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International audience; The French apricot production is located in the southeastern part of the country with a focused zone in the Rhone valley and close to the Mediterranean Sea. The north of Rhone valley is characterized by a continental climate while the southern region (Rhone valley and Mediterranean area) is characterized by a typical Mediterranean climate. Due to economic and adaptation constraints the apricot fruit production depends on the development of a specific range of cultivars in the different areas of cultivation. In order to enlarge the panel of, a breeding program is developed at a national level in France with the participation of CEP INNOVATION, CENTREX and INRA. The main goals of the breeding program are: the elaboration of cultivars suitable for a durable production (including resistance to pests and diseases), production regularity (including self-fertility and quality of the flowers), and fruit quality (including taste, attractiveness, and suitability for the transport). Out of a first evaluation stage in nursery, based on a MAS approach targeted onto sharka susceptibility and Self-fertility, the agronomical evaluation is performed in orchard and followed by an evaluation of the pre-selections after grafting in the 3 main areas of cultivation for integrating the adaptability. Then the ‘elite’ agronomic and commercial assessments are conducted in small orchards. The main results issued from this program are here presented with 10 blushy and purple-red cultivars including five PPV resistant ‘Aramis®’ cultivars.

International audience; ILLIAD is a French national project in which food-chain sustainability is being evaluated on four products ( wheat, rice, peach and apricot). For apricot, two difficulties for French production have been identified: i) the high cost of manpower in this culture and ii) fruit processors' dependence on surplus fruits from fresh consumption. This leads to very high variability in supply, price and quality from year to year. In this context, one solution might be dedicated orchards for processing industries. At first, cultivars well adapted to processing and with a low demand for inputs were screened for their behavior in mechanical harvest. Mechanical harvest was carried out using tree shaking ( at 40 cm from the ground) and collection on a fabric screen. Results obtained over 2 years on more than 15 cultivars and in two production areas are presented. The low mechanical damage observed just after harvesting or after 7 days of storage for a few cultivars and the possibility of optimizing shaking parameters according to agronomic and physiologic criteria ( fruit falling, maturity heterogeneity, etc.) confirm the suitability of mechanical harvesting and the opportunity to create dedicated orchards.

In autumn 2001, severe yellowing symptoms were observed on greenhouse-grown cucumbers near Perpignan (southern France). Leaf samples were collected from two sites where plants displayed symptoms ranging from limited yellowing of the older leaves to severe, complete yellowing of the whole plant. Cucurbit aphid-borne yellows virus, a polerovirus that causes similar symptoms was not detected in doubleantibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) using a specific antiserum. Total RNA was extracted from fresh leaf tissues and used in reverse transcription-polymerase chain reaction (1) with primers specific for two whitefly-borne viruses also inducing yellows and occurring in the Mediterranean basin (1): Beet pseudo yellows virus (BPYV, genus Closterovirus) transmitted by Trialeurodes vaporariorum (West.) and Cucurbit yellow stunting disorder virus (CYSDV, genus Crinivirus) transmitted by Bemisia tabaci (Genn.). No BPYV was detected in this survey, but CYSDV was present in all samples. In subsequent surveys conducted in the spring and summer of 2002, BPYV and CYSDV were detected, sometimes in mixed infections, in samples collected from the same region. The complete CYSDV coat protein gene was amplified by PCR using specific primers (2), yielding the expected-size fragment of 756 bp. The French isolate (GenBank Accession No. AY204220) shared 99.6 to 100% nucleotide sequence identity in the sequenced CP fragments (700 nt) with isolates of the most common, highly homogenous subgroup of CYSDV that has emerged recently in the Middle East, southwestern Europe (Spain and Portugal), United States, and Morocco (2). To our knowledge, this is the first report of CYSDV in France and it shows the threat represented by the current emergence of B. tabaci-transmitted viruses. References: (1) I. C. Livieratos et al. Plant Pathol. 47:362, 1998. (2) L. Rubio et al. J. Gen. Virol. 82:929, 2001.

