Pest categorisation of Anthonomus quadrigibbus

The Panel on Plant Health performed a pest categorisation of the weevil Anthonomus quadrigibbus Say, (Coleoptera: Curculionidae), for the EU. A. quadrigibbus is a well-de fi ned and distinguishable species, recognised as an occasional pest of apples, pears and sour cherries in North America where it also feeds on a range of wild rosaceous plants such as Crataegus and Amelanchier . Adults feed on leaves, fl owers and fruit. Feeding damage to fruit reduces quality. Females oviposit into young fruit, causing surface blemishes and resulting in distortion as the fruit develops. Marketability is subsequently reduced. Larvae and pupae develop within host fruit. Most infested fruit fall prematurely, reducing yield. A. quadrigibbus was regarded as a more serious pest in the early 20th century. A. quadrigibbus is not known to occur in the EU and is listed in Annex IIAI of Council Directive 2000/29/EC under the synonym Tachypterellus quadrigibbus . Host plants for planting and infested fruit could potentially provide a pathway into the EU. Considering the climatic similarities between North America and Europe, and that wild and commercial hosts occur widely within the EU, A. quadrigibbus has the potential to establish within the EU. There would be one generation per year, as in North America. Impacts could be expected in apple, pear and perhaps sour cherry orchards. The level of impacts would be uncertain. There is also uncertainty regarding whether A. quadrigibbus would extend its host range to include other Rosaceae within the EU. Phytosanitary measures are available to reduce the likelihood of introduction of A. quadrigibbus . All criteria assessed by EFSA for consideration as a potential Union quarantine pest are met. As A. quadrigibbus is not known to occur in the EU, this criterion assessed by EFSA to consider it as a Union regulated non-quarantine pest is not met

Pest categorisation of Gymnosporangium spp. (non-EU)

Following a request from the European Commission, the EFSA Panel on Plant Health performed a pest categorisation of Gymnosporangium spp. (non-EU), a well-defined and distinguishable group of fungal plant pathogens of the family Pucciniaceae affecting woody species. Many different Gymnosporangium species are recognised, of which at least 14 species are considered not to be native in the European Union. All the non-EU Gymnosporangium species are not known to be present in the EU and are regulated in Council Directive 2000/29/EC (Annex IAI) as harmful organisms whose introduction into the EU is banned. Gymnosporangium spp. are biotrophic obligate plant pathogens. These rust fungi are heteroecious as they require Juniperus, Libocedrus, Callitropsis, Chamaecyparis or Cupressus (telial hosts) and rosaceous plants of subfamily Pomoideae (aecial hosts) to complete their life cycle. The pathogens could enter the EU via host plants for planting (including artificially dwarfed woody plants) and cut branches. They could establish in the EU, as climatic conditions are favourable and hosts are common. They would be able to spread following establishment by movement of host plants for planting and cut branches, as well as by natural dispersal. Should Gymnosporangium spp. (non-EU) be introduced in the EU, impacts can be expected in orchards, ornamental trees and nurseries. On telial hosts, these pathogens cause galls on stems, twigs and branches, and fusiform swellings on stems. Foliar infections on aecial hosts may lead to severe defoliations. The main knowledge gap concerns the limited available information on the biology, distribution range and impact of several non-EU Gymnosporangium spp. The criteria assessed by the Panel for consideration of Gymnosporangium spp. (non-EU) as potential quarantine pests are met, while, for regulated non-quarantine pests, the criterion on the pest presence in the EU is not met

Effectiveness of in planta control measures for Xylella fastidiosa

This opinion updates the information included in the previous EFSA Scientific Opinion concerning the in planta control measures for Xylella fastidiosa, with a systematic review and critical analysis of the potential treatment solutions that have been published against this pest so far. The output of this opinion focuses on the application of chemical or biological treatments on living plants. In vitro studies, hot water treatments, use of resistant varieties and vector control are excluded from the review. The use of antibiotics is not considered due to the risk of antimicrobial resistance development. The use of weakly virulent or avirulent strains of X. fastidiosa is covered in this review, although this organism is an EU quarantine plant pest and its introduction in the EU territory is banned. Experiments were recently conducted to assess the effect of application of zinc, copper, and citric acid biocomplex, of N-acetylcysteine, and of ‘diffusible signal factor’ (and of its homologs). Their results showed that these control measures were sometimes able to reduce symptoms caused by X. fastidiosa. Recent experiments also showed that several species of endophytic microorganisms, some bacteriophages and inoculation of weakly virulent/avirulent strains of X. fastidiosa could offer some protection against the Pierce’s disease. However, based on the reviewed results, the Panel concludes that, although several published experiments show some effects in reducing symptoms development, the tested control measures are not able to completely eliminate X. fastidiosa from diseased plants. The Panel confirms as previously stated that there is currently no control measure available to eliminate the bacteria from a diseased plant in open field conditions

