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This project has received funding from the European Union's Seventh Framework Programme for research, technological development and demonstration under grant agreement no 613678

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Strategies to develop effective, innovative and practical approaches to protect major european fruit crops from pests and pathogens

Publications

New insights on the bacterial canker of kiwifruit (Pseudomonas syringae pv. actinidiae)

Article Type: Review Article

Authors: Donati , I | Buriani , G | Cellini , A | Mauri , S | Costa , G | Spinelli , F

Affiliations: Department of Agricultural Sciences, Alma Mater Studiorum – University of Bologna, Viale Fanin, Bologna, Italy

Abstract: Since 2008, Pseudomonas syringae pv. actinidiae, the causal agent of bacterial canker of kiwifruit has become the main pathogen of yellow and green fleshed kiwifruit. All major kiwifruit producing countries in the world have been affected by this bacterial pathogen, leading to substantial economic losses. This review presents the current knowledge on various aspects about the origin, epidemiology, detection and control strategies of Pseudomonas syringae pv. actinidiae.

Keywords: Bacterial diseases; fruit trees; disease diagnosis; control strategies; physiological and molecular plant-pathogen interaction

DOI: 10.3233/JBR-140073

Journal of Berry Research, 4(2), pp.53-67.
Published 24 July 2014

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Efficacy of Commercially Available Invertebrate Predators against Drosophila suzukii

Article Type: Article

Authors: Cuthbertson , A. G. S | Blackburn , L. F | Audsley , N.

Abstract: Drosophila suzukii has been recorded in the UK since the end of 2012. To date, reports of serious damage have been rare. Previous research has demonstrated that there are chemicals available within the UK that are efficient in dealing with D. suzukii. However, few effective chemicals for use by the organic sector have been identified; equally the addition of “new” insecticides into previously stable ecosystems can have negative impacts upon natural enemies and so disrupt control strategies that have developed over a period of time. Therefore, there is a need also to screen for potential biological control agents for D. suzukii. The following commercially available predatory species were evaluated for their potential to act as control agents for D. suzukii: Orius majusculus, Orius laevigatus, Atheta coriaria, Hypoaspis miles and Anthocoris nemoralis. This set of natural enemies could potentially target several life stages of D. suzukii (larvae, pupae and adults). All species, except H. miles, fed on D. suzukii life stages to some extent. Hypoaspis miles displayed no impact upon D. suzukii populations. Anthocoris nemoralis displayed a tendency to feed upon more male than female adult D. suzukii and caused 45% mortality after five days. None of the natural enemies trialed were able to control D. suzukii individually. However, these and other non-commercially produced species will all play a role within a given ecosystem in controlling D. suzukii populations.

Keywords: Drosophila suzukii; natural enemies; predation

DOI: 10.3390/insects5040952

Insects, 5(4), pp.952-960.
Published 28 Nov 2014

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Insights into function and evolution of parasitoid wasp venoms

Article Type: Review

Authors: Poirié, M | Colinet, D | Gatti , J-L.

Abstract: Most species in the order Hymenoptera are parasitoids that lay eggs and develop in or on the body of arthropod hosts. Several factors contribute to successful parasitism including venoms that wasps inject into hosts when ovipositing. Here, we review the composition, function and diversity of parasitoid venoms with emphasis on studies of wasps that parasitize hosts in the genus Drosophila. The comparative literature indicates that some closely related species parasitizing the same host do not share any abundant venom protein while unrelated species sometimes have the same major venom component. Within species, studies also identify intraspecific variation that suggests parasitoid venoms may rapidly evolve. Overall, however, our picture of venom function remains largely unclear and will require additional comparative data on the composition of venoms from a greater diversity of species than exists currently. Further advances will come mainly from experimental data using functional tools, such as RNA interference.

DOI: 10.1016/j.cois.2014.10.004

Journal of Mass Spectrometry, 50(5), pp.756-765, 2014
Published online 25 Oct 2015

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Genomic and peptidomic analyses of the neuropeptides from the emerging pest, Drosophila suzukii

Article Type: Article

Authors: Audsley, N | Down, R. E. | Isaac, E. R.

