Efficacy of a postharvest treatment aiming at eradication of all developmental stages of Tecia solanivora in ware potatoes.

The European Commission requested the EFSA Panel on Plant Health to prepare and deliver a scientific opinion on the efficacy of a postharvest treatment aiming to eradicate all developmental stages of Guatemalan potato tuber moth Tecia solanivora (Lepidoptera: Gelechiidae) in ware potatoes. The Panel evaluated the scientific publication describing the elevated CO2 treatment, which was defined as: 10-day exposure to 30% CO2, 20% O2 and 50% N2 in controlled atmosphere at 17°C on the variety Negra Yema de Huevo (Papas Antiguas de Canarias, PDO potatoes, Solanum chaucha). In the scientific publication, the treatment was applied under semi-commercial and commercial conditions on artificially and field-infested tubers. The effect of the pest developmental stage on the treatment efficacy was investigated with artificial infestation of potato tubers with eggs, neonate and second instar larvae. Pupae and adults were placed in separate containers during the treatment. However, the third and fourth larval instars were not investigated. Further limitations were the sample size in the experiments, the mortality rate in the control group and the unknown level of infestation of the naturally infested potato tubers. It was not possible to evaluate the degree of pest freedom due to incomplete data on the conditions of production, i.e. the infestation level in the field. The Panel was able to conclude that although no surviving insects were observed in the performed experiments, the statistical evaluation of the presented results from the commercial trial indicate that it cannot be excluded that insects would survive the treatment. For example, based on the data provided the 95% confidence interval of the survival rate for eggs was: 0%-0.453%.

Commodity risk assessment of Prunus domestica plants from Ukraine.

The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as 'High risk plants, plant products and other objects'. This Scientific Opinion covers plant health risks posed by plants of Prunus domestica grafted on Prunus cerasifera imported from Ukraine, taking into account the available scientific information, including the technical information provided by Ukraine. All pests associated with the commodity were evaluated against specific criteria for their relevance for this opinion. One quarantine pest (Lopholeucaspis japonica), two protected zone quarantine pests (Erwinia amylovora and Xanthomonas arboricola pv. pruni) and one non-regulated pest (Eotetranychus prunicola) that fulfilled all relevant criteria were selected for further evaluation. For these four pests, the risk mitigation measures proposed in the technical dossier from Ukraine were evaluated taking into account the possible limiting factors. For the selected pests, an expert judgement is given on the likelihood of pest freedom taking into consideration the risk mitigation measures acting on the pest, including uncertainties associated with the assessment. The degree of pest freedom varies among the pests evaluated, with Xanthomonas arboricola pv. pruni being the pest most frequently expected on the imported plants. The Expert Knowledge Elicitation indicated with 95% certainty that between 9,870 and 10,000 bundles (consisting of 10 plants each) per 10,000 would be free from Xanthomonas arboricola pv. pruni.

Pest categorisation of Melampsora farlowii.

Following a request from the European Commission, the EFSA Panel on Plant Health performed a pest categorisation of Melampsora farlowii, a well-defined and distinguishable fungus of the family Melampsoraceae. M. farlowii is the causal agent of a leaf and twig rust of hemlocks (Tsuga spp.) in eastern North America. The pathogen is regulated in Council Directive 2000/29/EC (Annex IAI) as a harmful organism whose introduction into the EU is banned. M. farlowii is not reported to be present in Europe and could enter the EU via host plants for planting and cut branches. Cones and fruits are listed as plant parts that can carry the pest in trade and transport, but are not regulated. The pathogen could establish in the EU, as climatic conditions are favourable and Tsuga spp. have been planted as ornamentals and in plantations in several EU countries. M. farlowii would be able to spread following establishment by human movement of host plants for planting and cut branches, as well as natural spread. Should the pathogen be introduced in the EU, impacts can be expected on Tsuga spp. plantations, ornamental trees and especially nurseries. Hemlock rust is considered a destructive rust attacking Tsuga spp., particularly Tsuga canadensis in nurseries. The main uncertainties concern whether the impact of the pathogen in plantations under European conditions could be different than observed in eastern North America, whether fruit/cones of Tsuga can be a pathway of entry, and the dissemination potential of the pathogen under European conditions. However, M. farlowii is found in North America in most of the natural distribution range of T. canadensis, suggesting little dispersal limitation of the pathogen. The criteria assessed by the Panel for consideration as a potential quarantine pest are met, whilst, for regulated non-quarantine pests, the criterion on the pest presence in the EU is not met.

