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Archive for the ‘pest alerts’ Category

 Grahame Jackson/ PestNet

 Sydney NSW, Australia

 For your information

 6 days ago

 0

TAR SPOT, MAIZE – ECUADOR

ProMED
http://www.promedmail.org

Source: Reliefweb, FAO report [summ. Mod.DHA, edited]
https://reliefweb.int/report/ecuador/giews-country-brief-ecuador-15-june-2022
In Ecuador, harvesting of the 2022 main season maize crops is ongoing under favourable weather conditions. Yields are expected to be below average due to low precipitation in key producing provinces. In addition, a fungal disease called tar spot (mancha de asfalto) reportedly affected maize crops, with negative effects on yields.

Communicated by:
ProMED
[Tar spot of maize has been known to lead to serious yield losses of up to 75% in Central and South America. It is considered to be a disease complex involving the synergistic association of at least 3 fungal species: _Phyllachora maydis_, _Microdochium maydis_ (previously _Monographella maydis_) and _Coniothyrium phyllachorae_.

Of these, _P. maydis_ is usually the 1st to cause leaf lesions. While _M. maydis_ is a common benign saprophyte on leaf surfaces, it becomes highly virulent only in association with _P. maydis_ and forms necrotic rings around the _P. maydis_ lesions. _C. phyllachorae_ may be a hyperparasite of the other 2, but its role is not fully understood yet. Leaf lesions may coalesce, causing blight and complete burning of the foliage. In addition, characteristic black shiny spots (“tar spots”) are produced both within lesions and on other leaf areas. Affected ears have fewer kernels which may germinate prematurely on the cob. Weakening of stems may lead to increased lodging. The disease reduces photosynthetic potential and therefore plant vigour.

_P. maydis_ is an obligate parasite; its spores are spread by wind and with infected plant material. It produces a potent toxin killing plant tissue. The disease is favoured by cool, humid conditions. Tar spot management may include fungicide treatments and use of maize varieties with tolerance or low sensitivity to the disease. However, resistance breeding is difficult because of the involvement of multiple pathogens. So far, little is known about the genetics of tar spot resistance.

Maps
Ecuador:
https://www.worldometers.info/img/maps/ecuador_physical_map.gif and
https://images.mapsofworld.com/ecuador/ecuador-political-map.jpg (provinces)
Americas, overview:
https://www.worldofmaps.net/typo3temp/images/karte-nord-und-suedamerika.jpg

Pictures
Tar spot on maize leaves:
https://ipcm.wisc.edu/wp-content/uploads/sites/54/2018/12/IMG_0418.jpg and
https://ag.purdue.edu/btny/cdcruzlab/wp-content/uploads/2020/04/TS16-scaled.jpg
Tar spot symptoms on maize ears:
https://www.canr.msu.edu/corn/uploads/images/Tar%20spot%20on%20ear%20-%20cropped.jpg,
http://i.ytimg.com/vi/ErB9pdiXPp4/maxresdefault.jpg and
https://c1.staticflickr.com/5/4123/4886728754_57fe0982e9_b.jpg

Links
Information on tar spot complex of maize:
https://doi.org/10.1094/PDIS-02-20-0449-FE,
https://www.extension.purdue.edu/extmedia/BP/BP-90-W.pdf,
https://www.agweb.com/news/crops/crop-production/tar-spot-what-you-need-know-about-new-corn-disease,
https://www.researchgate.net/publication/266732736_Tar_Spot_Complex_of_Maize_Facts_and_Actions,
https://doi.org/10.1111/j.1365-3059.1995.tb01671.x,
https://www.youtube.com/watch?v=ErB9pdiXPp4 and
https://www.apsnet.org/publications/phytopathology/backissues/Documents/1992Articles/Phyto82n05_505.PDF
Tar spot information & resources via:
https://www.cimmyt.org/tag/tar-spot-complex/
Recent updates on tar spot in North America:
https://phys.org/news/2022-01-pathologists-collaborate-knowledge-threat-corn.html,
https://www.newfoodmagazine.com/news/161116/plant-pathologists-leading-fight-against-damaging-corn-disease-tar-spot/ and
https://eu.thedailyreporter.com/story/news/2022/02/22/msue-farmer-education-day-focuses-corn-tar-spot-which-hit-michigan/6881223001/
_Phyllachora maydis_ taxonomy:
http://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=167673
_Microdochium maydis_ taxonomy and synonyms:
http://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=811970 and
http://www.speciesfungorum.org/GSD/GSDspecies.asp?RecordID=811970
_Coniothyrium phyllachorae_ taxonomy:
http://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=178431
– Mod.DHA