Abstract: Drosophila suzukii is a highly polyphagous invasive pest which has been recently introduced into Europe and North America, where it is causing severe economic losses through larval infestations of stone and berry fruits. The peptidome of the selected nervous tissues of adult D. suzukii was investigated as a first step in identifying potential targets for the development of novel insecticides. Through in silico analyses of the D. suzukii genome databases 28 neuropeptide families, comprising more than 70 predicted peptides were identified. Using a combination of liquid chromatography and mass spectrometry of tissue extracts, 33 predicted peptides, representing 15 different peptide families were identified by their molecular masses and a total of 17 peptide sequences were confirmed by ion fragmentation. A comparison between the peptides and precursors of D. suzukii and D. melanogaster shows they are highly conserved, with differences only identified in the amino acid sequences of the peptides encoded in the FMRFamide, hugin and ecydysis triggering hormone precursors. All other peptides predicted and identified from D. suzukii appear to be identical to those previously characterized from D. melanogaster. Adipokinetic hormone wasonly identified in the corpus cardiacum, other peptides present included short neuropeptide F, a pyrokininand myosuppressin, the latter of which was the only peptide identified from the crop nerve bundle. Peptides present in extracts of the brain and/or thoracico-abdominal ganglion included allatostatins,cardioacceleratory peptide 2b, corazonin, extended FMRFamides, pyrokinins, myoinihibitory peptides,neuropeptide-like precursor 1, SIFamide, short neuropeptide F, kinin, sulfakinins and tachykinin related peptides.

Keywords: Spotted winged Drosophila; invasive pest; neuropeptide; MALDI-TOF mass spectrometry; neurohormone

DOI: 10.1016/j.peptides.2014.08.006

Peptides, 68, pp.33-42, 2014
Published online 23 August 2014

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Preliminary Screening of Potential Control Products against Drosophila suzukii

Article Type: Article

Authors: Cuthbertson, A. G. | Collins, D. A. | Blackburn, L. F. | Audsley, N. | Bell, H. A.

Abstract: The first recording of Drosophila suzukii in the UK occurred in the south of England during August 2012. Since then sticky traps have continued to record the presence of individuals. Several products (both chemical and biological) were investigated for their efficacy against different life-stages of the pest. Both direct and indirect exposure to control products was assessed. Spinosad, chlorantraniliprole and the experimental product, TA2674, showed excellent potential as control agents when used as either a pre- or post-dipping treatment for blueberries with mortalities of 100%, 93% and 98% mortality, respectively, being achieved following pre-treatment. Direct spray application of all products tested had limited impact upon adult flies. Highest mortality (68%) was achieved following direct application of TA2674. Entomopathogenic agents (nematodes and fungi) tested appeared to reduce fly population development (ranges of 34–44% mortality obtained) but would seem unable to eradicate outbreaks. The potential of the tested products to control D. suzukii is discussed.

Keywords: Drosophila suzukii; control; pesticide

DOI:10.3390/insects5020488

Insects, 5(2), pp.488-498, 2014
Published 20 June 2014

Link

G Protein coupled receptors as targets for next generation pesticides


Article Type: Review

Authors: Audsley, N. | Down, R. E.

Abstract: There is an on-going need for the discovery and development of new pesticides due to the loss of existing products through the continuing development of resistance, the desire for products with more favourable environmental and toxicological profiles and the need to implement the principles of integrated pest management.

Insect G protein coupled receptors (GPCRs) have important roles in modulating biology, physiology and behaviour, including reproduction, osmoregulation, growth and development. Modifying normal receptor function by blocking or over stimulating its actions may either result in the death of a pest or disrupt its normal fitness or reproductive capacity to reduce pest populations. Hence GPCRs offer potential targets for the development of next generation pesticides providing opportunities to discover new chemistries for invertebrate pest control. Such receptors are important targets for pharmaceutical drugs, but are under-exploited by the agro-chemical industry. The octopamine receptor agonists are the only pesticides with a recognized mode of action, as described in the classification scheme developed by the Insecticide Resistance Action Committee, that act via a GPCR.

The availability of sequenced insect genomes has facilitated the characterization of insect GPCRs, but the development and utilization of screening assays to identify lead compounds has been slow. Various studies using knock-down technologies or applying the native ligands and/or neuropeptide analogues to pest insects in vivo, have however demonstrated that modifying normal receptor function can have an insecticidal effect.

This review presents examples of potential insect neuropeptide receptors that are potential targets for lead compound development, using case studies from three representative pest species, Tribolium castaneum, Acyrthosiphon pisum, and Drosophila suzukii.

Functional analysis studies on T. castaneum suggest that GPCRs involved in growth and development (eclosion hormone, ecdysis triggering hormone and crustacean cardioacceleratory peptide receptors) as well as the dopamine-2 like, latrophilin-like, starry night, frizzled-like, methuselah-like and the smoothened receptors may be suitable pesticide targets.

From in vivo studies using native ligands and peptide analogues, receptors which appear to have a role in the regulation of feeding in the pea aphid, such as the PISCF-allatostatin and the various “kinin” receptors, are also potential targets.

