European Grapevine Moth Lobesia Botrana Research Articles

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 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.

Mating still disrupted: Future elevated CO<sub>2</sub> concentrations are likely to not interfere with <i>Lobesia botrana</i> and <i>Eupoecilia ambiguella</i> mating disruption in vineyards in the near future

The successful, area-wide application of the mating disruption (MD) technique, an insect sex pheromone-based biotechnological pest control method, against the European grapevine moth Lobesia botrana and the European grape berry moth Eupoecilia ambiguella, has led to drastic reductions in insecticide application in vineyards. However, since insect pheromone perception and emission can be affected by abiotic conditions, the future success of MD may be affected by climate change. At the same time, politics and society are calling for drastic and sustainable reductions in pesticide application, making highly specific, efficient, and environmentally friendly pest control techniques like MD more important than ever. To anticipate whether climate change factors will interfere with the MD of L. botrana and E. ambiguella in vineyards, we conducted field experiments in the Geisenheim VineyardFACE (Free-Air Carbon dioxide Enrichment) facility. The insects were raised at ambient or elevated temperatures in the lab and male moths were released in cages installed in the VineyardFACE facility. Trap recapture rates obtained by pheromone lures or female moths under elevated or ambient CO2 in areas with and without MD were evaluated. Our results did not indicate a reduced efficacy ofL. botrana or E. ambiguella MD at elevated CO2 concentrations, irrespective of the temperature the moths were raised under. From a practical point of view—and especially from an ecological one—our results are good news. They indicate that MD will not be negatively affected by future elevated CO2 concentrations.

Mating Competitiveness of Irradiated Lobesia botrana (Lepidoptera: Tortricidae) in Male-Only and Both Sex Release Strategies under Laboratory Cage Conditions

This laboratory study explored the concept of whether irradiated male-only releases are more or equally efficient as releases of both irradiated males and females in the context of using the sterile insect technique/inherited sterility (SIT/IS) for the management of the European grapevine moth Lobesia botrana. The current study examined the mating competitiveness of 150-Gy-treated L. botrana male and female moths or 150-Gy-treated male moths only, with untreated moths in laboratory cages. Our results showed that the release of both sexes significantly increased the competitiveness value (C) and the biological efficiency index (BE) as compared with male-only release, and this was independent of the male to untreated male ratio. Moreover, a single release of 150-Gy-treated and untreated males and females at a 1:1:10:10 ratio (untreated male:untreated female: treated male:treated female) significantly reduced egg hatch, and the number of first-generation offspring (F1) was small. The emergence of F2-moths per untreated F1 male and female moth was low, but these undesired fertile moths should be eliminated in order to achieve effective control. The results presented herein provide useful information on the impact of 150-Gy-treated male-only, versus releases of both treated males and females on untreated moths, which is essential to managing L. botrana populations with SIT/IS.

Dissipation kinetics of some pesticides applied singly or in mixtures in/on grape leaf.

Grape and leaf quality are often severely reduced by fungi such as grey rot Botrytis cinerea Pers., powdery mildew Erysiphe necator Schwein, and downy mildew Plasmopara viticola (Berk. & M.A.Curtis) Berl. & De Toni and by insects such as Otiorhynchus spp., European grapevine moth Lobesia botrana Den.-Schiff., vine mealybug Planococcus citri Risso, and grape erineum mite Colomerus vitis Pgst. Various pesticides are often applied to mitigate these pest problems. These chemicals used singly as well as in the form of a mixture can leave residues on or in the crop. It is therefore of great importance to study the dissipation of the pesticides applied alone and in mixtures to this crop to protect consumers. The dissipation kinetics of cypermethrin, boscalid, deltamethrin, kresoxim-methyl, lambda-cyhalothrin, metalaxyl-M, metrafenone, and triadimenol residues were studied in vine leaves grown under sunny conditions in Turkey. The dissipation rate for singly applied pesticides followed first-order kinetics, with half-lifes in grape leaves in the range of 1.85-7.22 days. Changes in the degradation process of pesticide residues were determined after application, as both single applications and mixtures. The degradation of boscalid, cymoxanil, deltamethrin and metalaxyl-M accelerated while the degradation of cypermethrin, kresoxim-methyl, and lambda-cyhalothrin slowed down in mixtures of pesticides. The use of pesticides in mixtures leads to slower degradation and higher residues for some active ingredients and faster degradation and fewer residues for other active ingredients. Therefore, pesticide mixtures should not be applied in the field without having detailed information about their ingredients. © 2022 Society of Chemical Industry.