Ce numéro est constitué d’articles de synthèse des projets DEPHY EXPE publiés à l’occasion du Colloque National DEPHY EXPE, qui s’est déroulé le 28 mai 2019 à l'Assemblée Permanente des Chambres d'Agriculture (Paris; National audience; CAP ReD aims to design and evaluate cherry, apricot, Ente plum, Japanese-American plum and mirabelle plum orchards, so that the use of phytosanitary products is halved, while maintaining the technico-economic performance. System experiments, conducted by 9 partners at 10 sites from 2013 to 2018, combined many levers of action (genetics, physics, biotechnology, biology ...), and choices were made from planting the trees to the annual management of orchards. For example, 17 low-pesticide-input control systems (LPIC) were compared each year to 11 reference systems (IFP). These LPIC systems, excluding biocontrol, achieved an average reduction of 58% of IFT (5.1 / 12.2 in IFP). The goal of “zero herbicide cultivation” was achieved in the majority of systems, of which two levers proved their worth: mechanical weeding and the woven weed control ground cover. Marketable yield was lower with the LPIC systems (-19%) except in high density orchards. CAP ReD's LPIC systems also required more work time to produce one tonne of fruit. This loss of production and efficiency is not offset by an increase in the sales price in the LPIC systems, so the economic performance is lower. Thus, the costs of production with LPIC systems is on average 20% higher, i.e. + 0.15 € / kg. 47% of LPIC systems (8/17) are classified as Economical and Efficient Systems. These are either i) high-density systems with insect nets, rain covers, dose reduction with innovative spraying techniques, but with high depreciation costs; or ii) systems of which the fruit are intended for the processing industry with lower production costs (no waste, mechanical harvesting), using decision-support tools, biocontrols and reduction of certain treatments. These results show the technical feasibility of a considerable reduction of phytosanitary product use, decreasing the risks of impacts on the environment and human health, but also the economic difficulty that these changes of practice generate for the grower, without revaluating prices.; CAP ReD vise à concevoir et évaluer des vergers de cerisier, abricotier, prunier d’Ente, prunier américano-japonais et mirabellier, permettant de réduire l’usage des produits phytosanitaires par deux, tout en conservant les performances technico-économiques. Les expérimentations systèmes, conduites par 9 partenaires dans 10 sites de 2013 à 2018, combinent de nombreux leviers d’action (génétique, physique, biotechnique, biologique…), depuis le choix à la plantation, jusqu’à la gestion annuelle des vergers. Ainsi, 17 systèmes économes en produits phytosanitaires (ECO) sont comparés chaque année à 11 systèmes de référence (PFI). Ces systèmes ECO ont permis une réduction moyenne de 58% des IFT hors biocontrôle (5.1 vs 12.2 en PFI). L’objectif « zéro herbicide » a été atteint dans la majorité des systèmes, deux leviers ont fait leur preuve : le désherbage mécanique et la bâche tissée au sol. Le rendement commercialisable est plus faible dans ECO (-19 %), sauf dans les systèmes à haute densité ou biaxe d’arbres. Les systèmes ECO de CAP ReD nécessitent aussi plus de temps de travail pour produire une tonne de fruits. Cette perte de production et d’efficience n’est pas compensée par une augmentation du prix de vente des fruits dans les systèmes ECO, aussi les performances économiques sont moindres. Ainsi, le coût de production des systèmes ECO est en moyenne supérieur de 20%, soit +0.15€/kg. 47% des systèmes ECO (n=8) sont classés Systèmes Economes et Performants (SCEP). Ce sont soit, i) des systèmes avec filets anti-insectes, bâche anti-pluie, réduction de dose avec pulvérisation innovante, conduits en haute densité ou biaxe, mais ayant de fortes charges d’amortissement ; soit ii) des systèmes valorisant leurs fruits en industrie, avec des coûts de production moindres (moins de déchet, récolte mécanique), utilisant des Outils d’Aide à la Décision, biocontrôles et impasses. Ces résultats montrent la faisabilité technique d’une forte réduction des produits phytosanitaires, diminuant les risques d’impacts sur l’environnement et la santé humaine, mais aussi la difficulté économique qu’engendrent ces changements de pratiques pour le producteur, sans revalorisation des prix.

