176 research outputs found
Viruses affecting lentil (Lens culinaris Medik.) in Greece; incidence and genetic variability of Bean leafroll virus and Pea enation mosaic virus
In Greece, lentil (Lens culinaris Medik.) crops are mainly established with non-certified seeds of local landraces, implying high risks for seed transmitted diseases. During April and May of the 2007â2012 growing seasons, surveys were conducted in eight regions of Greece (Attiki, Evros, Fthiotida, Korinthos, Kozani, Larissa, Lefkada and Viotia) to monitor virus incidence in lentil fields. A total of 1216 lentil samples, from plants exhibiting symptoms suggestive of virus infection, were analyzed from 2007 to 2009, using tissue-blot immunoassays (TBIA). Pea seed-borne mosaic virus (PSbMV) overall incidence was 4.9%, followed by Alfalfa mosaic virus (AMV) (2.4%) and Bean yellow mosaic virus (BYMV) (1.0%). When 274 of the samples were tested for the presence of luteoviruses, 38.8% were infected with Bean leafroll virus (BLRV). Since BLRV was not identified in the majority of the samples collected from 2007 to 2009, representative symptomatic plants (360 samples) were collected in further surveys performed from 2010 to 2012 and tested by ELISA. Two viruses prevailed in those samples: BLRV (36.1%) was associated with stunting, yellowing, and reddening symptoms and Pea enation mosaic virus-1 (PEMV-1) (35.0%) was associated with mosaic and mottling symptoms. PSbMV (2.2%), AMV (2.2%), BYMV (3.9%) and CMV (2.8%) were also detected. When the molecular variability was analyzed for representative isolates, collected from the main Greek lentil production areas, five BLRV isolates showed 95% identity for the coat protein (CP) gene and 99% for the 3â end region. Three Greek PEMV isolates co-clustered with an isolate from Germany when their CP sequence was compared with isolates with no mutation in the aphid transmission gene. Overall, limited genetic variability was detected among Greek isolates of BLRV and PEMV
Hot water treatment of Vitis sp. for Xylella fastidiosa
Following a request from the European Commission, the EFSA Panel on Plant Health (PLH) reviewed Italian technical guidelines and the ANSES (Agence nationale de sĂ©curitĂ© sanitaire de lâalimentation, de lâenvironnement et du travail) opinion on the use of hot water treatment (HWT) on Vitis sp. planting material, assessing its efficacy in the elimination of the xylem-invading bacterial pathogen, Xylella fastidiosa. HWT is a robust and reliable technique used to destroy life stages of pests (insects, nematodes) and to inactivate pathogens (phytoplasma, bacteria, fungi) in dormant plant propagation materials (grapevine and other crops). An effective HWT sanitizes the planting material without affecting plant survival and development. For grapevine, HWT to eliminate the Grapevine flavescence dorĂ©e phytoplasma (FD) from planting materials is among the special requirements for the introduction and movement of Vitis sp. to protected zones in the EU. The conditions of 50°C for 45 min, prescribed and recommended to sanitize grapevine planting material against FD, are considered by the Panel to be also effective against X. fastidiosa and its subspecies. Despite uncertainties on variable thermotolerances of the bacteria, a HWT treatment of 50°C for 45 minutes can effectively account for different thermotolerances. It should be noted that the quality of the HWT is subject to the proper application of the operating procedures to guarantee vigorous growth and pathogen freedom of planting material
Pest categorisation of Unaspis citri
The Panel on Plant Health performed a pest categorisation of the citrus snow scale,
Unaspis citri
(Comstock) (Hemiptera: Diaspididae), for the European Union (EU). This is a well-de
fi
ned and
distinguishable species, native to south-eastern Asia, which has spread to many tropical and subtropical
regions.
U. citri
can be a pest of citrus and has been cited on over 28 different species in 16 plant families.
In the EU,
U. citri
occurs in the Azores. There is uncertainty as to whether it occurs in continental
Portugal. Reports of it occurring in Greece and Spain are likely to be invalid and based on interception
records from these countries. An old Italian record is a misidenti
fi
cation.
U. citri
is listed in Annex IIAI of
2000/29/EC as a harmful organism. The international trade of hosts, as either plants for planting, fruit or
cut
fl
owers, provide potential pathways into the EU. However, current EU legislation prohibits the import
of citrus plants for planting from third countries.
