Grapevine Moth Research Articles

Climate change is likely to favour polyvoltine and invasive insect species, leading to more damage in the mid-latitude vineyards of Neuchatel

Climate change has major impacts on viticultural ecosystems worldwide, affecting wine production. Apart from direct impacts, the increase in temperature during the development season is likely to favour insect species, including polyvoltine ones, leading potentially to more damage in the vineyards. In this study, we examined the extent to which changes in mean temperature over the development season (March through September) can potentially increase the voltinism change the phenology and influence the reproduction of pest species in the vineyard area of Neuchatel (Switzerland). We first analysed long-term daily mean temperature data from 1970 to 2022 at the meteorological station of Neuchâtel. Then we used two climate scenarios (RCP4.5 and RCP8.5) to analyse daily mean temperature during the period 2023–2099. For both of these periods, we computed the number of growing degree days (GDDs) above 10 °C, as it is the base development temperature for many polyvoltine pest species. We then used specific bioclimatic models for two major pest species, namely the European grapevine moth (Lobesia botrana) and the American grapevine leafhopper (Scaphoideus titanus) to compare the current and future suitability of these two species to the air temperature conditions in Neuchâtel. Our results show an increase of about 425 GDDs since 1970 (+85 GDDs per decade). According to our models, values will continue to rise during the next decades, with a trend ranging from +28 GDDs per decade (RCP4.5) to +100 GDDs per decade (RCP8.5). This could lead to additional generations of polyvoltine pest species. A third annual generation can be expected in one year out of four for the European grapevine moth by the middle of the 21st century. While temperature conditions are currently moderately favourable for the American grapevine leafhopper, they are predicted to become highly favourable by the middle and the end of the century under both scenarios. These trends mean that climate change is likely to increase pest damage risks in the vineyards of Neuchatel in the future. Pest regulation will remain crucial in limiting major impacts on wine production.

Interaction between females and males grapevine moth Lobesia botrana modifies further mating preference

During reproduction, females may boost their fitness by being selective based on direct material benefits provided by the males, such as nuptial gifts. In Lepidoptera, male provides a spermatophore containing nutrients. However, virgin males produce a bigger spermatophore, containing spermatozoa and nutrients, allowing higher female fertility. Lepidoptera females that could detect the sexual status of males may thus prefer a male without previous mating experience (i.e. a virgin male). This mate selection could be achieved by the use of chemical indices, such as sexual pheromones and cuticular compounds, known to be possibly exchanged during reproduction, and which can be indicators of a previous mating experience and known to be possibly sources of information exchanged. In this study, we experimentally presented Lobesia botrana virgin males with females in order for them to be exposed to females’ natural sexual pheromones or cuticular compounds. 12 or 48 h after the exposure of males to either females’ sexual pheromones or cuticular compounds, these males were confronted to naïve females, which have a choice between them or a virgin non-exposed males. We highlighted that, despite producing a spermatophore of similar volume, all exposed virgin males were less likely to mate with females 12 h after exposure, while after 48 h of exposure this is only the case for virgin males exposed to sexual pheromones. L. botrana females may thus discriminate male sexual experience based on chemical cues (either from cues transferred directly from females to males, or from changes in the cuticular or pheromone males’ profile) indicating past mating experiences. Mating duration was longer for males exposed to sexual pheromones after 12 h only, and for males exposed to cuticular compounds after 48 h only. Pheromones signal might be more persistent over time and seems to more easily gather information for males. The physiological reasoning behind this result still needs to be investigated.

Analysis of insecticide resistance and de novo transcriptome assembly of resistance associated genes in the European grapevine moth, Lobesia botrana (Lepidoptera: Tortricidae).