Ce numéro est constitué d’articles de synthèse des projets DEPHY EXPE publiés à l’occasion du Colloque National DEPHY EXPE, qui s’est déroulé le 28 mai 2019 à l'Assemblée Permanente des Chambres d'Agriculture (Paris); International audience; EcoPêche aims to design and evaluate peach-nectarine orchards with a trade-off between a strong reduction of pesticides and the technico-economic performances. System experiments, conducted by 8 partners in 7 sites, combine many levers of action ranging from structural planting choices to the association of different alternative methods in the annual orchard management over the 2013-2018 period. Data analysis concern 29 systems x years Reference (REF), 36 ECO (Low pesticide use systems) and 12 organic farming (BIO) systems. Pesticide reductions excluding biocontrol products reached 52% in ECO and -77% in BIO compared with REF (21.1 IFT). Marketable yield is lower in ECO (-20%) and BIO (-64%) compared with REF (30.5 t/ha). The reduction of production costs in ECO (-15%) does not compensate for the decline in revenue (-19%) leading to a reduction in margins (-21%). In BIO, the higher fruit selling price makes it possible to obtain margins identical to REF. 28% of ECO systems and 50% of BIO are classified Economical and Performant Systems (SCEP, 50% reduction of pesticides and margins above the median). These results show the technical feasibility of a strong reduction of pesticides in peach orchards, which reduces the risks of impacts on the environment and human health. An increase in the price paid to producers (0.15 €/kg of fruit) in ECO systems would be necessary to offset the average decrease in marketable yields in order to promote the transition to these low pesticide use systems.; EcoPêche vise à concevoir et évaluer des vergers de pêche-nectarine conciliant une forte réduction des produits phytopharmaceutiques sans pénalisation des performances technico-économiques. Les expérimentations système, conduits par 8 partenaires dans 7 sites, combinent de nombreux leviers d’action depuis les choix structurels à la plantation jusqu’à l’association de différentes méthodes alternatives pour la gestion annuelle des vergers sur la période 2013-2018. Les analyses de données concernent 29 systèmes x années Référence (REF), 36 ECO (Econome en pesticides) et 12 systèmes BIO. La réduction des produits phytosanitaires hors biocontrôle atteint 52 % dans ECO et 77 % dans BIO par rapport à REF (21,1 IFT). Le rendement commercialisable est plus faible dans ECO (-20 %) et BIO (-64 %) par rapport à REF (30,5 t/ha). La réduction des coûts de production dans ECO (-15 %) ne permet pas de compenser la diminution du chiffre d’affaire (-19 %) conduisant à une réduction des marges (- 21 %). En BIO, le prix de vente plus élevé des fruits permet d’obtenir des marges identiques à REF. 28 % des systèmes ECO et 50 % des BIO sont classés Systèmes Economes et Performants (SCEP, réduction de 50 % des IFT et marges supérieures à la médiane). Ces résultats montrent la faisabilité technique d’une forte réduction des pesticides en pêcher ce qui diminue les risques d’impacts sur l’environnement et la santé humaine. Une augmentation du prix payé aux producteurs (0,15 €/kg fruits) dans les systèmes ECO serait nécessaire pour compenser la diminution moyenne des rendements afin de favoriser la transition vers ces systèmes économes en pesticides. Mots

National audience; CAP ReD vise à concevoir et évaluer des vergers de cerisier, abricotier, prunier d’Ente, prunier américano-japonais et mirabellier, permettant de réduire l’usage des produits phytosanitaires par deux, tout en conservant les performances technicoéconomiques. Les expérimentations systèmes, conduites par 9 partenaires dans 10 sites de 2013 à 2018, combinent de nombreux leviers d’action. Ainsi, 17 systèmes économes en produits phytosanitaires (ECO) sont comparés chaque année à 11 systèmes de référence (PFI). Ces systèmes ECO ont permis une réduction moyenne de 58 % des IFT hors biocontrôle. L’objectif « zéro herbicide » a été atteint dans la majorité des systèmes. Le rendement commercialisable est plus faible dans ECO (− 19 %), sauf dans les systèmes à haute densité ou biaxe d’arbres. Ainsi, le coût de production des systèmes ECO est en moyenne supérieur de 20 %.