Treatment solutions to cure Xylella fastidiosa diseased plants

This opinion addresses the question of the efficacy of current treatment solutions to cure Xylella fastidiosa diseased plants, and discusses the experimental treatments under evaluation by two research groups in Apulian olive orchards infected by strain CoDiRO (Complesso del Disseccamento Rapido dell'Olivo). The increasing problems from newly emerging vascular bacterial diseases and the limited success to cure plants from such infections have stimulated numerous studies on treatments with chemical and biological compounds. Under field conditions, various formulations of copper and zinc as spray or root drench are currently used while further options, for example the application of bioactive substances, are at an experimental stage. In Apulia, preliminary results from intensive treatments with such formulations, in combination with the use of good crop management practices, reported more vigorous new growth of diseased trees. However, results provided so far confirmed the continued presence of X. fastidiosa after the treatments under evaluation. This is in agreement with current knowledge that there are no means to cure plants from this bacterial disease, in the sense of eliminating the pathogen from plant tissues. The reported positive response of the treated olive trees is most probably due to the effect of micronutrients and other bioactive compounds that, together with soil cultivation and agronomical practices, improve the vigour of the plants and their resilience to stress caused by bacterial infections. Notwithstanding the preliminary status of these findings, the Panel acknowledged the potentially positive effects of such treatments in prolonging the productive phase of olive trees and their putative relevance for the management of olive orchards, particularly in the containment area where eradication of the pathogen is considered no longer possible. The Panel also concluded that long-term studies are needed to confirm that the reported positive effects on crop performance can be sustained over many years

Pest categorisation of the Andean Potato Weevil (APW) complex (Coleoptera: Curculionidae)

The EFSA Panel on Plant Health performed a pest categorisation of the species within the Andean Potato Weevil (APW) complex (Coleoptera: Curculionidae) for the EU. The complex consists of 14 species, 12 belong to the genus Premnotrypes, plus Phyrdenus muriceus and Rhigopsidius tucumanus. These weevils co-occur in the Andean region, usually above 2,100 m. Eggs are deposited in plant debris close to potato plants. Upon hatching larvae immediately bore into potato tubers where they complete development. Except for R. tucumanus, which pupates inside the tuber, mature larvae leave the tuber and pupate in the soil. Adults can survive feeding on different plants but cannot deposit fertile eggs unless fed on potato foliage. P. muriceus can also complete development feeding on tomato and eggplant roots and occurs at lower altitudes from southern USA to central Argentina. Within the APW complex only species in the genus Premnotrypes are regulated in Annex IIA of Commission Implementing Regulation 2019/2072 as Premnotrypes spp. (non-EU). Within this regulation potential pathways, such as solanaceous plants for planting with foliage and growing medium, seed and ware potatoes, and soil, can be considered as closed. There are no records of interception of any of these weevils in EUROPHYT. Should these species be introduced into the EU, climatic conditions and wide availability of potato crops in the EU territory would provide conditions for establishment, spread and economic impact. Phytosanitary measures are available to reduce the likelihood of entry. The species within the APW complex satisfy with no uncertainties the criteria that are within the remit of EFSA to assess, for them to be regarded as potential Union quarantine pests. Although human-assisted movement of seed potatoes is considered the main mechanism for spread of these species, these weevils do not meet the criterion of occurring in the EU for them to be regarded as potential Union regulated non-quarantine pests

Pest categorisation of Spodoptera eridania

The EFSA Panel on Plant Health performed a pest categorisation of Spodoptera eridania (Lepidoptera: Noctuidae) for the European Union (EU). S. eridania (southern armyworm) is a highly polyphagous pest native to the Americas which has spread to Africa being first reported there in 2016. There are multiple generations per year. Although it can endure short freezing periods, prolonged frosts are lethal. Eggs are laid in batches on the leaves of host plants. Five to seven larval instars follow. Like other armyworms, early instars are gregarious and cause leaf skeletonisation. Older instars disperse and become more solitary and nocturnal. Larvae feed on field vegetables and can bore into tomato fruit. They can eat apical portions of branches and can bore into stems and tubers if preferred foods are scarce. Pupation takes place in the soil. S. eridania is regulated in the EU by Directive 2000/29/EC (Annex IAI). Within this Directive, a prohibition of soil imported from countries where S. eridania occurs, prevents the entry of S. eridania pupae. However, immature stages on plants (excluding seeds), fruit and flowers provide potential pathways for entry into the EU. S. eridania adults have been intercepted in the EU as hitchhikers. Climatic conditions and the wide availability of host plants provide conditions to support establishment in frost-free regions of the EU. It could spread more widely forming transient populations during summer months. Impacts on field vegetables and ornamentals would be possible. Phytosanitary measures are available to reduce the likelihood of entry. S. eridania satisfies the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest. S. eridania does not meet the criteria of (a) occurring in the EU, and (b) plants for planting being the principal means of spread for it to be regarded as a potential Union regulated non-quarantine pest