In Drosophila melanogaster various neuropeptides and their signalling pathways have been studied extensively. This may provide insights into potential pesticide targets that could be exploited in D. suzukii. Examples include the sex peptide receptor, which is involved in reproduction and host seeking behaviours, and those responsible for osmoregulation such as the diuretic hormone receptors.

However the neuropeptides and their receptors in insects are often poorly characterized, especially in pest species. Although data from closely related species may be transferable (e.g. D. melanogaster to D. suzukii), peptides and receptors may have different roles in different insects, and hence a target in one insect may not be appropriate in another. Hence fundamental knowledge of the roles and functions of receptors is vital for development to proceed.

Keywords: GPCR; neuropeptide; insect; insecticide; Drosophila suzukii; Tribolium castaneum; Acyrthosiphon pisum

DOI : 10.1016/j.ibmb.2015.07.014

Insect biochemistry and molecular biology, 67, pp.27-37, 2015
Published online 29 July 2015

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Identification of pests and pathogens recorded in Europe with relation to fruit imports

Article Type: EPPO Bulletin

Authors: Steffen, K | Grousset, F. | Schrader, G. | Petter, F. | Suffert, M.

Abstract: Within the framework of the EU project DROPSA (‘Strategies to develop effective, innovative and practical approaches to protect major European fruit crops from pests and pathogens’), a review on pests (including pathogens) that have fruit species as their host plants was conducted. The focus was on pests that have been introduced into Europe or were found in the fruit trade during the last 10–15 years. Among the 387 recorded pests, the following groups were identified: 1. fruit and vinegar flies, 2. scale insects, 3. fungi, 4. plant viruses, 5. bacteria, 6. pests of unknown risk, 7. tropical fruit pests, 8. pests that had an unexpected change of hosts, 9. fruit pests not likely to be transported on fruit and 10. ‘hitchhikers’ (non-fruit pests intercepted on fruit/fruit plants, fruit pests intercepted on other commodities than fruit). The large number of pests identified, from different taxonomic groups and origins, shows that fruit are an important pathway for pests, threatening fruit production in Europe.

DOI: 10.1111/epp.12215

EPPO Bull, 45(2): 223–239, 2015
Published 26 June 2015

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EU-project DROPSA: first achievements regarding pathway analyses for fruit pests [free access]

Article Type: EPPO Bulletin

Authors: Steffen, K | Grousset, F. | Schrader, G. | Petter, F. | Suffert, M.

Abstract: The EU project ‘DROPSA’ started in 2014 and aims to improve plant health strategies in the fruit sector. The project is being conducted by an international consortium of 26 partners consisting of phytosanitary organizations, companies, research institutes and universities and will last 50 months. Results will be disseminated via conventional publications and will be brought together in the development of risk-based strategies to prevent the introduction of new fruit pests. This article describes the task related to the preparation of alert lists of pests that may be introduced into Europe with the trade of fruit. Activities of this task include the investigation of pathways of introduction for fruit pests into Europe, the development of alert lists for selected fruit crops and a review of current legislation. A review of introductions, interceptions and outbreaks that occurred during the last 10–15 years was conducted and is summarized, showing the relevance of fruit trade for the international movement of pests. Work has started on the development of alert lists for selected pathways. In this context, important fruit crops (including Malus, Vaccinium, Vitis, Citrus) were selected.

DOI: 10.1111/epp.12179

EPPO Bull, 45(1): 148–152, 2015
Published 7 April 2015

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Further Screening of Entomopathogenic Fungi and Nematodes as Control Agents for Drosophila suzukii

Article Type: Article

Authors: Cuthbertson, A. G. | Audsley, N.

Abstract: T Drosophila suzukii populations remain low in the UK. To date, there have been no reports of widespread damage. Previous research demonstrated that various species of entomopathogenic fungi and nematodes could potentially suppress D. suzukii population development under laboratory trials. However, none of the given species was concluded to be specifically efficient in suppressing D. suzukii. Therefore, there is a need to screen further species to determine their efficacy. The following entomopathogenic agents were evaluated for their potential to act as control agents for D. suzukii: Metarhizium anisopliae; Isaria fumosorosea; a non-commercial coded fungal product (Coded B); Steinernema feltiae, S. carpocapsae, S. kraussei and Heterorhabditis bacteriophora. The fungi were screened for efficacy against the fly on fruit while the nematodes were evaluated for the potential to be applied as soil drenches targeting larvae and pupal life-stages. All three fungi species screened reduced D. suzukii populations developing from infested berries. Isaria fumosorosea significantly (p < 0.001) reduced population development of D. suzukii from infested berries. All nematodes significantly reduced adult emergence from pupal cases compared to the water control. Larvae proved more susceptible to nematode infection. Heterorhabditis bacteriophora proved the best from the four nematodes investigated; readily emerging from punctured larvae and causing 95% mortality. The potential of the entomopathogens to suppress D. suzukii populations is discussed.

