharp drop of males captured with a very low density of dispensers, and then an approximately linear relationship between 90 and approaching 100% suppression. This near-linear portion of the profile includes both dispenser densities in which crop protection has been demonstrated, and densities in which it is unlikely. Suppression of males in pheromone traps was lost the next night after dispensers were removed, suggesting that the active ingredient was not persistent in the orchard environment. During most of the summer preharvest period, turning the dispensers off 1 or 2 h before the end of the predawn period of sexual activity provides the same amount of suppression of sexual communication as emission throughout the period of sexual activity. This suggests that encountering the pheromone from the mating disruption dispensers had a persistent effect on males. During the autumn postharvest period, only emission prior to midnight suppressed communication on nights on which the temperature fell below 19°C by midnight. These findings and the analysis will help manufacturers refine their offerings for mating disruption for this important California pest, and buyers of mating disruption to assess cost-effectiveness of competing offerings.

Airborne Pheromone Quantification in Treated Vineyards with Different Mating Disruption Dispensers against Lobesia botrana

Mating disruption (MD) is widely used against the European grapevine moth (EGVM), Lobesia botrana (Denis and Schiffermüller; Lepidoptera: Tortricidae), by installing passive dispensers or aerosol devices. The present work reports a new sampling and quantification methodology to obtain absolute data about field airborne pheromone concentration based on air samplings and sensitive chromatographic-spectroscopic methods. Samplings were performed in fields treated with passive dispensers or aerosol devices at different moments throughout the crop cycle to study how they act and how the disruption is triggered. Moreover, pheromone adsorption and releasing capacity of vine leaves were studied to elucidate their role in the disruption. Although both types of dispensers were effective in limiting the damage inflicted by EGVM, they performed differently and provided different airborne pheromone concentration profiles. Results also proved that leaves were able to adsorb and release part of the airborne pheromone acting as subsequent and additional pheromone sources. This fact could explain the different concentration profiles. Moreover, our results suggest that lower pheromone emission than that of the current passive dispensers still could provide an adequate performance in the field. Competitive mechanisms involved in MD using both dispensers, the dynamics of the airborne pheromone throughout the time and the importance of the canopy are discussed.

Pest Management and Ochratoxin A Contamination in Grapes: A Review

Ochratoxin A (OTA) is the most toxic member of ochratoxins, a group of toxic secondary metabolites produced by fungi. The most relevant species involved in OTA production in grapes is Aspergillus carbonarius. Berry infection by A. carbonarius is enhanced by damage to the skin caused by abiotic and biotic factors. Insect pests play a major role in European vineyards, and Lepidopteran species such as the European grapevine moth Lobesia botrana are undoubtedly crucial. New scenarios are also emerging due to the introduction and spread of allochthonous pests as well as climate change. Such pests may be involved in the dissemination of OTA producing fungi even if confirmation is still lacking and further studies are needed. An OTA predicting model is available, but it should be integrated with models aimed at forecasting L. botrana phenology and demography in order to improve model reliability.

Mating Disruption of Helicoverpa armigera (Lepidoptera: Noctuidae) on Processing Tomato: First Applications in Northern Italy

Helicoverpa armigera is a polyphagous and globally distributed pest. In Italy, this species causes severe damage on processing tomato. We compared the efficacy of mating disruption with a standard integrated pest management strategy (IPM) in a two-year experiment carried out in Northern Italy. Mating disruption registered a very high suppression of male captures (>95%) in both growing seasons. Geostatistical analysis of trap catches was shown to be a useful tool to estimate the efficacy of the technique through representation of the spatial pattern of captures. Lower fruit damage was recorded in mating disruption than in the untreated control plots, with a variable efficacy depending on season and sampling date. Mating disruption showed a higher efficacy than standard IPM in controlling H. armigera infestation in the second season experiment. Mating disruption showed the potential to optimize the H. armigera control. Geostatistical maps were suitable to draw the pheromone drift out of the pheromone-treated area in order to evaluate the efficacy of the technique and to detect the weak points in a pheromone treated field. Mating disruption and standard IPM against H. armigera were demonstrated to be only partially effective in comparison with the untreated plots because both strategies were not able to fully avoid fruit damage.