Investigation of flight activity and damage status of European grapevine moth Lobesia botrana (Denis & Schiffermuller) (Lepidoptera: Tortricidae)

The present study was conducted in Ankara province on a grape variety called Kalecik karası in vineyards between 2013-2014. It’s aimed to determine biological criteria such as Lobesia botrana (Denis & Schiffermuller, 1775) Lep .: Tortricidae]'s adult flight activity, the duration of its presence in nature and the number of generation, which is essential for the control, as well as the damage status. As a result of the study, it was determined that the first adults of L. botrana were caught in April and the first peak of the pest was seen in the last week of April in both years. It was observed that the second peak of the pest occured in the second-third week of June and it produced two generations per year. It was determined that the flight of adults ended in September. European grapevine moth adults were found to be active for about six months. In both years, during the control and counting for vegetation and harvest period, although there were European grapevine moths in the vineyard where Kalecik karası grape variety was harvested, there were not any eggs and larvae and there was not any damage on vines during harvest.

Exploring the Use of Entomopathogenic Nematodes and the Natural Products Derived from Their Symbiotic Bacteria to Control the Grapevine Moth, Lobesia botrana (Lepidoptera: Tortricidae).

Simple SummaryThe European grapevine moth (EGVM) Lobesia botrana (Lepidoptera: Tortricidae) attacks vineyards in Europe, the Middle East, and North and South America. Global movement toward sustainable agriculture urges the development of environmentally friendly tools that can replace traditional pesticides. Entomopathogenic nematodes (EPNs) are well-known biological control agents against various arthropod pests. The EPNs act together with symbiotic bacteria that produce natural products with insecticidal potential. Novel formulations and application technology allow their application against aerial pests, including those associated with vineyards. This study investigated the viability of four EPN species and their corresponding bacteria derivates (unfiltered ferment, UF, or cell-free supernatant, CFS) against EGVM (larval and pupa instars). The results revealed that all EPN species killed various EGVM larval stages. Killing pupae required a higher number of IJs than controlling larvae. Steinernema carpocapsae registered the most promising results, killing ~50% L1 and >75% L3/L5 in 2 days. The use of the bacterial bioactive compounds achieved similar results, with UF registering higher activity than CFS. Overall, we demonstrated that both EPN and bacterial bioproducts have a great potential to control EGVM in sustainable viticulture. Further research in co-formulation with adjuvants is required to ensure their survival in the aboveground grapevine areas. The European grapevine moth (EGVM) Lobesia botrana (Lepidoptera: Tortricidae) is a relevant pest in the Palearctic region vineyards and is present in the Americas. Their management using biological control agents and environmentally friendly biotechnical tools would reduce intensive pesticide use. The entomopathogenic nematodes (EPNs) in the families Steinernematidae and Heterorhabditidae are well-known virulent agents against arthropod pests thanks to symbiotic bacteria in the genera Xenorhabdus and Photorhabdus (respectively) that produce natural products with insecticidal potential. Novel technological advances allow field applications of EPNs and those bioactive compounds as powerful bio-tools against aerial insect pests. This study aimed to determine the viability of four EPN species (Steinernema feltiae, S. carpocapsae, S. riojaense, and Heterorhabditis bacteriophora) as biological control agents against EGVM larval instars (L1, L3, and L5) and pupae. Additionally, the bioactive compounds from their four symbiotic bacteria (Xenorhabdus bovienii, X. nematophila, X. kozodoii, and Photorhabdus laumondii subsp. laumondii, respectively) were tested as unfiltered ferment (UF) and cell-free supernatant (CFS) against the EGVM larval instars L1 and L3. All of the EPN species showed the capability of killing EGVM during the larval and pupal stages, particularly S. carpocapsae (mortalities of ~50% for L1 and >75% for L3 and L5 in only two days), followed by efficacy by S. feltiae. Similarly, the bacterial bioactive compounds produced higher larval mortality at three days against L1 (>90%) than L3 (~50%), making the application of UF more virulent than the application of CFS. Our findings indicate that both steinernematid species and their symbiotic bacterial bioactive compounds could be considered for a novel agro-technological approach to control L. botrana in vineyards. Further research into co-formulation with adjuvants is required to expand their viability when implemented for aboveground grapevine application.