 Maize

 Tar_spot

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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

In China, Ralstonia syzygii subsp. indonesiensis (EPPO A1 List) was isolated for the first time from wilted tobacco (Nicotiana tabacum). The identity of the bacteria was confirmed by sequencing. This is the first record of this subspecies on tobacco, and the first record of the species in China (Lu et al., 2021).

In Brazil, Zaprionus tuberculatus (Diptera: Drosophilidae – formerly EPPO Alert List) was first recorded in January 2020 in urban parks in Brasilia (Distrito Federal) and in 2021 in several natural reserves around the city. This is the first record of the species in the Americas (Cavalcanti et al., 2021).

  • Detailed records

In the USA, Elsinoë australis (EU Annexes), the causal agent of sweet orange scab, is first reported from Alabama. Two quarantine areas have been established in Baldwin and Mobile counties, respectively (NAPPO, 2021). 

The pest status of Elsinoë australis in the USA is officially declared as: Present: not widely distributed and under official control.

In Western Siberia (RU), Ips amitinus (Coleoptera: Curculionidae: Scolytinae – EU Annexes) was first recorded in 2019 in Tomsk (237 ha) and Kemerovo oblasts (1033 ha), damaging Pinus sibirica (Siberian pine) (EPPO RS 2020/067). Further studies have shown that the pest rapidly spread within Siberian pine forests in Tomsk, Kemerovo, and Novosibirsk oblasts, covering an area of 31 200 km². Considering its spread towards the east, and the fact that I. amitinus successfully colonized P. koraiensis (Korean pine) in an arboretum near Tomsk, the authors noted that I. amitinus might also represent a threat to P. koraiensis in the Russian Far East (Kerchev et al., 2022).

In France, in the framework of the official surveys for potato cyst nematodes, Globodera rostochiensis (EPPO A2 List) was detected in a field of potato (Solanum tuberosum) in Puy-de-Dôme department (Auvergne-Rhônes-Alpes region). Eradication measures are applied (NPPO of France, 2022-05). 

The pest status of Globodera rostochiensis in France is officially declared as: Transient, actionable, under eradication.

In Iran, tomato brown rugose fruit virus (Tobamovirus, ToBRFV – EPPO A2 List) had previously been reported from tomato crops (EPPO RS 2021/235). It has been also reported from symptomatic bell pepper crops (Capsicum sp.) in late December 2021 (Esmaeilzadeh & Koolivand, 2021).

In the United Kingdom, tomato brown rugose fruit virus (Tobamovirus, ToBRFV – EPPO A2 List) was declared eradicated in December 2021 (EPPO RS 2022/018). In May 2022, a new outbreak was confirmed in a tomato production site in the West Midlands which had been first infected in 2020. Eradication measures are applied. 

The pest status of tomato brown rugose fruit virus in the United Kingdom is officially declared as: Present: not widely distributed and under official control.

In Western Australia (AU), Thekopsora minima (EPPO A2 List) was found for the first time in April 2022. This blueberry rust has been found in several locations, including the Perth metropolitan area, Manjimup, and Swan View. In Australia, T. minima is present in New South Wales, Queensland, and Victoria, and is subject to containment measures in Tasmania. In Western Australia, eradication of the disease is not considered feasible (Government of Western Australia, Greenlife Industry Australia, 2022).