Keywords: Drosophila suzuki;, biocontrol; entomopathogenic nematodes; fungi; integrated pest management

DOI: 10.3390/insects7020024

Insects, 7(2), p.24, 2016
Published 9 June 2016

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Pseudomonas syringae pv. actinidiae strains isolated from past and current epidemics to Actinidia spp. reveal a diverse population structure of the pathogen

P. Ferrante :M. Scortichini Consiglio per la ricerca in agricoltura e l’analisi dell’economia
agraria (C.R.A.), Centro di Ricerca per la Frutticoltura, Via di Fioranello, 52, I-00134 Rome, Italy
e-mail: marco.scortichini@entecra.it

Article Type: Article

Authors: Ferrante, P. | Takikawa, Y. | Scortichini, M.

Abstract: A total of 40 Pseudomonas syringae pv. actinidiae (Psa) strains isolated from past and current epidemics of kiwifruit bacterial canker worldwide were compared using repetitive-sequence PCR (rep-PCR) fingerprinting with BOX, ERIC and REP primer sets. The strains were also assessed for the presence of 23 type III secretion system effector genes, tolerance to sodium arsenite, the presence of coronatine and phaseolotoxin and for growth trends in Actinidia deliciosa leaves. Rep-PCR revealed the occurrence of 11 different Psa lineages among the strains and indicated a relevant genetic variability within the strains isolated in Japan during 1984–2011, whereas all strains obtained from the current pandemic showed the same banding pattern. All lineages showed the same growth trend when inoculated into A. deliciosa leaves. The difference between Psa strains from past and current epidemics was confirmed by the detection of different repertoires of type III effector protein genes. Not all Psa strains isolated in Japan during past epidemics of kiwifruit bacterial canker amplify genes of the argK-tox cluster of phaseolotoxin, suggesting their absence or gene mutation. The results of an arsenic tolerance assay indicated that almost all strains isolated in Italy during the current epidemic of kiwifruit bacterial canker were relatively tolerant to 0.15–0.35 mM sodium arsenite, whereas those isolated in Chile and New Zealand were very sensitive. Remarkably, the two strains from China were tolerant or very sensitive. Collectively, these data indicate a composite population structure of this pathogen, which was able to diversify in Japan during 27 years of recurrent infections to A. deliciosa. The current naming of Psa populations based on their numbering and presence/absence of phytotoxins should be reconsidered.

Keywords: Kiwifruit bacterial canker; repetitive-sequence PCR; Type III secretion system; effectors; pandemic; phaseolotoxin

DOI: 10.1007/s10658-015-0643-6
European journal of plant pathology, 142(4), pp.677-689, 2015
Published online 26 March 2015

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Infestation of Wild and Ornamental Noncrop Fruits by Drosophila suzukii (Diptera: Drosophilidae)

Article Type: Article

Authors: Lee , J. C. | Dreves , A. J. | Cave , A. M. | Kawai , S. | Isaacs , R. | Miller , J. C. | Van Timmeren , S. | Bruck , D. J. |