International audience; Complete genomic sequences of Artichoke latent virus (ArLV) have been obtained by classical or high-throughput sequencing for an ArLV isolate from Italy (ITBr05) and for two isolates from France (FR37 and FR50). The genome is 8,278 to 8,291 nucleotides long and has a genomic organization comparable with that of Chinese yam necrotic mosaic virus (CYNMV), the only macluravirus fully sequenced to date. The cleavage sites of the viral polyprotein have been tentatively identified by comparison with CYNMV, confirming that macluraviruses are characterized by the absence of a P1 protein, a shorter and N-terminally truncated coat protein (CP). Sequence comparisons firmly place ArLV within the genus Macluravirus, and confirm previous results suggesting that Ranunculus latent virus (RALV), a previously described Macluravirus sp., is very closely related to ArLV. Serological relationships and comparisons of the CP gene and of the partial RaLV sequence available all indicate that RaLV should not be considered as a distinct species but as a strain of ArLV. The results obtained also suggest that the spectrum of currently used ArLV-specific molecular hybridization or polymerase chain reaction detection assays should be improved to cover all isolates and strains in the ArLV species.

Ce numéro est constitué d’articles de synthèse des projets DEPHY EXPE publiés à l’occasion du colloque national DEPHY, qui s’est déroulé les 13 et 14 novembre 2018 à la Cité des Sciences et de l'Industrie (Paris). Nous vous invitons à découvrir le bilan et les enseignements des 21 projets conduits sur la période 2012-2017.; Chicory escarole and artichoke are the main open fields cultivated species in Roussillon. Theirsuccession in rotation has greatly decreased in recent years in favor of a specialization of farms. TheECOLEG project aims to design an innovative system based on rotation chicory escarole / artichoke,including a green manure and solarization to reduce by 50% the use of plant protection products. Themain levers studied are crop rotation, replacement of traditional gravity-fed irrigation with drip irrigationsystem, biodegradable mulching and weekly observation of plots to limit systematic treatments. The useof early-stage biocontrol products was also expected to reduce FTIs. Five years of experimentation ledto a total reduction in the use of chemical herbicides, the cessation of systematic treatments againstaphids and cryptogamic diseases, making it possible to reduce the use of plant protection products bymore than 70%. The results obtained could be partially transferred to the producers of the DEPHYFARM network.; La chicorée scarole et l'artichaut sont les principales espèces cultivées en plein champ en Roussillonmais leur succession en assolement a fortement diminué ces dernières années au profit d'unespécialisation des exploitations sur l’une ou l’autre des cultures. Le projet ECOLEG vise à concevoir unsystème maraicher innovant utilisant peu de produits phytopharmaceutiques. L'objectif est de mettre enplace un système de culture intégrant une rotation chicorée scarole/artichaut, en redéfinissant lesitinéraires techniques, et en y incluant un engrais vert et une solarisation afin de réduire de 50 %l'utilisation des produits phytosanitaires. Les principaux leviers étudiés sont la rotation des cultures, leremplacement de l’irrigation gravitaire traditionnelle par un système de goutte à goutte avec paillagebiodégradable, l’observation hebdomadaire des parcelles pour limiter les traitements systématiques, lerecours aux produits de biocontrôle utilisés préventivement dans la lutte contre le mildiou et ensubstitution des herbicides chimiques. Cinq années d’expérimentation ont été conduites et ont mené àune très forte réduction, voire un arrêt certaines années, de l’utilisation des herbicides chimiques et àl’arrêt des traitements systématiques contre pucerons et maladies cryptogamiques. Ainsi, l’utilisation deproduits phytopharmaceutiques a était réduite de plus de 70 %. Les résultats obtenus ont pu êtrepartiellement transférés chez les producteurs au travers du réseau DEPHY FERME.