Citrus canker caused by Xanthomonas citri pv. citri (EPPO A1 List) was found in a nursery in South Carolina (USA) in February 2022 on Citrus meyeri and Citrus aurantifolia. Eradication measures are applied in the nursery and trace-forward activities are conducted to trace and destroy citrus plants sold to customers in 11 US states (Alabama, California, Florida, Georgia, Louisiana, Mississippi, Nevada, Oregon, South Carolina, Texas, and Washington) (USDA-APHIS, 2022).

  • New pests and taxonomy

The causal agent of a severe needle blight disease observed in New Zealand (Gisborne region, North Island) on Podocarpus totara (Podocarpaceae) has been identified as a new phytophthora species called Phytophthora podocarpi sp. nov. Affected totara trees show needle dieback in the lower crown. Infected needles initially turn khaki in colour, then blacken and fall. Shoot infection causes the needles above the point of infection to turn brown, and as these remain attached, affected trees have a scorched appearance. To-date, the disease has affected a small number of trees and no mortality has been observed (Dobbie et al., 2022).

Sources

Cavalcanti FA, Ribeiro LB, Marins G, Tonelli GS, Báo SN, Yassin A, Tidon R (2021) Geographic expansion of an invasive fly: first record of Zaprionus tuberculatus (Diptera: Drosophilidae) in the Americas. Annals of the Entomological Society of America, saab052. https://doi.org/10.1093/aesa/saab052 

Dobbie K, Scott P, Taylor P, Panda P, Sen D, Dick M, McDougal R (2022) Phytophthora podocarpi sp. nov. from diseased needles and shoots of Podocarpus in New Zealand. Forests 13, 214. https://doi.org/10.3390/f13020214

Esmaeilzadeh F, Koolivand D (2022) First report of tomato brown rugose fruit virus infecting bell pepper in Iran. Journal of Plant Pathology (early view). https://doi.org/10.1007/s42161-022-01094-2

Government of Western Australia (2022-05-16) Blueberry rust: biosecurity alert. https://www.agric.wa.gov.au/plant-biosecurity/blueberry-rust-declared-pest#:~:text=Blueberry%20rust%20

Greenlife Industry Australia (2022) Blueberry rust in Western Australia. https://www.greenlifeindustry.com.au/communications-centre/blueberry-rust-in-western-australia

Kerchev IA, Krivets SA, Bisirova EM, Smirnov NA (2022) Distribution of the small spruce bark beetle Ips amitinus (Eichhoff, 1872) in Western Siberia. Russian Journal of Biological Invasions 13(1), 58–63. https://doi.org/10.1134/S2075111722010076

Lu CH, Li JY, Mi MG, Lin ZL, Jiang N, Gai XT, Jun-Hong M, Lei LP, Xia ZY (2021) Complete genome sequence of Ralstonia syzygii subsp. indonesiensis strain LLRS-1, isolated from wilted tobacco in China. Phytopathology 111(12), 2392-2394.

NAPPO Phytosanitary Pest Alert System. Official Pest Reports. Elsinoë australis (causal agent of Sweet Orange Scab): APHIS adds Baldwin and Mobile Counties in Alabama to the Domestic Quarantine Area (2021-12-17) https://pestalerts.org/official-pest-report/elsino-australis-causal-agent-sweet-orange-scab-aphis-adds-baldwin-and-mobile.

NPPO of France (2022-05).

NPPO of the United Kingdom (2022-05).

USDA-Aphis (2022-03-08) USDA confirms citrus canker in a South Carolina nursery and takes action. https://www.aphis.usda.gov/aphis/ourfocus/planthealth/plant-pest-and-disease-programs/pests-and-diseases/citrus/citrus-canker/citrus-canker

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