The European grapevine moth Lobesia botrana (Denis & Shiffermüller 1776) is an economically important pest of the vine-growing areas worldwide. Chemical insecticides have been used for its control; however, its resistance status is largely unknown in many regions. We monitored the susceptibility of several L. botrana populations from Greece and Turkey. In addition, based on RNAseq transcriptome analysis, we identified and phylogenetically classify the cytochrome P450 genes of L. botrana, as well as analysed target site sequences and looked for the presence of known resistance mutations. Resistance against chlorantraniliprole, alpha-cypermethrin, spinetoram, etofenprox, and acetamiprid was very low (below 2.5-fold in all cases, compared to a reference strain from Greece) in all populations from Greece that were included in the study. However, resistance against indoxacarb (4-30-fold), spinosad (5-59-fold), and deltamethrin (18-30 fold) was detected in the L. botrana populations from Turkey, compared to a reference population from Turkey. De novo transcriptome assembly and manual annotation, and subsequent PCR-based analysis of insecticide target sequences (i.e. voltage-gated sodium channel - VGSC: target of pyrethroids and oxadiazines; nicotinic acetylcholine receptor subunit a6 - nAChR_α6: target of spinosad; ryanodine receptor - RyR: target of diamides; glutamate-gated chloride channel - GluCl: target of avermectins and; acetylcholinesterase - AChE: target of organophosphates) showed the absence of known resistance mutations in all specimens from both countries. Finally, the L. botrana CYPome (116 genes) was manually analysed and phylogenetically characterised, to provide resources for future studies that will aim the analysis of metabolic resistance.

Determination of Adult Population Fluctuation, Infection Rate of European Grapevine Moth [Lobesia botrana (Denis & Schiffermüller) (Lepidoptera: Tortricidae)] in the Vineyards of Hazro District (Diyarbakır)

Üzüm hem taze hem de kuru olarak insan beslenmesinde tüketilen önemli bir meyvedir. Bununla birlikte Türkiye ekonomisi için üzüm önemli bir ihraç ürünüdür. Bağlarda bitki koruma açısından birçok zararlı böcek ve hastalık etmeni bulunmaktadır. Bağ alanlarında çiçek ve salkımda beslenerek verim ve kaliteyi olumsuz etkileyen ana zararlı Salkım güvesi Lobesia botrana Denis & Schiffermüller (Lepidoptera: Tortricidae)’dir. Bu çalışma, mazruni üzüm çeşidinin yoğun olarak yetiştirildiği Diyarbakır ili Hazro ilçesinde bağlarında 2021-2022 yılları arasında her biri 10’ar dekar olan iki bağda eşeysel çekici tuzaklar kullanılarak yürütülmüştür. Bağlarda ana zararlı olan Salkım güvesi’nin erginlerinin doğaya ilk çıkış zamanı, ergin popülasyon değişimi, aktif olarak doğada bulunduğu süre, döl sayısı ile bağlardaki salkımların bulaşıklık oranının belirlenmesi amaçlanmıştır. Çalışma sonucunda L. botrana ergin eşeysel çekici tuzaklarda ilk olarak 18 Nisan tarihinde ve erginlerin son olarak ta 14 Kasım tarihinde tespit edilmiştir. L. botrana ergin uçuşlarının bağ alanlarında yaklaşık 8 ay süreyle doğada aktif oldukları saptanmıştır. Zararlının 2021 yılında Hürriyet mahallesinde toplam 296 ergin/tuzak sayılmış olup, en fazla haftalık popülasyon yoğunluğu 21 Ekim (21 ergin/tuzak), Yazgı mahallesinde ise toplam 1844 ergin/tuzak sayılmış olup, en fazla haftalık popülasyon yoğunluğu 8 Temmuz (198 ergin/tuzak) tarihinde tespit edilmiştir. 2022 yılında ise, Hürriyet mahallesinde toplam 663 ergin/tuzak sayılmış olup, en fazla haftalık popülasyon yoğunluğu 27 Haziran (80 ergin/tuzak), Yazgı mahallesinde ise toplam 2055 ergin/tuzak sayılmış olup, en fazla haftalık popülasyon yoğunluğu 20 Haziran (233 ergin/tuzak) tarihinde tespit edilmiştir. Popülasyon yoğunluğuna bağlı olarak zararlının bölgede hasattan önce 3, hasat sonrası ise 1 olmak üzere yılda 4 tepe noktasını oluşturduğu ve doğa şartlarında tahmini olarak 4 döl verebildiği belirlenmiştir. Hürriyet mahallesindeki bağda salkımların zararlı ile bulaşık oranının yıllara göre sırasıyla %5 ve %23, Yazgı mahallesindeki bağda ise salkımların zararlı ile bulaşık oranının yıllara göre sırasıyla %25 ve %45 oranında olduğu tespit edilmiştir.

