Disease note describing the first recording of powdery scab on potatoes in Malta.peer-reviewe

Mifsud, David

Porta-Puglia, Angelo

English

OAR@UM

Journal of Plant Pathology (2006), 88 (2),225-229 227 DISEASE NOTE FIRST RECORD OF POWDERY SCAB CAUSED BY SPONGOSPORA SUBTERRANEA SUBSP. SUBTERRANEA ON POTATO IN MALTA A. Porta-Puglia and D. Mifsud Ministry for Rural A//airs and the Environment, Department 0/ Plant Health, Agricultural Research & Development Centre, Ghammierz; Marsa CMR 01, Malta Potato (Solanum tuberosum L.) is a major crop in Mal-ta. Spongospora subterranea (Wallr.) Lagerh. f.sp. subter-ranea Tomlinson (Sss), agent of powdery scab, affects the quality of the crop and can transmit Potato mop-top virus. In April 2005, powdery scab was observed at harvest on tubers of potato cv Derby in a field at Qrendi. The symp-toms ranged from mild (typical) to extremely severe, mimicking wart disease. Histological observations dis-closed the presence of Sss cystosori and excluded that of the wart organism. The identification of the fungus was confirmed by the one-step assay based on lateral-flow im-munochromatography, using monoclonal antibodies spe-cific for 5. subterranea (AgriStrip kit, BIOREBA AG, Reinach, Switzerland). Pathogenicity was tested on toma-to seedlings (Merz, 1989). To this aim, tomato F1 Torna-do (SEMO, Smidice, Czech Republic) plants were grown from seed on river sand watered with nutrient so-lution. Three weeks after sowing, the roots were trimmed to 40 mm, and the plants were transferred to nutrient so-lution. After one week, the roots of eight seedlings were exposed for three days to a water suspension of cystosori (3x103mP) scraped from tuber scab lesions and main-tained for three days at 15°C in the dark. Eight control seedlings were treated in the same way with sterile nutri-ent solution. The plants were transferred to glass tubes containing nutrient solution kept at 15±2°C and 15h photoperiod (daylight plus fluorescent white-light) for seven days and their roots were then stained and ob-served under the microscope. Zoosporangia of 5. subter-ranea were detected in root hairs and epidermal cells of all inoculated seedlings, whereas the roots of the controls were zoosporangia-free. This is the first record of Sss from the Maltese Archipelago. Temperatures cooler than normal that occurred in autumn and winter 2004-2005 may have favoured the powdery scab outbreak. Merz u., 1989. Infectivity, inoculum density and germination of Spongospora subterranea resting spores: a solution-culture test system. Bulletin OEPPIEPPO Bulletin 19: 585-592. Corresponding author: A. Porta-Puglia Fax: +356.25.904211 E-mail: porta@euroweb.net.mt Received 23 February, 2006 Accepted 16 March, 2006 

Infectivity, inoculum density and germination of Spongospora subterranea resting spores: a solution-culture test system.

Porta-Puglia Fax: +356.25.904211 E-mail: porta@euroweb.net.mt

First record of powdery scab caused by Spongospora subterranea subsp. subterranea on potato in Malta

https://www.um.edu.mt/library/oar/bitstream/handle/123456789/12975/Porta-Puglia%20_%20Mifsud%20-%202006b.pdf?sequence=1&isAllowed=y

First record of powdery scab caused by Spongospora subterranea subsp. subterranea on potato in Malta

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