Abstract: Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) is a pest of small fruits and cherries, and has also been noted to infest a variety of wild, ornamental, and uncultivated hosts. Identifying alternative hosts is critical for pest management. Research objectives were to: 1) survey fruits in the field for natural infestation of D. suzukii, 2) determine the susceptibility of fruits in laboratory no-choice studies, and 3) evaluate short-range preference between simultaneously ripe alternative hosts and cultivated fruits in laboratory choice studies. Field surveys identified new hosts or confirmed previously reported hosts including: Berberis aquifolium Pursh, Oregon grape; Cornus spp., dogwood; Cotoneaster lacteus W.W. Smith, milkflower cotoneaster; Elaeagnus umbellata Thunberg, Autumn olive; Frangula purshiana (de Candolle) A. Gray, cascara buckthorn; Lindera benzoin (L.) Blume, spicebush; Lonicera caerulea L., blue honeysuckle; Morus sp., mulberry; Phytolacca americana L., pokeweed; Prunus avium (L.) L., wild cherry; Prunus laurocerasus L., cherry laurel; Prunus lusitanica L., Portuguese laurel; Rubus armeniacus Focke, Himalaya blackberry; Rubus spectabilis Pursh, salmonberry; Sambucus nigra L., black elderberry; Sarcococca confusa Sealy, sweet box; Solanum dulcamara L., bittersweet nightshade; and Symphoricarpos albus (L.) S.F. Blake, snowberry. High fruit infestations were observed in S. confusa during April–May and Lonicera spp. in June before most commercial fruits ripen. From both field and laboratory studies, there was no evidence of susceptibility during the estimated ripe period Crataegus L. ‘Autumn Glory,’ hawthorn; Ilex crenata Thunberg, Japanese holly; Nandina domestica Thunberg, sacred bamboo; Rhaphiolepis umbellata (Thunberg) Makino, yeddo hawthorne; Rosa acicularis Lindley, prickly rose; Skimmia japonica Thunberg, Japanese skimmia; and Viburnum davidii Franchet, David’s viburnum. Lastly, laboratory choice tests identified that several fall-ripening alternative hosts were more susceptible than ‘Pinot noir’ or ‘Pinot gris’ wine grapes. By understanding host use, growers can identify high-risk areas where coordinated action may reduce infestation of D. suzukii in crops.

Keywords: Alternative host; fruit host; host range; invasive pest; spotted wing drosophila

DOI: 10.1093/aesa/sau014

Annals of the Entomological Society of America, 108 (2): 117-129, 2015
Published 5 Feb 2015

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Omics, epidemiology and integrated approach for the coexistence with bacterial canker of kiwifruit, caused by Pseudomonas syringae pv. actinidiae

Article Type: Article

Authors: Scortichini , M. | Ferrante , P. | Marcelletti , S. | Petriccione , M.

Abstract: Bacterial canker of kiwifruit, caused by Pseudomonas syringae pv. actinidiae, is a destructive disease found in all major areas of production of green-fleshed (Actinidia deliciosa) and yellow-fleshed (A. chinensis) kiwifruit of the world (i.e, Europe, China, New Zealand and Chile). A series of studies and field trials concerning epidemiology, agronomical techniques, new bactericides effectiveness as well as molecular typing analysis, genomic and proteomic, allowed us to elucidate the cycle of disease of the pathogen, to dissect its main genomic features, to point out the plant proteins involved in resistance/tolerance to the bacterium, to modify some basic agronomical techniques and to propose new compounds that currently, at least in the province of Latina and Rome, Italy, allow the farmers to coexist with the pathogen by reaching the full yield and quality of the crop as before the appearance of the disease.

Keywords: Bacterial canker of kiwifruit; chitosan; cycle of disease; genomic; proteomic

DOI: 10.4081/ija.2014.606

Italian Journal of Agronomy, 9(4), pp.163-165, 2014
Published 02 Dec 2014

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Development of Xanthomonas fragariae populations and disease progression in strawberry plants after spray-inoculation of leaves

Article Type: Article

Authors: Kastelein , P | Krijger, M | Czajkowski , R | van der Zouwen , P. S. | van der Schoor, R | Jalink , H | van der Wolf, J. M.

Abstract: Xanthomonas fragariae is the causative agent of angular leaf spot disease of strawberry. Greenhouse experiments were conducted using a X. fragariae isolate tagged with a green fluorescent protein (GFP) for detailed population dynamic studies in and on leaves after spray-inoculation. The GFP-tagged bacteria were monitored with dilution plating of leaf washings and leaf extracts, and analysis of intact leaves using a non-invasive monitoring system called PathoScreen, based on laser radiation of fluorescent cells in plant tissues and signal recording with a sensitive camera. PathoScreen was also used to monitor bacteria grown on an agar medium after leaf printing. During the first 3 days after inoculation, bacterial populations washed off leaves rapidly decreased by at least a factor of 1000, after which populations remained stable until 14 days post-inoculation (dpi), when symptoms first started to appear. Thereafter, populations increased to a level of 1012 colony-forming units (CFU) g−1 of leaf material or higher. Similarly, densities in leaf extracts were low during the first 3 days after inoculation, at a level of 100–1000 CFU g−1 of leaf tissue. Gradually populations increased to a level of 109–1012 CFU g−1 at 28 dpi. Higher densities of epiphytic populations were found on the abaxial side than on the adaxial leaf side during the first 2 weeks after inoculation. After spray-inoculation of leaves, bacterial populations released from infected plants remained low until symptoms appeared, after which plants became highly infectious, in particular under high humidity.