Pest categorisation of Saperda tridentata

The EFSA Panel on Plant Health (PLHP) performed a pest categorisation of Saperda tridentata (Coleoptera: Cerambycidae) for the EU. S. tridentata (elm borer) occurs in eastern North America. Ulmus americana and U. rubra are almost exclusively reported as hosts, apart from two 19th century records from the USA of larvae from Acer sp. and Populus sp. The Panel does not exclude the possibility of a post‐entry shift in host range to European Ulmus or Acer and Populus. S. tridentata infests trees that are already weakened, and severe infestations can result in tree death. S. tridentata occurs across a range of climate types in North America that occur also in Europe. Between 2016 and 2019, S. tridentata larvae were intercepted with North American Ulmus logs imported into the EU. In the EU, American Ulmus species are mainly found in arboreta and as ornamental specimen trees. If only North American Ulmus are hosts, establishment is unlikely. However, if European Ulmus, Populus or Acer species become hosts, establishment is much more likely, with impact confined to already weakened trees. The information currently available on geographical distribution, biology, impact and potential entry pathways of S. tridentata has been evaluated against the criteria for it to qualify as potential Union quarantine pest or as Union regulated non‐quarantine pest (RNQP). Since the pest is not reported in EU, it does not meet the criteria assessed by EFSA to qualify as potential Union RNQP. S. tridentata satisfies the criterion for quarantine pest regarding entry into the EU territory. Due to the scarcity of data, the Panel is unable to conclude if S. tridentata meets the post‐entry criteria of establishment, spread and potential impact

Pest categorisation of Ripersiella hibisci

The EFSA Panel on Plant Health performed a pest categorisation of Ripersiella hibisci (Hemiptera: Rhizoecidae) for the EU. R. hibisci occurs in Japan, China and Taiwan and has spread to the USA: Florida, Hawaii and the territory of Puerto Rico. R. hibisci is a polyphagous mealybug recorded feeding on roots of monocotyledonous and dicotyledonous plants. Root damage reduces nutrient and water uptake, retards plant growth and may cause leaves to wilt or discolour, heavily infested plants can die. Literature most commonly refers to damage to greenhouse grown potted ornamentals such as Cuphea, Hibiscus, Pelargonium and Phoenix. All life stages occur in the soil and host plants for planting with growing media provide a pathway for eggs, nymphs and adults. Multiple overlapping generations occur in greenhouses each year. R. hibisci is listed in Annex IIA of EU Regulation 2016/2031, appearing with the synonym Rhizoecus hibisci. All plants for planting from third countries are regulated. The import of soil or growing medium attached to plants for planting from third countries (other than Switzerland) is prohibited and therefore reduces the likelihood, but does not prevent entry of R. hibisci, as individuals may remain attached to the roots. There have been interceptions of R. hibisci in the EU, usually on artificially dwarfed plants, i.e. bonsai/penjing. Findings in EU greenhouses have been eradicated. R. hibisci would be able to establish in the EU, greenhouse potted plant production would be most affected. Phytosanitary measures are available to lower the likelihood of introduction. R. hibisci satisfies the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest. R. hibisci does not meet the criterion of occurring in the EU for it to be regarded as a potential Union regulated non‐quarantine pest

Pest categorisation of Pseudocercospora pini-densiflorae

Following a request from the European Commission, the EFSA Plant Health (PLH) Panel performed a pest categorisation of Pseudocercospora pini-densiflorae, a well-defined and distinguishable fungal species of the family Mycosphaerellaceae. The regulated harmful organism is the anamorph Cercoseptoria pini-densiflorae (synonym Cercospora pini-densiflorae) with the corresponding teleomorph Mycosphaerella gibsonii. P. pini-densiflorae causes a needle blight of Pinus spp. also known as Cercospora blight of pines or Cercospora needle blight. P. pini-densiflorae is reported from sub-Saharan Africa, Central and South America, Asia and Oceania, but not from the EU. The pathogen is regulated in Council Directive 2000/29/EC (Annex IIAI) as a quarantine organism whose introduction into the EU is banned on plants (other than fruit and seeds) and wood of Pinus. The pest could enter the EU via plants for planting and other means (uncleaned seed, cut branches of pine trees, isolated bark, growing media accompanying plants, and mycorrhizal soil inocula). Hosts are widespread in the EU and favourable climatic conditions are present in Mediterranean countries. Pinus halepensis, Pinus nigra, Pinus pinea, Pinus pinaster and Pinus sylvestris are reported to be highly susceptible to the pathogen. The pest would be able to spread following establishment after introduction in the EU mainly on infected plants for planting. The pest introduction could have impacts in nurseries and young plantations. Cleaning seeds from needles and removing infected seedlings and pine litter from affected nurseries can reduce the risk of establishment in nurseries and of spread from nurseries to forests, especially given the limited scale of splash dispersal. The main knowledge gaps concern (i) the role of means of entry/spread other than plants for planting and (ii) the potential consequences in mature tree plantations and forests. The criteria assessed by the Panel for consideration as potential quarantine pest are met. For regulated nonquarantine pests, the criterion on the pest presence in the EU is not met