U. citri
is mostly con
fi
ned to coastal humid tropical areas
and does not occur in semi-arid areas that are irrigated. Nevertheless, given that it occurs in the Azores
and that there are regional climatic similarities between places where
U. citri
occurs and climates within
the EU, and taking EU host distribution into account,
U. citri
has the potential to establish in the EU,
especially in citrus-growing regions around the Mediterranean where losses in quality and yield of citrus
could occur. Phytosanitary measures are available to inhibit the likelihood of introduction of
U. citri
.
Considering the criteria within the remit of EFSA to assess the status as a potential Union quarantine pest
(QP), or as a potential regulated non-quarantine pest (RNQP),
U. citri
meets the criteria assessed by
EFSA for consideration as a potential Union QP
Pest categorisation of Longidorus diadecturus
The Panel on Plant Health performed a pest categorisation of Longidorus diadecturus (Nematoda: Longidoridae) for the EU. The nematode is a well-defined taxon and was described from Ontario, Canada and later reported from some states in the USA. The nematode is not present in the EU. It is regulated by Council Directive 2000/29/EC, listed in Annex I A I as L. diadecturus Eveleigh and Allen. It is a migratory ectoparasitic nematode species puncturing cells of plant roots thereby able to transmit the nepovirus Peach rosette mosaic virus (PRMV). The pest is found in soil associated with plant species belonging to different families. L. diadecturus is able to cause direct damage to plants, but its main damage is caused by vectoring PRMV. Soil is a potential pathway for this nematode for entry into the EU. The nematode is able to survive adverse conditions, but the virus may not persist inside the nematode for extended periods. Climatic conditions in the EU are similar to those found in the countries where the pest is currently present. Hosts of the nematode (and the associated virus) are, e.g. peaches and grapes; those crops are also widely cultivated in the EU. The nematode only moves short distances (around 1 m) but may be spread with soil moving activities. Measures are available to inhibit entry via soil as such. Entry of the nematode with soil attached to plants for planting that are not regulated is possible. L. diadecturus does satisfy all the criteria that are within the remit of EFSA to assess to be regarded as a potential Union quarantine pest
Pest categorisation of Scirtothrips citri
The Panel on Plant Health performed a pest categorisation of the citrus thrips,
Scirtothrips citri
(Moulton) (Thysanoptera: Thripidae), for the European Union (EU). This is a well-de
fi
ned and
distinguishable species, occurring in North America and Asia. Its precise distribution in Asia is
uncertain.
S. citri
is a pest of citrus and blueberries and has been cited on over 50 different host
species in 33 plant families. Whether all plants reported as hosts are true hosts, allowing population
development of
S. citri
, is uncertain.
S. citri
feeds exclusively on young actively growing foliage and
fruit. It is not known to occur in the EU and is listed in Annex IIAI of 2000/29/EC as a harmful
organism. The international trade of hosts, as either plants for planting or cut
fl
owers, provide
potential pathways into the EU. However, current EU legislation prohibits the import of citrus plants for
planting. Furthermore, measures aimed at the import of plants for planting in a dormant stage (no
young foliage or fruits present) with no soil/growing medium attached, decreases the likelihood of the
pest
â
s entry via other hosts. Considering that there are regional climatic similarities where
S. citri
occurs in the USA with climates in the EU, and taking EU host distribution into account,
S. citri
has the
potential to establish in the EU, especially in citrus and blueberry growing regions around the
Mediterranean where quality losses in citrus and yield losses in blueberry could occur. Phytosanitary
measures are available to inhibit the likelihood of introduction of
S. citri
from infested countries.