Keywords: Green fluorescent protein tagged bacteria; PathoScreen; population dynamics; TaqMan assay

DOI: 10.1111/ppa.12090

Plant pathology, 63(2), pp.255-263, 2014
Published 25 June 2013

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Detection and identification of Xanthomonas arboricola pv. pruni from symptomless plant material: results of an Italian test performance study

Article Type: Article

Authors: Loreti, S | Pucci, N | Perez, G | Catara, V | Scortichini, M | Bella , P | Ferrante, P | Giovanardi, D | Stefani, E.

Abstract: Xanthomonas arboricola pv. pruni, the causal agent of bacterial spot disease of stone fruits, is a regulated quarantine pathogen in the European Union, listed as an A2 pest by the European and Mediterranean Plant Protection Organization (EPPO). Because detection and identification of this pathogen is key for its management and to ensure the production of pest free propagation material, it should be based on reliable tests, in particular when dealing with symptomless material. The current EPPO diagnostic Standard (PM 7/64) does not provide specific molecular methods for detection of this pest. The present paper summarizes the results of a test-performance study (TPS) to validate, at a national level, a detection procedure for this bacterium. A working group was established in order to evaluate the performance criteria for tests included in the current EPPO Standard, and for a conventional PCR. On the basis of the obtained performance criteria, a diagnostic procedure was elaborated and then applied to perform an inter-laboratory comparison. Screening tests for the detection of the bacterium on symptomless plant material based on IF and/or PCR were proposed, in parallel with isolation on agar media. For identification two methods were suggested: a molecular test or IF. This paper reports on the results of the TPS and proposes a flow diagram for the detection and identification of X. arboricola pv. pruni.

DOI: 10.1111/epp.12194

EPPO Bulletin, 45(1), pp.41-51, 2015
Published 7 April 2015

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Redefining the global populations of Pseudomonas syringae pv. actinidiae based on pathogenic, molecular and phenotypic characteristics

Article type: Article

Authors: Ferrante , P | Scortichini , M.

Abstract: Knowing the population structure of a pathogen is fundamental for developing reliable phytosanitary legislation, detection techniques, and control strategies based on the actual aggressiveness and distribution of the pathogen. Currently, four populations of Pseudomonas syringae pv. actinidiae (Psa) have been described: Psa 1, Psa 2, Psa 3 and Psa 4. However, diagnostic assays specific for Psa populations do not detect Psa 4, the less virulent (LV) strains isolated in New Zealand. Similarly, multilocus sequence typing (MLST) of housekeeping genes, or broad Psa strain genome comparisons, revealed that Psa 4-LV strains clustered separately from other Psa populations. In order to examine whether the placement of Psa 4 in the pathovar actinidiae was appropriate, various tests were carried out. It was shown that the Psa 4-LV strains induced leaf and shoot wilting in Prunus cerasus, extensive necrotic lesions in Capsicum annuum fruits, and no significant symptoms in Actinidia deliciosa. Moreover, repetitive-sequence PCR fingerprinting, type III secretion system effector protein genes detection and colony morphology clearly indicated the distinctiveness of Psa 4-LV strains from the other three Psa populations. Rep-PCR molecular typing revealed a high similarity of the Psa 4-LV strains with members of Pseudomonas avellanae species. The Psa 4-LV strains, most probably, belong to a new, still unnamed pathovar. It was concluded that the Psa 4-LV strains isolated in New Zealand do not belong to the pathovar actinidiae, and, consequently, three Psa populations pathogenic to Actinidia spp. should currently include Psa 1, Psa 2 and Psa 3.

Keywords: Actinidia chinensis; Actinidia deliciosa; bacterial canker of kiwifruit; host range tests; pathovar

DOI: 10.1111/ppa.12236

Plant Pathology, 64(1), pp.51-62, 2015
Published 01 Feb 2015

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The Kiwifruit Emerging Pathogen Pseudomonas syringae pv. actinidiae Does Not Produce AHLs but Possesses Three LuxR Solos

Article type: Article

Authors
: Patel, H. K. | Ferrante, P. | Covaceuszach, S. | Lamba, D. | Scortichini, M | Venturi, V.

Abstract: Pseudomonas syringae pv. actinidiae (Psa) is an emerging phytopathogen causing bacterial canker disease in kiwifruit plants worldwide. Quorum sensing (QS) gene regulation plays important roles in many different bacterial plant pathogens. In this study we analyzed the presence and possible role of N-acyl homoserine lactone (AHL) quorum sensing in Psa. It was established that Psa does not produce AHLs and that a typical complete LuxI/R QS system is absent in Psa strains. Psa however possesses three putative luxR solos designated here as PsaR1, PsaR2 and PsaR3. PsaR2 belongs to the sub-family of LuxR solos present in many plant associated bacteria (PAB) that binds and responds to yet unknown plant signal molecules. PsaR1 and PsaR3 are highly similar to LuxRs which bind AHLs and are part of the canonical LuxI/R AHL QS systems. Mutation in all the three luxR solos of Psa showed reduction of in planta survival and also showed additive effect if more than one solo was inactivated in double mutants. Gene promoter analysis revealed that the three solos are not auto-regulated and investigated their possible role in several bacterial phenotypes.