Sex pheromone autodetection by Lobesia botrana females (Lepidoptera: Tortricidae)

Pheromone-based technologies, such as mating disruption or pheromone-baited traps have been widely used to protect vineyards against the European grapevine moth, Lobesia botrana (Lepidoptera: Tortricidae), an insect pest with major economic impact on the viticulture industry. So far, research and development of such techniques has predominantly focused on how male insects respond to the sex pheromone emitted from calling females, while female autodetection (i.e., the ability of females to detect their sex pheromone) has, for the most part, been overlooked. As a result, any potential effects of pheromone-mediated strategies due to female autodetection are poorly understood. In this work, we investigated the olfactory and behavioural response of L. botrana virgin and mated females to the major component of their conspecific sex pheromone (E7,Z9–12:OAc) through electroantennographic and two-choice olfactometric assays. The results confirm that both virgin and mated females respond at antennal level to their own pheromone and subsequent behavioural results revealed a strong repellent effect of female L. botrana to synthetic pheromone which was stronger in the case of mated females. Thus, the findings on sex pheromone autodetection by L. botrana females may contribute to designing better pheromone-mediated strategies for its biological control in vineyards. The suggested approach based on our findings is that of a dispersal behaviour: a) in order to avoid competition from other conspecific calling females and b) as a spacing strategy among host plant resources to ensure progeny survival.

Adult Population Dynamics of the European Grapevine Moth [Lobesia botrana Denis & Schiffermüller (Lepidoptera: Tortricidae)] in Midyat Vineyards

The study was conducted to determine the adult population change, the period when they are active in nature, and the number of generations of the European grapevine moth, Lobesia botrana [Denis & Schiffermüller (Lepidoptera: Tortricidae)]. The study was carried out in vineyards having the Mazruni variety (unregistered), which is the most common grape in Midyat district of Mardin province, between 2014 and 2015. The results indicated that adults of the moths were first encountered in the pheromone traps in early April, and the pest population was high in both years (an average of 2173 adults/traps in 2014 and 1615 adults/traps in 2015). According to the results, the pest gives three generations, and three or four peaks (three main peaks during the season and a low peak at the end of the season) occur in the vegetation period of grapes. These peaks coincide with the flowering period (May 8-16), the berry (chickpea size) period (June 27-July 6), the sweetening period of the grains (July 27-August 15), and the sweetening-harvest period (September 17-19), respectively. The pest remains active in vineyards for approximately seven months, thereafter overwinters between late October and early November. The results obtained provide essential information that helps pest control at the appropriate time.

Determination of Trichogramma euproctidis efficacy against the key pest, European grapevine moth, Lobesia botrana (Lepidoptera: Tortricidae) in the Aegean region vineyards, Turkey

European grapevine moth Lobesia botrana is the most important pest causing crop losses in most of Türkiye’s grape growing regions, feeding mainly on inflorescence and grape berries. This study was carried out to determine the release efficiency and the most efficient dose of the native egg parasitoid, Trichogramma euproctidis against L. botrana in an organic vineyard located in the Menemen district of Izmir, in the Aegean Region, which has the largest grape production area. In this context, two different release doses at 75 000 and 100 000 parasitoids/ha were applied to find the most effective one. The effectiveness of the parasitoid was compared in terms of pest infestation rates in grape bunches from parasitoid-released and non-released plots just prior to harvest. The infestation rates in plots released 100 000 parasitoids/ha (12, 4 and 5 %) and 75 000 parasitoids/ha (7.5, 11 and 1 1 %) were lower than control (25, 33 and 70 %) in 2017, 2018 and 2019, respectively. In 2018 and 2019, the high release dose (100 000 parasitoids/ha) applied five or six times in total was the most promising with the lowest pest infestation rates. In this study, the most effective release dose (100 000 parasitoids/ha) of the native egg parasitoid, T. euproctidis, was determined for the first time in Türkiye. In conclusion, the results obtained from the study will encourage the use of this parasitoid in organic and integrated grape growing programs.