Considering the criteria within the remit of EFSA to assess its status as a potential Union quarantine
pest (QP) or as a potential regulated non-quarantine pest (RNQP),
S. citri
meets with no uncertainties
the criteria assessed by EFSA for consideration as a potential Union QP
Pest categorisation of Toxoptera citricida
23The European Commission requested EFSA to conduct a pest categorisation of Toxoptera citricida (Hemiptera: Aphididae), an oligophagous aphid developing and reproducing parthenogenetically on tender leaf and flower flush of citrus (Rutaceae). T.citricida is a taxonomic entity with reliable methods available for detection and identification. It is regulated in the EU by Council Directive 2000/29/EC where it is listed in Annex IIAI as a harmful organism whose introduction and spread into the EU shall be banned. T.citricida is native to tropical regions of Southeast Asia and has spread to most citrus-growing areas worldwide, except California and the Mediterranean basin, causing significant damage to citrus as it is the most efficient vector of the Citrus tristeza virus (CTV). T.citricida occurs in Madeira and, with a restricted distribution, in the north-west of the Iberian Peninsula, mostly on backyard citrus trees. This may have hindered the effectiveness of the official control measures in these areas. There are further phytosanitary measures in place in the EU in order to limit entry via traded commodities. Citrus plants for planting are regulated and are a closed pathway. However, there is uncertainty regarding host status of some non-rutaceous plants on which this aphid has been recorded and so other plant genera may provide additional pathways. The EFSA Plant Health Panelconcludes that the establishment of T.citricida in the main EU citrus growing areas around the Mediterranean would have significant impacts because of its ability to vector CTV. Considering the criteria within the remit of EFSA to assess the status as a potential Union quarantine pest (QP), as a potential protected zone quarantine pest (PZQP) or as a potential regulated non-quarantine pest (RNQP), T.citricida meets with no uncertainties the criteria assessed by EFSA for consideration as a potential Union QP.openopenJeger, Michael; Bragard, Claude; Caffier, David; Candresse, Thierry; Chatzivassiliou, Elisavet; DehnenâSchmutz, Katharina; Gilioli, Gianni; GrĂ©goire, JeanâClaude; Jaques Miret, Josep Anton; Navarro, Maria Navajas; Niere, Björn; Parnell, Stephen; Potting, Roel; Rafoss, Trond; Rossi, Vittorio; Urek, Gregor; Van Bruggen, Ariena; Van der Werf, Wopke; West, Jonathan; Winter, Stephan; Gardi, Ciro; Bergeretti, Filippo; MacLeod, AlanJeger, Michael; Bragard, Claude; Caffier, David; Candresse, Thierry; Chatzivassiliou, Elisavet; Dehnenâschmutz, Katharina; Gilioli, Gianni; GrĂ©goire, Jeanâclaude; Jaques Miret, Josep Anton; Navarro, Maria Navajas; Niere, Björn; Parnell, Stephen; Potting, Roel; Rafoss, Trond; Rossi, Vittorio; Urek, Gregor; Van Bruggen, Ariena; Van der Werf, Wopke; West, Jonathan; Winter, Stephan; Gardi, Ciro; Bergeretti, Filippo; Macleod, Ala
Vitis sp. response to Xylella fastidiosa strain CoDiRO
Following a request from the European Commission, the EFSA Panel on Plant Health assessed a scientific report submitted by the Italian Authorities to the European Commission to support a request to delist Vitissp. from Annex I (âspecified plantsâ) of the Commission Implementing Decision (EU) 2015/789 of 18 May 2015 to prevent the introduction into and the spread within the Union of Xylella fastidiosa (Wells et al.). The report comprised (i) surveys to detect X. fastidiosa in vineyards located in the epidemic zone of CoDiRO with high numbers of diseased olive trees; (ii) inoculation experiments to infect grapevine with a X. fastidiosa isolate âDe Donnoâ from CoDiRO diseased olives; and (iii) vector transmission experiments with X. fastidiosa infective Philaenus spumarius. The Panel acknowledges the difficulties in providing evidence about this hitherto unknown pathogen/vector/host interaction to support the hypothesis that a plant species cannot be infected with a pathogen. Although field surveys to detect X. fastidiosa in grapevine were negative, there was no supporting information on infective vector populations present in the vineyards. Hence absence of infection pressure cannot be excluded. Furthermore the failure to infect grapevine plants either by artificial inoculation or by vector transmission might be due to inoculation conditions not appropriate to induce infections in grapevine. The detection of X. fastidiosa DNA in inoculated grapevine plants even 12 months after inoculation, although localised at the inoculation points, cannot exclude that the DNA amplified by qPCR was from viable cells. The results presented are coherent and provide converging lines of evidence that grapevine (Vitis vinifera) is not a major susceptible host of X. fastidiosa strain CoDiRO. However, from the experimental evidence it is premature to exclude that systemic infections of V.vinifera and Vitissp. occur and that infections at limited foci could serve as a source of inoculum
Pest categorisation of naturallyâspreading psorosis
