Scientific Opinion on the risk to plant health of Xanthomonas citri pv. citri and Xanthomonas citri pv. aurantifolii for the EU territory

Abstract

The Panel conducted a pest risk assessment for Xanthomonas campestris (all strains pathogenic to Citrus) for the EU territory and an assessment of the effectiveness of present EU requirements against Xanthomonas strains pathogenic to citrus. The risk assessment was conducted under the scenario of absence of the current specific EU plant health legislation and the assumption that citrus-exporting countries apply measures to reduce yield and quality losses. Risk reduction options were systematically identified and evaluated. The strains of X. campestris pathogenic to citrus have been reclassified as four distinct infraspecific taxa within two species: X. citri and X. alfalfae. Only two pathovars (X. citri pv. citri and X. citri pv. aurantifolii) are responsible for the citrus bacterial canker that presents a major risk for the citrus industry in the EU. Seven entry pathways have been identified and evaluated. The likelihood of entry was rated unlikely for fruit, very likely for fruit plants for planting, moderately likely for ornamental plants for planting and unlikely for leaves and twigs. The uncertainty of probability of entry was rated as high. The probability of establishment was rated as moderately likely to likely with a medium uncertainty because host plants are widely present in EU areas where environmental conditions are suitable. Once established, spread would be likely with a low uncertainty. The impact of the disease, even if control measures are applied, was rated as moderate to major with a medium uncertainty. The disease would cause yield losses in areas where citrus is the main crop, increase the need for control measures and create environmental problems.The combined EU regulations have been shown to be effective in preventing the introduction of X. citri pv. citri or X. citri pv. aurantifolii in the EU, as no outbreaks of citrus canker in the EU territory have been reported. Vernière for the preparatory work on this Scientific Opinion and EFSA staff: Svetla Kozelska, Tilemachos Goumperis and Olaf Mosbach Schulz for the support provided to this Scientific Opinion. Xanthomonas citri pv. citri and Xanthomonas citri pv. aurantifolii pest risk assessment EFSA Journal 2014;12(2):3556 4 Xanthomonas citri pv. citri and Xanthomonas citri pv. aurantifolii pest risk assessment EFSA Journal 2014;12(2):3556 6importance of maintaining the absence of X. citri pv. citri and X. citri pv. aurantifolii in citrusproducing areas and of the risk reduction options to maintain this absence.The effectiveness of current EU phytosanitary measures to reduce the risk of introduction of X. citri pv. citri and X. citri pv. aurantifolii ranges from moderate to high. However, the requirements for buffer zones of pest free production sites in areas infested by X. citri pv. citri or X. citri pv. aurantifolii are insufficiently detailed.The probability of entry of X. citri pv. citri and X. citri pv. aurantifolii via import of plants for planting for citrus production and of ornamental rutaceous plants (species listed in section 3.1...

Pest survey card on Xanthomonas citri pv. citri and pv. aurantifolii

“…When there is free moisture on the lesion surface, bacteria are released and dispersed to new growth by rain splash and windblown rain droplets (EFSA PLH Panel, 2014). When there is free moisture on the lesion surface, bacteria are released and dispersed to new growth by rain splash and windblown rain droplets (EFSA PLH Panel, 2014).…”

“…Temperature, growth stage of plant material, availability of wounds and the amount of inoculum all influence the duration of the latent period (EFSA PLH Panel, 2014;Vernière et al, 2003). Temperature, growth stage of plant material, availability of wounds and the amount of inoculum all influence the duration of the latent period (EFSA PLH Panel, 2014;Vernière et al, 2003).…”

“…aurantifolii for the EU territory (EFSA PLH Panel, 2014), the European and Mediterranean Plant Protection Organisation (EPPO) PM 7/44 diagnostic protocols on Xanthomonas axonopodis pv. citri and Xanthomonas citri pv.…”

Pest categorisation of Xanthomonas oryzae pathovars oryzae and oryzicola

“…BB is associated with the rainy season and is known as a 'post-typhoon' disease as severe epidemics happen after typhoons, because of wind and rain driven dissemination. Such weather conditions do not occur in EU although extreme weather events may happen (strong and violent wind accompanied by intense rains during hot days) (EFSA PLH Panel, 2014).…”

Scientific Opinion on the pest categorisation ofPlenodomus tracheiphilus(Petri) Gruyter, Aveskamp & Verkley [syn.Phoma tracheiphila(Petri) L.A. Kantschaveli & Gikashvili]

“…on citrus propagating material for fruit production grown in EU nurseries are not easily available. Therefore, they were mostly estimated as number of plants based on a 7.5 % rate of tree renewal (Aubert andVullin, 1997):• Greece: 825 813 plants in2006 and 542 300 in 2007(EFSA PLH Panel, 2014b • France: 818 568 plants in(EFSA PLH Panel, 2014b …”