Influence of Grapevine Cultivar on Population Levels of Lobesia botrana (Lepidoptera: Tortricidae) and Effectiveness of Insecticides in Controlling This Pest

The European grapevine moth, Lobesia botrana (Denis and Schiffermüller) (Lepidoptera: Tortricidae), is the most critical pest of vineyards. In the present study, pheromone-baited traps were applied in 2021 and 2022 to monitor the moth population dynamics and to determine the number of L. botrana generations. The number of eggs and larvae was also counted in four vineyards with Askari, Yaghooti, Keshmeshi, and Fakhri cultivars. Moreover, the morphological properties of clusters were evaluated in different grape cultivars to find out the susceptible cultivar to L. botrana. In 2022, different insecticides were used in the Askari cultivar vineyard, and larval damage level was assessed. Three generations were recorded in all vineyards each year. The population of males was not affected by the cultivar. In contrast, the population density of eggs and larvae was significantly higher in Yaghooti than in other tested cultivars. It could be attributed to the cluster compactness and thin skin of berries in Yaghooti, which makes it more susceptible to L. botrana infestations. In contrast, the lowest eggs and larval population density was reported in the Fakhri cultivar indicating the tolerance of this cultivar compared to the other tested cultivars. The field trial showed that the application of insecticides in the second and third generations reduced the damage level of L. botrana. The rotation of insecticides with different modes of action in consecutive generations of L. botrana can be used to reduce damage levels.

Grapevine plant defense responses associated with arthropod herbivory: A review

Grapes are among the most valuable fruit crops with over ∼80 billion US dollars in farm gate value worldwide. Many insect pests, including phylloxera, mealybugs, grapevine moths, and spotted lanternfly, among others, persistently challenge grapevine plants. Insect infestations can limit berry production and affect the quality and quantity of its several byproducts, resulting in economic losses. To counter insect attack, grapevines employ different mechanisms, including structural, direct, indirect, and inducible defenses. Surprisingly, there is a lack of literature review in the grapevine-arthropod interactions study system. This review summarizes various defense mechanisms, including primary/secondary metabolites, elicitors, volatile organic compounds, etc., used by grapevines against insect and mite attacks that would help to improve and develop pest management strategies in vineyards. Finally, future perspectives of grapevine-insect interactions will be discussed, which could help to reveal novel grapevine defense mechanisms against arthropod herbivory and develop new pest management strategies to reduce crop losses.

ОБ ЭФФЕКТИВНОСТИ ПРИРОДНОЙ ПОПУЛЯЦИИ ПАРАЗИТОИДА ГРОЗДЕВОЙ ЛИСТОВЕРТКИ BASSUS TUMIDULUS (NEES, 1812) (HYM.: BRACONIDAE) НА ТАМАНСКОМ ПОЛУОСТРОВЕ

The paper presents the results of studies of trophic relationships of Lobesia botrana Den. et Schiff. (Lepidoptera, Torticidae) in the «parasitoid - insect-host» system in ampelocenoses. For the first time for the Anapa-Taman viticulture zone of the Krasnodar region, the species Bassus tumidulus (Nees, 1812) (Microdus tumidulus (Nees von Esenbeck, 1812), Therophilus tumidulus (Nees von Esenbeck, 1812) was established as a mass natural enemy of the European grape moth in the conditions of industrial plantings of grapes. During the observation period (2021-2023), this type of parasitoid was the most common in terms of the number of infected specimens of L. botrana, its frequency of occurrence exceeded that of other parasitoids recorded in these studies by 2.7 times. There is a lack of knowledge of the parasitoid fauna in the consortia formed around the European grape moth in ampelocenoses. Knowledge of trophic relationships of the main economically significant pest of the vineyards of the Anapa-Taman zone of the Krasnodar region as a mechanism for regulating its abundance can help in the development of effective biologized protection measures in the fight against it. According to the results of extirpation, the seasonal dynamics of the flight of the adult parasitoid was revealed and compared with the life cycle of the harmful lepidopteran host. A complete adaptation of Bassus tumidulus to the target phases of the development of the European grape moth has been established. The conclusion is made about the specialization of the polyphage to this pest in the region. The characteristic features of Bassus tumidulus population dynamics were revealed, namely, an increase in the density of the hymenoptera population in ampelocenosis by the end of the growing season. The data of the biology of Bassus tumidulus, given in the literature, have been confirmed.