Additive and synergistic interactions of entomopathogenic fungi with Bacillus thuringiensis for the control of the European grapevine moth Lobesia botrana (Denis and Schifferm\xfcller) (Lepidoptera: Tortricidae)

BackgroundThe European grapevine moth, Lobesia botrana (Denis and Schiffermüller) (Lepidoptera: Tortricidae) is currently the most damaging pest in many viticultural regions across the Mediterranean basin and elsewhere. Its feeding activity also enhances the development of secondary infections by Botrytis cinerea - and other fungi - to wine grapes. The gram-positive bacterium Bacillus thuringiensis (Bt) has been reported to partially control larval populations of L. botrana, while it requires to be digested by the insect to cause infection. Entomopathogenic fungi (EPF) are possibly capable of acting synergistically with Bt to increase its efficacy against insect pests.ResultsThe hypothesis of synergy or antagonism between Bt and EPF for the control of L. botrana was tested in two bioassays: A) Insects fed on Bt diet and subsequently some groups were sprayed by conidia of Beauveria bassiana or Paecilomyces fumosoroseus, and B) Grapes were sprayed by Bt, or B. bassiana, or combination of the two, and then untreated insects were placed to feed on the grapes. In both bioassays, combination treatments performed better than single treatments, indicating additive action or synergy. The Bt and B. bassiana combination treatment (Bt diet for 30 h and then sprayed with conidia of B. bassiana) resulted in 91% larval mortality while the single Bt and B. bassiana treatments caused 28% and 34% mortality respectively. Such results indicated synergism. Combination treatment on grapes also caused significantly higher mortality on L. botrana larvae, compared to single treatments. The median lethal time (LT50) was estimated as 8.43 days for the single Bt treatment, 7.87 days for the single B. bassiana treatment and 6.3 days for the combination Bt + B. bassiana treatment.ConclusionsAbsence of antagonism as well as additive action or synergy were indicated by the results. Larval populations of the pest can be effectively controlled by using microbial biocontrol agents. Further research is needed to investigate the biotic and abiotic factors that affect interactions between insect hosts and entomopathogenic organisms. However, the entomopathogens used in the present study showed remarkable action and may be included parallelly in control strategies against vineyard pests.

Side Effects of Sulfur Dust on the European Grapevine Moth Lobesia botrana and the Predatory Mite Kampimodromus aberrans in Vineyards

Simple SummaryThe European grapevine moth Lobesia botrana is the most important carpophagous pest in European vineyards. Synthetic insecticides are usually applied for moth control, but their impact on human health and environmental quality requires a reduction in their usage. The exploitation of the side effects of inorganic fungicides of natural origin repeatedly used during the growing season can contribute to achieve this goal. In this study, a possible effect on L. botrana infestation of sulfur dust applied to control powdery mildew is tested under laboratory and field conditions. Sulfur dust reduced egg laying by around 80% in both laboratory and field bioassays. In the laboratory, the product showed a slight contact toxicity on eggs and reduced larval settlement. A single field application of sulfur dust during L. botrana egg laying reduced larval infestation by approximately 40%. No adverse effects were observed on the predatory phytoseiid mite Kampimodromus aberrans.To reduce the impact of synthetic insecticides on human health and the environment, eco-friendly alternatives must be investigated. Knowledge of the side effects on pests and natural enemies of natural products applied to vineyards is very useful. Sulfur dust, which is used in vineyards to control powdery mildew, is investigated in laboratory and field bioassays for its effects on Lobesia botrana egg laying, egg hatching, and larval settlement. In field trials, the efficacy of sulfur dust against the two L. botrana carpophagous generations is compared with that of Bacillus thuringiensis and kaolin, and its side effects on the phytoseiid mite Kampimodromus aberrans are evaluated. In the bioassays, sulfur dust reduced female survival by 43%, egg laying by around 80%, egg hatching by 10%, and larval settlement by 55%. In field trials, sulfur dust caused a significant decrease in the number of L. botrana larval nests of both generations, even though the efficacy was lower than that of B. thuringiensis. No negative effects of sulfur dust on the predatory mite population density was observed. On the basis of these results, in the context of Integrated Pest Management strategies in vineyards, the activity of sulfur dust against L. botrana could be exploited by timing its application to the beginning of egg laying.

