New data on quarantine pests and pests of the EPPO Alert List
By searching through the literature, the EPPO Secretariat has extracted the following new data concerning quarantine pests and pests included (or formerly included) on the EPPO Alert List, and indicated in bold the situation of the pest concerned using the terms of ISPM 8.
- New records
Tomato yellow leaf curl virus (TYLCV - EPPO A2 List) is reported from Kenya. Surveys were conducted in 2018 in fields in 8 major tomato growing counties in Kenya, and TYLCV was detected in all of these counties. It is noted that leaf curl disease in Kenya is also caused by tomato leaf curl Arusha virus (ToLCArV), tomato leaf curl Uganda virus (ToLCUV) and chickpea chlorotic dwarf virus (CpCDV) (Avedi et al., 2022). Present, not widely distributed.
Xanthomonas oryzae pv. oryzicola (EPPO A1 List) is causing bacterial leaf streak disease of rice in Côte d'Ivoire. In October 2018, typical symptoms were observed in the area of Korhogo. The identity of the pathogen was confirmed by PCR (Diallo et al., 2021). Present, not widely distributed.
- Detailed records
In China, Agrilus mali (Coleoptera: Buprestidae – EPPO Alert List) is causing extensive mortality in wild apple (Malus sieversii) forests in the Tianshan Mountains. It has been hypothesized that it was introduced in the early 1990s into this part of China with infested apple seedlings from Shandong province. However, recent genetic studies comparing A. mali populations from five Chinese provinces (Gansu, Inner Mongolia, Liaoning, Qinghai, and Western Tianshan Mountains in Xinjiang province) concluded that A. mali in the Western Tianshan Mountains has possibly been present in the area for a long period and may not have been introduced recently. It is supposed that the recent outbreaks in the Tianshan Mountains might be resulting from climatic and environmental factors that are weakening apple trees in forests and from poor management in apple orchards (Sun et al., 2022).
In the United Kingdom, chestnut blight caused by Cryphonectria parasitica (EPPO A2 List) was detected for the first time in England in 2011. Surveys conducted in 2017-2018 detected the disease at different sites in Berkshire, Derbyshire, Devon, Dorset and London. Further surveys in 2019-2020 detected C. parasitica in additional sites in Berkshire, Buckinghamshire, Cornwall, Derbyshire, Devon, London, and West Sussex, as well as on the island of Jersey. These surveys showed that C. parasitica still has a limited distribution in England. Studies on 115 isolates also revealed a high diversity in vegetative compatibility groups (VCGs) supporting the hypothesis of multiple introductions of C. parasitica over time (Romon-Ochoa et al, 2022).
In Canada, little cherry virus 1 (Velarivirus, LChV-1 – EU Annexes) was first reported in cherry trees (Prunus avium) in the eastern part of the country. It was detected in Ontario, based on surveys performed in 2014-2018 and is not considered widespread (Simkovich et al., 2021).
In the USA, Raffaelea lauricola (EPPO Alert List) causing laurel wilt has recently been reported from Virginia. In July 2021, a wilted sassafras (Sassafras albidum) sapling tested positive for R. lauricola. It was located close to a county in Tennessee where the disease occurs. Although exit holes were observed, no Xyleborus glabratus (vector of laurel wilt) was found (Gazis et al., 2022).
According to the review of Chinese literature on thrips by Xu & Teulon (2022), Scirtothrips dorsalis (Thysanoptera: Thripidae – EPPO A2 List) is present in the following provinces for which the EPPO Secretariat had no previous records: Beijing, Chongqing, Guizhou, Hubei, Shandong.
- Host plants
In Florida (US), Gymnosporangium clavipes (EPPO A1 List) was found in May 2021 in Crataegus uniflora (Rosaceae) trees which displayed fruit galls. This is the first time that G. clavipes is reported on this host (Urbina et al., 2022).
Sources
Avedi EK, Adediji AO, Kilalo DC, Olubayo FM, Macharia I (2022) Incidence, severity and distribution of yellow leaf curl disease of tomato in Kenya. African Crop Science Journal 30(1), 1-11. https://dx.doi.org/10.4314/acsj.v30i1.1
Diallo A, Zougrana S, Sawadogo M, Kone D, Silué D, Szurek B, Wonni I, Hutin M (2021) First report of bacterial leaf streak disease of rice caused by Xanthomonas oryzae pv. oryzicola in Ivory Coast. Plant Disease 105(12), p 4147.
Gazis R, DeWitt KM, Johnson LK, Chamberlin LA, Kennedy AH, Hansen MA, Bush EA (2022) First report of laurel wilt disease caused by Raffaelea lauricola on sassafras in Virginia. Plant Disease 106(6), 1763. https://doi.org/10.1094/PDIS-11-21-2616-PDN
Romon‐Ochoa P, Kranjec Orlović J, Gorton C, Lewis A, van der Linde S, Pérez‐Sierra A (2022) New detections of chestnut blight in Great Britain during 2019–2020 reveal high Cryphonectria parasitica diversity and limited spread of the disease. Plant Pathology 71(4), 793-804.
Simkovich A, Kohalmi SE, Wang A (2021) First report of little cherry virus 1 infecting sweet cherry in Ontario, Canada. Plant Disease 105(12), p 4173.
Sun H, Jia F, Zhao W, Zhou Z, Li C, Wang J, Yao Y (2022) Population genetics reveals that the Western Tianshan Mountains populations of Agrilus mali (Coleoptera: Buprestidae) may have not been recently introduced. Frontiers in Genetics 13, 857866. https://10.3389/fgene.2022.857866
Urbina H, Jones C, De la Paz A, McVay J (2022) First report of cedar-quince rust Gymnosporangium clavipes on fruit of dwarf hawthorn Crataegus uniflora in Florida, USA. Plant Disease (early view). https://doi.org/10.1094/PDIS-01-22-0027-PDN
Xu B, Teulon DA (2022) Combined searches of Chinese language and English language databases provide more comprehensive data on the distribution of five pest thrips species in China for use in Pest Risk Assessment. Sustainability 14(5), 2920. https://doi.org/10.3390/su14052920