DOI: 10.1371/journal.pone.0087862

PloS one, 9 (1), pp.e87862, 2014
Published 31 Jan 2014

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Current SWD IPM tactics and their practical implementation in fruit crops across different regions around the world

Article Type: Article

Authors: Haye, T | Girod, P | Cuthbertson, A. G. S. | Wang, X. G. | Daane , K. M. | Hoelmer, K. A.| Baroffio, C. |Zhang, J. P. |Desneux, N.

Affiliations: CABI, Switzerland – Fera Science Ltd., UK - Department of Environmental Science, Policy and Management, University of California, USA - USDA Agricultural Research Service, USA, - Agroscope IPS, Research Center Conthey (VS), Switzerland - MoA-CABI Joint Laboratory for Biosafety, China - INRA (French National Institute for Agricultural Research), France

Abstract: After its arrival in 2008, the Spotted Wing Drosophila (SWD), Drosophila suzukii, has emerged as a harmful invasive insect pest in North America and Europe. This highly polyphagous pest is a major threat to many economically important fruit crops and is also known to develop on a wide variety of natural host plants. In Asia, Europe and North America, different control measures are applied against SWD, such as chemical, biological, and cultural control. Current controls of SWD rely primarily on the application of insecticides, but cultural management tactics such as sanitation and the use of nets provide a good alternative in some crops. Biological control measures, such as conservation of existing natural enemies in invaded areas, introduction of specialized larval parasitoids from Asia for classical biological control and the use of indigenous parasitoids for augmentative control, are currently being investigated and may become an important management tool in the near future for an area-wide control of SWD.

Keywords: Drosophila Suzukii; Biological control; Cultural control; Chemical control

DOI: 10.1007/s10340-016-0737-8

J Pest Sci (2016) 89: 643.
Published 8 February 2016

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Development of Drosophila suzukii at low temperatures in mountain areas

Article Type: Article

Authors: Tonina, L | Mori, N | Giomi, F | Battisti, A

Affiliations: Department of Agronomy Food Natural resources Animals and Environment (DAFNAE), University of Padova, Legnaro, Italy

Abstract: As a fly tracking the availability of fruits along climatic gradients, Drosophila suzukii is deemed to be rather flexible in relation to environmental factors, among which temperature is a major player. We sampled potential wild host fruits of D. suzukii along two elevational gradients in mountain areas of north-eastern Italy, in order to measure fly performance in relation to temperature. In addition, we used a strong natural temperature gradient in an open-top cave, covering the lower range of temperatures known for D. suzukii, to deploy laboratory stock colonies to mimic conditions existing along elevational gradients. At least nine wild host species yielded adults of D. suzukii in the mountain area (Daphne mezereum, Lonicera alpigena,Lonicera caerulea, Lonicera nigra, Lonicera xylosteum, Rubus caesius, Rubus saxatilis, Sambucus nigra, and Sambucus racemosa) when the daily average temperature in the three preceding weeks was at least 11.1 °C. Similar results were obtained with the laboratory colonies reared on an artificial medium in the cave, where oviposition and development from egg to adult occurred at above 11.6 °C. Both values are lower than previously recorded lower thresholds for development at both constant and fluctuating temperatures. These findings indicate that D. suzukii performs well at low temperatures, suggesting that population buildup may occur even under these conditions, with likely consequences on crops and wild host reproduction.

Keywords: Spotted wing Drosophila; Performance; Fluctuating temperature; Host plant

DOI: 10.1007/s10340-016-0730-2

Journal of Pest Science, 3(89), pp.667-678
Published 23 January 2016

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Non-crop plants used as hosts by Drosophila suzukii

Article Type: Article

Authors: Kenis, M | Tonina, L | Eschen, R | van der Sluis, B | Sancassani, M | Mori, N| Haye, T | Helsen, H

Affiliations: CABI, Switzerland - Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Italy - Applied Plant Research, Wageningen University & Research, The Netherlands