The French apricot production is located in the South-Eastern part of the country and focused both in the Rhone valley and close to the Mediterranean Sea. The north of the Rhone valley is characterized by a continental climate while the southern region (Rhone valley and Mediterranean area) is under warm typical Mediterranean climate. Obviously apricot fruit production depends on a specific panel of cultivars in each area of cultivation due to economic and adaptation constraints. In order to enlarge the panel of cultivars to be developed by the growers in each region an integrated breeding program is developed at a national level in France with the participation of INRA, CENTREX and CEP INNOVATION. The main goals of the breeding program are: the elaboration of cultivars suitable for a durable production (including resistance to pests and disease), production regularity (including self-fertility and quality of the flowers), and fruit quality (including taste, attractiveness, and suitability for the transport). The evaluation phase is organized in the 3 main areas of production (Perpignan, Nimes, Valence) and follows 3 complementary evaluation stages (i) observation of the hybrid on its own roots; (ii) evaluation of the best hybrids after grafting in the 3 main areas; (iii) assessment of the agronomic and commercial interest of the 'elite' accessions in small orchards. The main results issued from this program are presented: 8 registered cultivars, 4 new selections under registration, and the first PPV resistant cultivar 'Aramis' ® 'Shamade'.

INRA, CENTREX and CEP INNOVATION are developing new apricot cultivars for French growers with particular attention paid to consumer's expectations. The main objectives of the related breeding programme are: production regularity, fruit quality and attractiveness. Their evaluation is based on a multilocal and pluri-annual set of trials located in the three major French areas of cultivation and organised as a 3-stage-evaluation: (i) observation of the seedlings on their own roots (ii) evaluation of the best grafted selections in the 3 main areas, (iii) assessment of the agronomic and commercial interest of the 'elite' accessions in small commercial orchards. At the end of the selection process two recent main types of cultivars have been introduced: - Ten new cultivars able to enlarge the harvesting season by 'conventional' type of fruit ('Soledane', 'Solimar'@, 'Candide', 'Bergerval'@, 'Bergarouge'®, 'Royal Roussillon', 'Vertige', 'Fantasme'@, 'Helena du Roussillon'®, 'Frisson'); - Three new fruit-type apricots characterized by a stark red blush covering 80% of the fruit shape, developed under the same trademark, 'Rubisco'@ (Ravival, Ravilong and Ravicile).

National audience

International audience

International audience; French apricot production is located in the south-eastern part of the country, with a focused zone in the Rhone valley and close to the Mediterranean Sea. The north of the Rhone valley is characterized by a continental climate, while the southern region ( Rhone valley and Mediterranean area) is under a warm, typically Mediterranean climate. Obviously, apricot fruit production depends on the development of a specific panel of cultivars in each area of cultivation because of economic and adaptation constraints. In order to enlarge the panel of cultivars for growers of each region, an integrated breeding program has been developed at a national level in France with the participation of INRA, Centrex and CEP Innovation. The main goals of the breeding program are: the elaboration of cultivars suitable for durable production ( including resistance to pests and diseases), production regularity ( including self-fertility and quality of the flowers), and fruit quality ( including taste, attractiveness, and suitability for transport). The evaluation phase is organized in the three main French areas of production ( Perpignan, Nimes and Valence) with three complementary evaluation stages: ( i) observation of hybrids on their own roots ( ii) evaluation of pre-selections after grafting in the three main areas, and ( iii) 'elite' agronomic and commercial assessments in small orchards. A tough diagnosis, that includes biological, serological and molecular analysis, is conducted in parallel for assessing resistance to Plum pox virus ( PPV). The main results issued from this program are presented here, with 10 cultivars, including PPV-resistant Aramis (R) cultivars.