The effects of temperature on pathogenicity of entomopathogenic fungi for controlling larval populations of the European grapevine moth (Lobesia botrana) (Lepidoptera: Tortricidae)

The European grapevine moth (Lobesia botrana) is currently the most damaging pest in many viticultural regions of South and Central Europe and is highly responsible for the development of secondary infections by Botrytis cinerea to both table and wine grapes. Entomopathogenic fungi (EPF) are considered as substantial biological control agents of insect pests. However, they are able to infect their hosts only under a narrow spectrum of environmental conditions. In this study, the effects of temperature on pathogenicity of EPF for the control of L. botrana are reported. Among a collection of 33 EPF isolates, six virulent isolates were selected for the experiments. The bioassays took place at controlled conditions, under the temperature regimes of 20, 22.5, 25, 27.5, 30, and 32.5 °C. A conidial concentration of 1 × 108 conidia/ml was prepared for each isolate, and fungi were applied by spraying them on third-instar larvae (L3) of L. botrana. Both factors, fungal isolate and temperature, significantly affected mortality of L. botrana. Most fungal isolates exhibited their highest larval mortality rates seven days post-treatment at the temperatures of 25 and 27.5 °C. Some isolates caused considerably high larval mortality that exceeded 90% under specific temperature conditions. Overall, EPF showed great potential as bio-control agents for controlling larval populations of L. botrana.

The Influence of Groves on Aboveground Arthropod Diversity and Evolution in a Vineyard in Southern Romania

This paper investigates the biodiversity of adult arthropods in two grapevine plantations influenced by two adjacent groves over a three-year period (2020–2022) in the viticultural center of Stefănești Argeș, located in southern Romania. The study holds significant implications for introducing parasitoid/predatory insect species into vineyards to control grapevine pests. A total of 164 arthropod species were identified, including 27 beneficial species. Additionally, two moth species, Lobesia botrana and Sparganothis pilleriana, were identified. L. botrana was consistently observed throughout the study, while S. pilleriana was only observed in 2022. The research reveals that the location with the highest number of identified species was in a grove near a black field, with 103 species. Other areas with notable species diversity included a vineyard maintained as a black field (89 species), a grove near permanent natural grassland (88 species), and a vineyard with intervals between rows of grapevines maintained as natural permanent grassland (81 species). Introducing beneficial organisms, such as the predator Crysoperla carnea, is recommended to control grapevine moths in this ecosystem.

Toxicity of Pesticides Applied in European Vineyards on Anagyrus vladimiri and Trichogramma evanescens, Parasitoids of Planococcus ficus and Lobesia botrana.

Risk assessments of chemical pesticides toward natural enemies are crucial for ensuring sustainable grapevine-integrated pest management. In this context, laboratory experiments were conducted to evaluate the toxicity of four insecticides (lambda-cyhalothrin, flupyradifurone, acetamiprid, and cyantraniliprole) and one fungicide (spiroxamine) commonly applied in German (European) vineyards on the pupae and adults of both Anagyrus vladimiri, a parasitoid of the vine mealybug Planococcus ficus, and Trichogramma evanescens, a parasitoid of the European grapevine moth, Lobesia botrana. The tested pesticides did not significantly affect the development of the pupal stage inside mealybug mummies or the emergence of the parasitoid A. vladimiri. The pesticides flupyradifurone, acetamiprid, and spiroxamine resulted in the highest mortality percentages for all emerged A. vladimiri parasitoids at 8 and 10 days after treatment compared with either in lambda-cyhalothrin or cyantraniliprole. However, all pesticides, except the diamide insecticide cyantraniliprole, significantly affected the development of the pupal stage and the emergence of the parasitoid T. evanescens. The percentages of T. evanescens emergence following the application of the fungicide spiroxamine or either lambda-cyhalothrin or flupyradifurone were significantly higher than those observed in the acetamiprid treatment. Regarding direct contact toxicity, the highest percentages (100%) of A. vladimiri adult parasitoid mortality were obtained in the flupyradifurone, acetamiprid, and spiroxamine treatments, while the lowest mortality percentages were observed in lambda-cyhalothrin, cyantraniliprole, and untreated control treatments. According to the IOBC classes of toxicity, flupyradifurone, acetamiprid, and spiroxamine were classified as harmful, while both lambda-cyhalothrin and cyantraniliprole were classified as slightly harmful to A. vladimiri adults. As such, all pesticides had a significant impact on the survival of exposed T. evanescens adults. The highest percentages of adult T. evanescens mortality were obtained in the flupyradifurone, acetamiprid, and spiroxamine treatments, with the fungicide spiroxamine resulting in significantly higher mortality percentages than either flupyradifurone or acetamiprid, while the lowest mortality percentages were found in the lambda-cyhalothrin and cyantraniliprole treatments. Therefore, applying the insecticides acetamiprid and/or flupyradifurone and the fungicide spiroxamine should be avoided when A. vladimiri and/or T. evanescens are naturally present or released in grapes. The insights gained from these two easy-to-rear parasitoid species allow analogous conclusions to be drawn for closely related species in vineyards belonging to either family Encyrtidae or Trichogrammatidae, which are not easy to rear. Interestingly, using the safer insecticides lambda-cyhalothrin and/or cyantraniliprole could be compatible with both parasitoid species, which could be sustainably exploited in either conservation or augmentative biological control in vineyards.