Pest categorisation of Cronartium harknessii, Cronartium kurilense and Cronartium sahoanum.

Following a request from the European Commission, the EFSA Panel on Plant Health performed a pest categorisation of Cronartium harknessii, Cronartium kurilense and Cronartium sahoanum, which are well-defined and distinguishable tree fungal pathogens of the family Cronartiaceae. In 2018, these species were moved from the genus Endocronartium to the genus Cronartium. These pathogens are not known to be present in the EU and are regulated in Council Directive 2000/29/EC (Annex IAI) (as non-European Endocronartium spp.) as harmful organisms whose introduction into the EU is banned. These three fungi are autoecious rusts completing their life cycle on Pinus spp. C. harknessii is known as the western gall rust or pine-pine gall rust in North America (Canada, the USA and Mexico). C. kurilense and C. sahoanum are reported from Russia (North Kuril Islands) and Japan. The pathogens could enter the EU via host plants for planting and cut branches. The pathogens could establish in the EU, as climatic conditions are favourable and Pinus spp. are common. The pathogens would be able to spread following establishment by movement of host plants for planting and cut branches, as well as natural spread. Should these pathogens be introduced in the EU, impacts can be expected on pine forests, plantations, ornamental trees and nurseries. The pathogens cause formation of stem galls, which kill young trees and result in stem defect in older trees. The main knowledge gap concerns the limited available information on C. kurilense and C. sahoanum compared to C. harknessii. The criteria assessed by the Panel for consideration of C. harknessii, C. kurilense and C. sahoanum as potential quarantine pests are met, whilst, for regulated non-quarantine pests, the criterion on the pest presence in the EU is not met.

Pest categorisation of Cronartium spp. (non-EU).

Following a request from the European Commission, the EFSA Panel on Plant Health performed a pest categorisation of Cronartium spp. (non-EU), a well-defined and distinguishable group of fungal pathogens of the family Cronartiaceae. There are at least 40 species described within the Cronartium genus, of which two are considered native to the EU (C. gentianeum and C. pini) and one has been introduced in the 19th century (C. ribicola) and is now widespread in the EU - these three species are thus not part of this pest categorisation. In addition, the non-EU C. harknessii, C. kurilense and C. sahoanum were already dealt with in a previous pest categorisation. All the non-EU Cronartium 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. Cronartium spp. are biotrophic obligate plant pathogens. Many of the North American Cronartium species alternate between the aecial host Pinus spp. and telial hosts of various dicotyledonous plants. C. conigenum, C. orientale, C. quercuum and C. strobilinum have different Quercus spp. as their telial hosts. C. orientale and C. quercuum also infect Castanea spp. and Castanopsis spp. The pathogens could enter the EU via host plants for planting and cut flowers and branches. Non-EU Cronartium spp. could establish in the EU, as climatic conditions are favourable to many of them and Pinus and Quercus spp. are common. The pathogens would be able to spread following establishment by movement of host plants, as well as natural spread. Should non-EU Cronartium spp. be introduced in the EU, impacts can be expected on pine, oak and chestnut woodlands, plantations, ornamental trees and nurseries. The Cronartium species present in North America cause important tree diseases. Symptoms on Pinus spp. differ between Cronartium spp., but include galls, cankers, dieback of branches and stems, deformity, tree and cone death. The main knowledge gap concerns the limited available information on (sub)tropical Cronartium spp. The criteria assessed by the Panel for consideration of Cronartium 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.