International audience

National audience

International audience; Collaborative research was conducted at the INRA Research Centers to assess the microbial control potential of Beauveria bassiana- and Lecanicillium lecanii-based formulations against whiteflies in protected crops under Mediterranean conditions. Four series of small-scale glasshouse trials were performed in 1999 and 2000 in southern France. Two applications at 4-5 day intervals of Naturalis-L and Mycotal were conducted on young larvae of the greenhouse whitefly, Trialeurodes vaporariorum, at rate's recommended by the manufacturers. Because of the expectation that environmental conditions prevailing in Mediterranean greenhouse crops may lead to greater climatic constraints for mycoinsecticide efficacy than in more temperate areas, manipulation of the greenhouse climate has been used to aim at optimizing mycoinsecticide efficacy. The climatic management strategy was mainly based on closing the ridge vents 2 h more at night-time in so-called "humid" glasshouse compartment than in a "dry" one. Thus, the daily period at high humidity (>90% RH) was two or three times longer in the "humid" compartment than in the "dry" one. In spite of this differential, mycoinsecticide treatments reduced numbers of surviving whitefly larvae by >85% in the "humid" compartment as expected as favorable, as well as in the "dry" compartment, expected as unfavorable. The results indicated clearly that both B. bassiana- and L. lecanii-based mycoinsecticides have a strong potential for microbial control of whitefly larvae infesting tomato crops at moderate ambient humidity in Mediterranean glasshouses. Our investigations provided strong arguments for explaining these unexpected results. The RH conditions prevailing in the targeted insect habitat should be greatly disconnected from that of the ambient glasshouse air. We suggest that strategies of mycoinsecticide optimization against phyllophagous insects in protected crops have to take into account factors acting on the leaf transpiration activity. (C) 2003 Elsevier Science (USA). All rights reserved.

International audience; Disease-susceptibility of apricot cultivars is a key-stone towards low-input production systems. Among the main diseases, the susceptibility to Monilinia spp. and leaf rust of apricot cultivars are economically important but rarely assessed. A 5-years study in two sites was conducted to assess the susceptibilities to Monilinia spp. and leaf rust of 16 apricot cultivars under natural conditions (no inoculation). No fungicide and insecticide were applied during the experiment. In Torreilles site, no significant Monilinia spp. was observed. In Gotheron site, the percentage of shoots necrosed by Monilinia spp. ranged from 13% to 100% during 2010-2011. A Genotype x Environment interaction was observed for Monilinia spp. damages. Concurrently a high variability to leaf rust was observed in both sites. The ranking of cultivars susceptibility to leaf rust was similar between both sites

National audience; - Maladie observée lors de printemps humide. - dispositif expérimental abricotier sans protection fongicide. - De très fortes différences de sensibilité à la tavelure. - Tavelure, une maladie à ne pas négliger. - Contournement du gène de résistance Vf

National audience; Les monilioses sur fleur sont une des principales causes d'irrégularité de production en verger d'abricotier. Plusieurs espèces du champignon Monilia sont pathogènes. M. laxa et M. fructigena peuvent infecter les fleurs, les fruits et les pousses des arbres de fruits à noyaux et à pépins. M. furcicola a été observé dans la Vallée du Rhône pour la première fois en 2001.

