Phytoparasitica (1996) 24, 143-144

Talma Katan, E. Shlevin and J. Katan (1996)
Airborne inoculum of Fusarium oxysporum f.sp. lycopersici in greenhouses of cherry tomatoes
Phytoparasitica 24 (2), 143-144
The 17th Congress of the Israeli Phytopathological Society, February 19-20, 1996 (Bet Dagan, Israel), lecture
Abstract: Plants exhibiting symptoms of wilt and xylem discoloration, which are typical of Fusarium wilt caused by Fusarium oxysporum f.sp. lycopersici (Fol), were observed in greenhouses of cherry tomatoes (cv. 139). Some plants, which were at advanced stages of disease development and desiccation, had their lower stems covered with a thin, light pink layer of macroconidia of F. oxysporum. This sign resembles the sporulating layer on stems of tomato plants infected by F. oxysporum f.sp. radicis-lycopersici (Forl), which causes the crown and root rot disease in tomatoes, and was observed in many greenhouses throughout the country. Monoconidial isolates were used in pathogenicity and vegetative compatibility tests. The isolates were pathogenic on tomato cv. 'Marmande' but not on cv. 'Rehovot-13', thus identifying the pathogen as Fol race 1. The isolates were assigned to vegetative-compatibility group 0030 of Fol. The possibility of coinfection with Fol and Forl was excluded by testing several macroconidia from each plant. Airborne propagules of Fol were trapped on Fusarium-selective medium in greenhouses in which plants with a sporulating layer were growing. The phenomenon was reproduced by inoculating tomato plants (cvs. 139 andMarmande, both susceptible to race 1 of the pathogen) with race 1 of Fol, whereas only certain isolates of race 2 of Fol produced a sporulating layer on artificially inoculated plants. This phenomenon has not been reported previously with Fol and might be connected with specific environmental conditions, e.g. high humidity in the greenhouse, or with certain cultivars. The sporulation of Fol on plant stems and dissemination of macroconidia by air movement may have serious epidemiological consequences. Sanitation of the greenhouse structure, e.g. by space solarization, along with soil disinfestation and other means, is necessary in order to ensure effective disease control.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Jaacov Katan

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution
environment - cropping system/rotation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Fusarium languescens	Tomato (Solanum lycopersicum)	Israel
	Fusarium oxysporum