The EFSA Panelon Plant Health performed a pest categorisation of naturally-spreading psorosis of citrus for the European Union. Naturally-spreading psorosis is poorly defined, because the status of both the disease and its causal agent(s) is uncertain. However, Citrus psorosis virus (CPsV) is a well- characterised Ophiovirus that is systematically associated with the psorosis disease and therefore considered to be its causal agent. Efficient diagnostics are available for CPsV. It is present in at least three EU MS. Naturally-spreading psorosis is currently regulated by Directive 2000/29/EC, while CPsV is not explicitly mentioned in this Directive. CPsV has the potential to enter, establish and spread in the EU territory. However, the main pathway for entry is closed by the existing legislation so that entry is only possible through minor alternative pathways. Plants for planting are the major means of spread while there are uncertainties on the existence and efficiency of a natural spread mechanism. CPsV introduction and spread in the EU would have negative consequences on the EU citrus industry. Of the criteria evaluated by EFSA to qualify as a Union quarantine pest or as a Union regulated non-quarantine pest (RNQP), Naturally-spreading psorosis does not meet the criterion of being a well characterised pest or disease. As it is not explicitly mentioned in the legislation, it is unclear whether CPsV meets the criterion of being currently regulated or under official control. It meets, however, all the RNQP criteria. The key uncertainties of this categorisation concern: (1) the causal role of CPsV in the psorosis disease as well as elements of its biology and epidemiology, (2) the exact nature of the Naturally-spreading psorosis syndrome and the identity of its causal agent and, consequently, (3) whether CPsV should be considered as being covered by the current legislation
Pest categorisation of Botryosphaeria kuwatsukai
The Panel on Plant Health performed a pest categorisation of Botryosphaeria kuwatsukai, the causal
agent of fruit rot and wart bark on apple and pear, for the EU. The pathogen, which was recently
characterised, is a well-defined fungal species affecting mainly Pyrus pyrifolia (Japanese pear),
although Pyrus communis (European pear) and apples (Malus domestica) can also be affected. The
host status of other plant species reported in the literature, i.e. Cydonia oblonga, Chaenomeles
japonica, Malus micromalus, Vitis vinifera and Prunus spp., is unclear. B. kuwatsukai is currently
present in Japan, China, Korea, Taiwan and the USA, and uncertainty exists about its presence in other
areas, where the disease has been associated with other Botryosphaeria spp. The pathogen is not
known to occur in the EU and is listed in Annex IIAI of Directive 2000/29/EC. It could potentially enter
the EU on host plants for planting and fruit originated in infested countries. Climatic conditions in the
EU are suitable for the establishment and spread of the pathogen, as its epidemiology is similar to that
of other Botryosphaeria spp. present in the EU. Pears and apples are widely distributed in the EU. In
the infested areas, B. kuwatsukai causes branch dieback and fruit rot resulting in yield/quality losses.
Its introduction and spread in the EU could impact pear and apple production, although the magnitude
is unknown. Cultural practices and chemical measures may reduce the inoculum sources but cannot
eliminate the pathogen. Phytosanitary measures are available to mitigate the risk of introduction and
spread of the pathogen in the EU. B. kuwatsukai meets all criteria assessed by EFSA for consideration
as a potential Union quarantine pest. As B. kuwatsukai is not known to occur in the EU, this criterion
to consider it as a Union regulated non-quarantine pest is not met
Pest categorisation of Cephalcia lariciphila
The Panel on Plant health performed a pest categorisation of the larch webâspinning sawfly Cephalcia lariciphila (Hymenoptera: Pamphiliidae) for the EU. The insect has been reported in 11 EU Member States (MSs). It is a quarantine pest listed in Annex IIB of Council Directive 2000/29/EC. Protected zones are in place in Ireland and the UK (Northern Ireland, Isle of Man and Jersey). C. lariciphila can feed on all species of the genus Larix. There have been reported outbreaks in the Czech Republic, Germany, the Netherlands and the UK (England and Wales) in plantations of European larch (Larix decidua) and Japanese larch (Larix kaempferi = Larix leptolepis). C. lariciphila is absent in the protected zones. The pest can enter the protected zones by humanâassisted spread or by natural spread from EU areas where the pest is present. Plants for planting are considered the most important pathway for the pest. The pest can establish in the protected zones because the climatic conditions are similar to those of the 11 MSs where C. lariciphila is established, and the pest's main host plants are present. The prepupae overwinter in the litter, the adults emerge during MayâJune, and each female lays 30â40 eggs in slits in mature needles. The larvae feed on the needles through four instars. There is one generation per year; some of the prepupae undergo prolonged diapause for more than 1 year. The impact where the pest occurs is mainly related to the loss of tree growth following defoliation, while tree mortality was locally observed only after repeated defoliation. However, impact is likely to be mitigated by local biological control agents. All criteria assessed by EFSA above for consideration as a potential protected zone quarantine pest and as a potential regulated nonâquarantine pest were met
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