National audience

International audience

National audience; In France, fruit production is cultivated on 140 thousand hectares, mainly conducted on intensive training system. Very few elements are available on low input training systems while they have to integrate the global rule under the frame of Ecophyto 2018. In order to evaluate if another system of cultivation is possible, a project was developed to highlight the main factors to be integrated in low input training system. A low input multilocal experimental design has thus been investigated on apricot in two main regions of production: Rhone valley and Roussillon. A set of 9 common cultivars with 20 replications each, planted in a complete single-tree randomization design was established. As already observed in apple orchard, a larger set of diseases has been observed in our experimental plots by comparison with conventional training orchards. A large genetic variability was evidenced among the observed cultivars, but if some of them expressed components of resistance against the observed diseases no one appeared widely resistant to all the diseases. Taking in consideration the longevity of the orchard, a huge concern exists with the tested germplasm because the observed dieback was in between 10 and 80% of the trees according to the cultivars after only 6 years of observation. On the methodological point of view, a clear optimization of the experimental design is expected on the base of the observed results.; L’arboriculture française se développe sur près de 140 000 ha (soit 1% de la SAU). Largement conduite dans un contexte non limitant en intrants, elle a peu investi l’étude du comportement sous faible niveau d’intrant et est clairement insuffisamment préparée aux enjeux portés par Ecophyto 2018. Le projet que nous avons conduit visait à appréhender les bases méthodologiques d’une expérimentation sous utilisation réduite de pesticides, afin de cribler au mieux les ressources génétiques en vue de leur utilisation postérieure. Développé sur abricotier dans le cadre d’un dispositif multisite, reposant sur des vergers pièges en randomisation totale, ils ont permis i) de vérifier, comme cela avait déjà pu être fait sur pommier, que les traitements réalisés en conventionnel masquaient des maladies dont on n’aurait pas a priori soupçonné l’existence en verger (tavelure, …), et de préciser leurs modalités d’observation, ii) de mettre en évidence une variabilité génétique très large au sein des ressources « abricotier » et donc de démontrer l’importance du fond génétique dans l’aptitude à une culture sous faible niveau d’intrant, et, son impact potentiel dans les stratégies d’amélioration mises en œuvre, et iii) de démontrer au plan de la méthodologie d’expérimentation que l’étude de la sensibilité à des maladies conduisant au dépérissement du verger (Chancre bactérien, ESFY…), ne pouvait pas être raisonnablement conduite dans des vergers sous faibles niveaux d’intrants, sauf à prendre le risque d’avoir des dispositifs incomplets et inexploitables très rapidement, que le choix de dispositifs en blocs répétés s’avérait une solution pratique et efficiente pour appréhender les effets attendus et la nécessité de dispositifs multilocaux et pluriannuels.

In June 2008, tomato (Solanum lycopersicum L.) plants cv. Fer De Lance (De Ruiter Seeds, Bergschenhoek, the Netherlands) grown in greenhouses near Perpignan (southern France) showed growth reduction and necrotic lesions on fruits, stems, and basal parts of the leaves. Tomato torrado virus (ToTV) was suspected on the basis of symptoms and its recent description in Spain (4). Primer set A (3), designed to ToTV RNA-2, was used for reverse transcription (RT)-PCR experiments on RNA extracted from four infected plants and allowed the amplification of a 493-bp fragment. No amplification was observed from healthy plant extracts. The RT-PCR product was directly sequenced (GQ303330) and a BLAST search in GenBank revealed 99.8- and 99.5%-nt identity with Polish (EU563947) and Spanish type strain (DQ388880) isolates of ToTV, respectively. Double-antibody sandwich-ELISA tests were conducted on these four samples to check for the presence of other viruses commonly found in tomato crops in France. Tomato spotted wilt virus, Parietaria mottle virus, Cucumber mosaic virus, Tomato mosaic virus, and Potato virus Y were not detected but Pepino mosaic virus (PepMV) was detected in all samples. ToTV was mechanically transmitted to Physalis floridana but PepMV was not. This plant was used to inoculate healthy tomatoes that served as a ToTV source for further experiments. Mechanical inoculation to test plants showed that Nicotiana benthamiana, N. clevelandii, N. debneyi, N. glutinosa, Capsicum annuum, Solanum melongena, and some tomato cultivars (including Fer De Lance), in which typical necrotic symptoms were observed, were systemically infected by the virus. Isometric particles ~28 nm in diameter were observed by electron microscopy in crude extracts of infected plants negatively stained with 1% ammonium molybdate, pH 7. To confirm ToTV identification, whitefly transmission experiments were performed with Trialeurodes vaporariorum and Bemisia tabaci. Adult whiteflies were placed in cages with infected tomato plants for 1-, 24-, or 48-h acquisition access periods (AAP) before transferring them by groups of ~50 on susceptible tomato plantlets placed under small containers (six plants per AAP). Forty-eight hours later, plants were treated with an insecticide and transferred to an insect-proof containment growth room. Ten days later, RNA preparation from all plants was tested by RT-PCR for the presence of ToTV. No transmission was observed with a 1-h AAP. With a 24-h AAP, transmission to four of six test plants was observed with both whitefly species, while at 48 h, AAP transmission to three and four plants of six was observed with T. vaporariorum and B. tabaci, respectively. Noninoculated control plants were all negative by RT-PCR. These experiments confirm T. vaporariorum and B. tabaci as natural vectors of ToTV as previously described (1,2). ToTV has been already reported in Spain, Poland, Hungary, and Australia, but to our knowledge, this is the first report of ToTV in France. Our detection of ToTV in April 2009 from the same area revealed 7 positive tomato plants of 17 tested. This observation suggests the persistence of the disease in the Perpignan Region. References: (1) K. Amari et al. Plant Dis. 92:1139, 2008. (2) H. Pospieszny et al. Plant Dis. 91:1364, 2007 (3) J. Van der Heuvel et al. Plant Virus Designated Tomato Torrado Virus. Online publication. World Intellectual Property Organization WO/2006/085749, 2006. (4) M. Verbeek et al. Arch. Virol. 152:881, 2007.