Tachinid (Diptera, Tachinidae) parasitoids of Lobesia botrana (Denis & Schiffermüller, 1775) (Lepidoptera, Tortricidae) and other moths.

The present paper reports data on the biology of eleven species of tachinid flies collected in Italy and Spain on different host plants and emerged from different host larvae. An annotated list of the eleven species emerged from the collected lepidopterans is provided; information about distribution and biology are given as well as the description of their puparia. Two new parasitoid species of the European Grapevine Moth (EGVM) Lobesia botrana were recorded: Clemelis massilia, whose host preferences were unknown so far, and Neoplectops pomonellae. A list of lepidopteran pest species with their associated plants and tachinid parasitoids is then given in order to highlight the relationships among the three components of the biocenosis (plant, herbivore and parasitoid). Eventually, due to the great economic importance of L. botrana in viticulture, a preliminary identification key to the puparia of its tachinid parasitoids is provided.

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.

A novel version of the Von Foerster equation to describe poikilothermic organisms including physiological age and reproduction rate

The mathematical description of poikilothermic organisms’ life cycle, of insects in particular, is a widely discussed argument, above all for its application in decision support systems. The increasing interest among agricultural industries in obtaining products with minor quantities of chemical inputs has led entomologists and model scientists to study in greater depth not only the biology and behaviour of the insects, but also the way to translate these mechanisms into mathematical language. The aim of this work is to provide a new instrument to describe insect pests’ population density. In particular, the study analyses insects’ development through the life stages driven by environmental factors. This has led researchers to consider physiological age, instead of the more widely used chronological age. In addition to mortality and fertility rates, the possibility of improving the simulation by inserting as a boundary condition results from previous field monitoring or the links with diapause models has been considered. The work is validated in the case of the European grapevine moth Lobesia botrana.

Reproductive performance of the European grapevine moth Lobesia botrana (Tortricidae) is adversely affected by warming scenario

The European grapevine moth, Lobesia botrana (Denis and Schiffermuller), is an important grape pest worldwide. To forecast how this species might respond to climate change has emerged as one major challenge in recent viticultural research. Predictions about L. botrana population dynamics under global warming scenario are usually derived from physiologically based demographic models (PBDMs). Despite their ecological realism, PBDMs are based on physiological equations derived from constant, unrealistic thermal regimes, and they exclude the effects of temperature on male’s reproductive traits, which importantly mediates population dynamics in this species. Focused on Burgundy (a viticultural region of France), we compared the adult performance of L. botrana between the Current Fluctuating Regime (CFR) based on in situ meteorological data and the Future Fluctuating Regime (FFR) based on the outputs of climate models. Under controlled conditions complying to the scenario of local warming termed FFR, L. botrana individuals incurred reduced adult lifespan, while their body amounts of four major energetic components (proteins, lipids, glycogen, soluble carbohydrates) remained unchanged compared to individuals exposed to the CFR. Furthermore, each sex endured reproductive costs associated with local warming scenario: females incurred reduced mating success, and males bore decreased fertility (lower number of eupyrene sperms within spermatophore). Our results indicate that global warming should adversely impact the reproductive success of L. botrana and the local abundance of this pest. In terms of pest management, our findings might contribute to the increase in the ecological realism of PBDMs and improve the reliability of their predictions about the population dynamics of L. botrana.

Tracking Short-Range Attraction and Oviposition of European Grapevine Moths Affected by Volatile Organic Compounds in a Four-Chamber Olfactometer

The identification of volatile organic compounds (VOCs) leading to short-range attraction and oviposition of the European grapevine moth Lobesia botrana and European grape berry moth Eupoecilia ambiguella (Lepidoptera: Tortricidae) is crucial in order to establish bait-based decision support systems for control of these pests. Therefore, we developed a method to measure the real-time behavioral response of female moths to VOCs using a four-chamber olfactometer coupled with a video tracking system. Ten synthetic VOCs were selected for this study: (S)-(−)-perillaldehyde, (E)/(Z)-linalool oxide, (±)-limonene, linalool, (E)-β-caryophyllene, α/β-farnesene, (−)-α-cedrene, methyl salicylate and cumene. The effect of VOCs on egg deposition was determined using a dual-choice oviposition test, whereas perception by female antennae was verified using electroantennography (EAG). During video tracking, females responded to volatile compounds emitted by grapevine with higher antennae and ovipositor activity than to air control. (E)/(Z)-linalool oxide, cumene and (S)-(−)-perillaldehyde released ovipositor activity of L. botrana, while the latter provoked oviposition. (R)/(S)-limonene affected ovipositor activity of E. ambiguella, whereas none of the VOCs tested attracted for oviposition. The results suggest that females have the ability to perceive specific VOCs by the antennae but also by the ovipositor, which could attract or repel for egg deposition.