Environmentally Friendly Strategies for Controlling the European Grapevine Moth, Lobesia botrana (Lepidoptera: Tortricidae)

Terlemezyan, H., M. Sargsyan, H. Harutyunyan, S. Sargsyan and N. Zarikian. 2023. Environmentally Friendly Strategies for Controlling the European Grapevine Moth, Lobesia botrana (Lepidoptera: Tortricidae). Arab Journal of Plant Protection, 41(3): 272-277. https://doi.org/10.22268/AJPP-041.3.272277 The European grapevine moth, Lobesia botrana (Denis & Schiffermüller, 1775) (Lepidoptera: Tortricidae), a palearctic pest, has been the target of an international control campaign. Agricultural production areas in Armenia were identified as lacking effective control in 2019- 2020. The results of using a mixture of bacterial and chemical insecticides (BTTER-55 + Coragen, BTTER-94 + Coragen) were effective in controlling this pest. Coragen combined with sublethal concentration of bacterial insecticides (BTTER-55 + Coragen, BTTER-94 + Coragen) showed high biological efficiency against young larvae of grapevine moth under vineyard conditions. It has been proven also that, Coragen together with the applied insecticides that fell on the soil after spraying were less dangerous ecologically since they reduced the number of soil-living ammonifiers for only a short period (1-2 months). In addition, results obtained confirmed that the bacterial insecticides BTTER-55 and BTTER-94 differed in morphological and physiological features, particularly in the size of vegetative cells and spores formed by them, as well as in the size of insecticidal crystalline bodies, colonies shape and assimilation of carbon and nitrogen sources. Keywords: Armenia, European grapevine moth, insecticide, Invasive pests, Plant protection.

A review of history and geographical distribution of grapevine moths in Italian vineyards in light of climate change: Looking backward to face the future

Tortricid and pyralid moths include important pests of vineyards. This review offers a retrospective analysis of the geographic distribution expansion of the European grapevine moth, Lobesia botrana (Denis & Schiffermüller) (Lepidoptera: Tortricidae) and the replacement or marginalization of the importance of the previously largely vine-infesting species, i.e., Sparganothis pilleriana (Denis & Schiffermüller) and Eupoecilia ambiguella (Hübner), because of the combination and interaction between climate change, invasive alien species, and new cultivation techniques. Herein, we have focused on the case study of Italy, which is currently representing the fourth largest country in the world in terms of cultivated wine-growing area, and the biggest producer of wine grapes, as a model to analyze the possible influence of climate change on the occurrence and harmfulness of grapevine moths and what will be the next challenges for their sustainable management. Starting from the retrospective analysis and learned lessons, a research agenda outlining future challenges for IPM of grapevine moth pests in Mediterranean countries is developed.