International audience

National audience; L ’abricotier est une des espèces fruitières les plus aisées à conduire en agriculture biologique, étant donné le faible nombre de bioagresseurs à maîtriser dans les conditions de production. Mais le principal d ’entre eux reste le monilia (Monilinia laxa essentiellement)qui constitue une impasse technique majeure,de par la sensibilité de l’espèce aux attaques sur fleurs,rameaux et fruits. Les conditions climatiques à la floraison peuvent entraîner une contamination primaire importante et des pertes de récolte considérables. La levée d ’un tel verrou,tout comme l’analyse objective des risques encourus,permettraient un développement de la production d’abricots biologiques en France, mais les pistes de lutte sont encore limitées.La sensibilité variétale reste l’alternative la plus pertinente à long terme.

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* INRA, Centre d'Avignon, Documentation, Domaine St Paul, Site Agroparc, 84914 Avignon cedex 9 Diffusion du document : INRA, Centre d'Avignon, Documentation, Domaine St Paul, Site Agroparc, 84914 Avignon cedex 9

* INRA Documentation, Domaine St Paul, Site Agroparc, 84914 Avignon cedex 9 Diffusion du document : INRA Documentation, Domaine St Paul, Site Agroparc, 84914 Avignon cedex 9

* INRA Documentation, Domaine St Paul, Site Agroparc, 84914 Avignon cedex 9 Diffusion du document : INRA Documentation, Domaine St Paul, Site Agroparc, 84914 Avignon cedex 9

A 927 bp non-ribosomal fragment was used to assess the genetic variability of the European stone fruit yellows (ESFY) phytoplasma infecting 14 different Prunus species. For this, 175 isolates originating from four different Mediterranean countries were tested by PCR-RFLP analysis with seven restriction enzymes. No polymorphism among the ESFY phytoplasma could be observed but 12 out of 18 restriction sites differed between the homologous fragments of ESFY and apple proliferation (AP) phytoplasmas. An 846 bp fragment of a French ESFY isolate was sequenced, it included the 3'-end of a putative nitroreductase gene, an intergenic region and a truncated open reading frame. This ESFY phytoplasma sequence showed 89.7% identity with the equivalent AP phytoplasma nucleotide sequence (83. 9% identity at the amino acid level). The G+C content of the entire sequence was extremely low (15.4%) and A+T-rich codons were highly preferred in codon usage. In this paper, we report the presence of the ESFY phytoplasma for the first time in Turkey and in five Prunus hosts never reported previously. Our results also indicate that the ESFY phytoplasma isolates affecting various Prunus species are genetically homogenous but can be distinguished from the AP phytoplasma. Therefore, they are likely to represent different taxons.