EAG Responses of Adult Lobesia botrana Males and Females Collected from Vitis vinifera and Daphne Gnidium to Larval Host-Plant Volatiles and Sex Pheromone.

We analysed electroantennogram (EAG) responses of male and female adults of the European grapevine moth Lobesia botrana (Denis et Schiffermüller) (Lepidoptera: Tortricidae) collected as larvae from grapevine (Vitis vinifera L.) and flax-leaved daphne (Daphne gnidium L.). The host-plant odorants tested were either V. vinifera-specific [1-octen-3-ol, (E)-β-farnesene, (E)-4,8-dimethyl-1,3,7-nonatriene], D. gnidium-specific (2-ethyl-hexan-1-ol, benzothiazole, linalool-oxide, ethyl benzanoate), or were shared by both host-plants (linalool, methyl salicylate). Sex pheromone compounds were also tested. The male response to the major pheromone component (E7,Z9-12:Ac) was higher than to any other stimuli, whereas the response to the minor pheromone components (E7,Z9-12:OH and Z9-12:Ac) was not different from the response to the plant odorants. The female response to pheromone was lower or not different from that to plant odorants. Methyl salicylate elicited a higher response in females and (E)-β-farnesene elicited a higher response than several other plant odorants in both sexes. Non-significant interactions between host-plant odorant and sex indicated an absence of sex specialization for host-plant volatile detection. The lack of a significant interaction between plant volatiles and larval host-plants suggested that there was no specialization for plant-volatile detection between V. vinifera and D. gnidium individuals.

Characterization of entomopathogenic fungi from vineyards in Argentina with potential as biological control agents against the European grapevine moth Lobesia botrana

Biological control by entomopathogenic fungi is a possible alternative to chemical insecticides. As the grapevine moth Lobesia botrana (Lepidoptera: Tortricidae), recently introduced in Argentina, is now the major pest in most of the vineyards in the country despite quarantine regulations, native entomopathogenic fungi could be a preferable alternative to current synthetic insecticides. Thus, the aim of this study was to characterize native fungus strains isolated from 45 soil samples, using larvae of L. botrana as bait insect, and infected arthropods from the wine-growing region in the west of Argentina. Sixteen strains were identified, belonging to two species: four strains to Beauveria bassiana (Hypocreales: Cordycipitaceae) and 12 strains to Metarhizium robertsii (Hypocreales: Clavicipitaceae). Based on their physiological features, M. robertsii strains collected from the west region of Argentina seem to be the most tolerant to the high temperatures specific to this region. Therefore, being well adapted to Argentinean climate conditions, some of the native M. robertsii could be proposed as biological control agents against L. botrana.

Prey selection behaviour in the multicoloured Asian ladybird, Harmonia axyridis (Coleoptera: Coccinellidae)

The multicoloured Asian ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is a generalist predator of aphids and other soft-bodied insects. Its diet leads to negative impacts on non-target species, despite its beneficial effects offered as biocontrol agent. Herein, we evaluated prey preferences and predation success of H. axyridis adults and 4th instar larvae exposed to binary prey combinations of insects commonly found in Italian vineyards. These binary combinations included a classic prey, Aphis craccivora (Hemiptera: Aphididae) and an alternative prey, i.e., first instar larvae of the European grapevine moth Lobesia botrana (Lepidoptera: Tortricidae), second instar larvae of H. axyridis, to evaluate cannibalistic behaviour of H. axyridis, fourth instar larvae of the non-target ladybird Scymnus apetzi (Coleoptera: Coccinellidae), to evaluate intra-guild predation. Results showed that H. axyridis larvae and adults can act as potential predators of the moth pest L. botrana. They were also able to predate the non-target coccinellid species S. apetzi, thus adversely affecting aphidophagous guilds. Harmonia axyridis larvae did not significantly prefer to predate A. craccivora over the other tested preys. Harmonia axyridis adults did not show significant preferences on A. craccivora over S. apetzi larvae, whereas they prefer A. craccivora over L. botrana and H. axyridis larvae. As a general trend, the prey selection time was shorter in H. axyridis larvae, if compared to adults. Overall, our study adds basic knowledge to the prey location behaviour of H. axyridis larvae and adults, showing main differences in predation parameters of larvae and adults of this species evaluating selected binary combinations of potential preys.