Abstract: The invasive spotted wing drosophila Drosophila suzukii, a fruit fly of Asian origin, is a major pest of a wide variety of berry and stone fruits in Europe. One of the characteristics of this fly is its wide host range. A better knowledge of its host range outside cultivated areas is essential to develop sustainable integrated pest management strategies. Field surveys were carried out during two years in Italy, the Netherlands and Switzerland. Fruits of 165 potential host plant species were collected, including mostly wild and ornamental plants. Over 24,000 D. suzukii adults emerged from 84 plant species belonging to 19 families, 38 of which being non-native. Forty-two plants were reported for the first time as hosts of D. suzukii. The highest infestations were found in fruits of the genera Cornus, Prunus, Rubus, Sambucus and Vaccinium as well as in Ficus carica, Frangula alnus, Phytolacca americana and Taxus baccata. Based on these data, management methods are suggested. Ornamental and hedge plants in the vicinity of fruit crops and orchards can be selected according to their susceptibility to D. suzukii. However, the widespread availability and abundance of non-crop hosts and the lack of efficient native parasitoids suggest the need for an area-wide control approach.

Keywords: Spotted wing Drosophila; Fruit fly; Host range; Invasive species

DOI: 10.1007/s10340-016-0755-6

Journal of pest science, 89(3), pp.735-748
Published 24 March 2016

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Statistical analysis of the individual variability of 1D protein profiles as a tool in ecology: an application to parasitoid venom

Article Type: Article

Authors: Mathé‐Hubert, H. | Gatti, J.L. | Colinet, D. | Poirie, M. | Malausa, T

Abstract: Understanding the forces that shape eco-evolutionary patterns often requires linking phenotypes to genotypes, allowing characterization of these patterns at the molecular level. DNA-based markers are less informative in this aim compared to markers associated with gene expression and, more specifically, with protein quantities. The characterization of eco-evolutionary patterns also usually requires the analysis of large sample sizes to accurately estimate interindividual variability. However, the methods used to characterize and compare protein samples are generally expensive and time-consuming, which constrains the size of the produced data sets to few individuals. We present here a method that estimates the interindividual variability of protein quantities based on a global, semi-automatic analysis of 1D electrophoretic profiles, opening the way to rapid analysis and comparison of hundreds of individuals. The main original features of the method are the in silico normalization of sample protein quantities using pictures of electrophoresis gels at different staining levels, as well as a new method of analysis of electrophoretic profiles based on a median profile. We demonstrate that this method can accurately discriminate between species and between geographically distant or close populations, based on interindividual variation in venom protein profiles from three endoparasitoid wasps of two different genera (Psyttalia concolor, Psyttalia lounsburyi and Leptopilina boulardi). Finally, we discuss the experimental designs that would benefit from the use of this method.

DOI: 10.1111/1755-0998.12389

Molecular ecology resources, 15(5), pp.1120-1132.
Published 11 March 2015

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Field efficacy of a zinc-copper-hydracid of citric acid biocomplex compound to reduce oozing from winter cankers caused by pseudomonas syringae pv. actinidiae to actinidia spp.

Article Type: Article

Authors: Scortichini, M.

Abstract: Pseudomonas syringae pv. actinidiae (Psa) is the causal agent of bacterial canker of green-fleshed (Actinidia deliciosa) and yellow-fleshed (A. chinensis) kiwifruit and is causing severe economic losses worldwide. In Italy, a combined strategy that takes into consideration timely spray treatments to the plant canopy, a correct pruning management including the disinfection of the tools and the protection of the pruning cuts, the avoidance of excessive nitrogen fertilization and water stress, and training systems favoring a better air circulation, are giving satisfactory results in controlling the pathogen severity in the field. However, despite these efforts, the dormant phase of the plant still represents a main problem, especially in the areas where winter frosts regularly occur. During winter 2013-14 and 2014-15 in four sites, spanning from Northern to Southern Italy, the field efficacy of a zinc (4.7%)-copper (2.6%)-hydracid of citric acid (21.4%) biocomplex compound has been tested on Actinidia deliciosa and A. chinensis orchards. The biocomplex compound was applied three times, at a dose of 1.0%, to reduce the occurrence of bacterial exudates oozing out from the main trunk and leaders in early spring. During the trial, winter frosts were recorded in all sites. The biocomplex compound was more effective than a 1% Bordeaux mixture used under the same conditions. This biocomplex formulation could be used to effectively reduce the amount of exudates caused by Psa in areas where winter frost occurs regularly.

Keywords: kiwifruit bacterial canker, control, copper, zinc, cycle of disease, winter frost

DOI: 10.4454/JPP.V98I3.044

Journal: Plant Pathology, Vol 98, No 3 (2016)

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