Assessing the risk of invasion by a vineyard moth pest guild

Biological invasions are most effectively managed when identified in their early stages, which often hinges on robust surveillance programs. The recent invasion of the European grapevine moth (Lobesia botrana) in California suggests that viticultural areas in the western United States may face severe economic consequences from this and other Tortricid and Pyralid moth species if they were to establish. To gain insights into the risk these grapevine pests pose, we used occurrence records for L. botrana and four other moths native to Europe or the eastern United States and selected environmental variables to predict the extent of climatically suitable areas and potential pest co-occurrence along the West Coast of the United States. A suite of models was generated using MaxEnt with species-specific tuning of model settings. Overall, the results confirmed high suitability for L. botrana to establish across much of the study region, driven largely by high monthly variability in precipitation and low elevation. Two species were predicted to have intermediate suitability to establish over the study region (i.e., grape tortrix moth, Argyrotaenia ljungiana; grape berry moth, Paralobesia viteana), while two others had low suitability (i.e., European grape berry moth, Eupoecilia ambiguella; Christmas berry webworm, Cryptoblabes gnidiella). The highest predicted potential for co-occurrence was between L. botrana and P. viteana, accounting for 19% of the total viticulture area, followed by L. botrana and A. ljungiana for 11% of the study area. These results may help with the optimization of surveillance efforts by indicating which species or areas should be prioritized for the deployment of invasive pest detection programs with pheromone traps. Indeed, given the apparent potential for co-occurrence of multiple moth pests in certain areas, our results may inform where single or multi-lure traps should be deployed as a more cost-efficient monitoring tool.

European grapevine moth, Lobesia botrana Part I: Biology and ecology

European grapevine moth, Lobesia botrana Part I: Biology and ecology

European grapevine moth, Lobesia botrana Part II: Prevention and management

European grapevine moth, Lobesia botrana Part II: Prevention and management

Temperatures during the development season are increasingly favourable for polyvoltine pest species in Switzerland

With global warming, the mean temperature during the insect development season has been increasing in Switzerland over the last decades, and this trend is predicted to continue. As a result, the annual number of generations could increase for polyvoltine insect species. Some pest species, such as the box tree moth (Cydalima perspectalis), the grapevine moth (Lobesia botrana), the codling moth (Cydia pomonella), and the Comstock mealybug (Pseudococcus comstocki), are therefore likely to produce more generations in the future, leading to more damage to forests, vineyards and crops. These species all have a base development temperature (tb) of around 10 °C. In this study, we examined the extent to which changes in daily mean temperature (Tmean) averaged over the development season (April through September) could potentially increase the voltinism of these species in various regions of Switzerland. We analysed long-term daily Tmean data from the period 1980–2021 at 67 meteorological stations covering an elevation range from 203 to 2283 m a.s.l. We then used two climate scenarios (RCP2.6 and RCP8.5) to analyse daily Tmean during the period 2022–2099. We computed growing degree days (GDDs) above tb = 10 °C and looked at the trends across elevation. Our results show that daily Tmean averaged across the development season increased more than the daily Tmean averaged over the entire year over the last 40 years. There was an average increase of 60 GDDs per decade during this period, with larger increases occurring at lower elevations. Our results indicate that by the end of the 21st century there could be more GDDs on the Swiss Plateau than currently occur at lower elevations on the southern side of the Alps and that the number of GDDs currently occurring on the Swiss Plateau could be found at middle elevations (800–1400 m a.s.l.). Future temperature conditions can thus be expected to favour additional generations of pests annually at lower elevations and to allow them to complete a full single cycle per year at higher elevations.

Mathematical modeling of pest resistance to insecticides in a heterogeneous environment

Insecticides are an effective tool for controlling grapevine moths such as Lobesia botrana. However, when massive use of insecticides, pests develop resistance because of selection of resistant individuals of the population and/or because of natural mutation. The main question is then to define a strategic pest management with respect to time and space. In the first part of this work, we present a model without spatial structure describing the dynamics of insects including its resistance to insecticides. In the second part, we include in the model dispersal between different space patches. Individuals can move from one patch to another at a fast time scale with respect to the demographical time scale. Using this model, we aim to understand the main characteristics leading to persistence or extinction of the insect pest population. We establish global stability results. Numerical simulations provide some interesting insights on the dynamics of the pest population.