Elevated atmospheric CO2 concentrations alter grapevine (Vitis vinifera) systemic transcriptional response to European grapevine moth (Lobesia botrana) herbivory

Atmospheric carbon dioxide (CO2) concentrations are among the chief factors shaping the mode and magnitude of interactions between plants and herbivorous insects. Here, we describe the first global analysis of systemic transcriptomic responses of grapevine Vitis vinifera plants to feeding of European grapevine moth Lobesia botrana larvae at future elevated CO2 concentrations. The study was conducted on mature, fruit-bearing grapevine plants under ambient and elevated CO2 concentrations in a grapevine free-air carbon dioxide enrichment (FACE) facility. Grapevine transcriptional response to herbivory was clearly dependent on phenological stage, with a higher number of differentially expressed genes identified at fruit development compared to berry ripening. At fruit development, more transcripts were differentially expressed as a response to herbivory under elevated compared to ambient CO2 concentrations. Classification of the respective transcripts revealed that in particular genes involved in metabolic pathways, biosynthesis of secondary metabolites and plant-pathogen interactions were significantly enriched. Most of these genes had similar expression patterns under both CO2 concentrations, with a higher fold-change under elevated CO2 concentrations. Differences in expression levels of a subset of herbivory responsive genes were further validated by RT-qPCR. Our study indicates that future elevated CO2 concentrations will affect interactions between grapevine plants and one of its key insect pests, with consequences for future relevance of L. botrana in worldwide viticulture.

Physical factors influencing the oviposition behaviour of European grapevine moths Lobesia botrana and Eupoecilia ambiguella

AbstractUncovering the entire process of oviposition could enable the development of innovative pest control strategies. The European grapevine moth Lobesia botrana as well as the European grape berry moth Eupoecilia ambiguella are serious insect pests, which still threaten viticulture in many parts of the world. By creating an artificial semiochemical emitting surface, in form of a card, we tried to develop an egg‐monitoring tool for the oviposition of these two species in vineyards. The idea was to create a decision support system that facilitates timing and necessity of insecticide treatments. This article deals exclusively with the initial step towards the development of this tool: the influence of physical factors (colour, shape or texture) of a surface on the oviposition behaviour of L. botrana and E. ambiguella under laboratory conditions. The acceptance of different artificial substrates as oviposition site was analysed exclusive of volatile organic compounds emitted by a host plant. We investigated particular colours of the surface, which could be a visual stimulus to trigger the oviposition of both species. Apparently, the colour green, the texture of the material and the light conditions turned out to be highly important stimuli for oviposition.

Adjusting the scent ratio: using genetically modified Vitis vinifera plants to manipulate European grapevine moth behaviour.

SummaryHerbivorous insects use olfactory cues to locate their host plant within a complex olfactory landscape. One such example is the European grapevine moth Lobesia botrana, a key pest of the grape in the Palearctic region, which recently expanded both its geographical and host plant range. Previous studies have showed that a synthetic blend of the three terpenoids, (E)‐β‐caryophyllene, (E)‐β‐farnesene and (E)‐4,8‐dimethyl‐1,3,7‐nonatriene (DMNT), was as attractive for the moth as the complete grape odour profile in laboratory conditions. The same studies also showed that the specific ratio of these compounds in the grape bouquet was crucial because a percentage variation in any of the three volatiles resulted in almost complete inhibition of the blend's attractiveness. Here, we report on the creation of stable grapevine transgenic lines, with modified (E)‐β‐caryophyllene and (E)‐β‐farnesene emission and thus with an altered ratio compared to the original plants. When headspace collections from these plants were tested in wind tunnel behavioural assays, they were less attractive than control extracts. This result was confirmed by testing synthetic blends imitating the ratio found on natural and transformed plants, as well as by testing the plants themselves. With this evidence, we suggest that a strategy based on volatile ratio modification may also interfere with the host‐finding behaviour of L. botrana in the field, creating avenues for new pest control methods.