Phytopathologia Mediterranea (1999) 38, 76-88

V. Rossi (1999)
Effect of host resistance and fungicide sprays against Cercospora leaf spot in different sugar beet-growing areas of the Mediterranean basin
Phytopathologia Mediterranea 38 (2), 76-88
Abstract: Data on the effect of host resistance and fungicide sprays on Cercospora leaf spot in sugarbeet were gathered from several experimental trials, carried out at 22 locations in the Mediterranean area, under the auspices of the I.I.R.B. (International Institute for Beet Research). The experiments were carried out over a three-year period (1994-1996) in Greece, Italy, Morocco, Spain, and Turkey, under different epidemiological conditions, following a common experimental design: host resistance was considered at five levels corresponding to different cvs, from susceptible to highly resistant; fungicides were included at two levels, sprayed or unsprayed. Host resistance significantly reduced disease progress at locations with severe or moderate epidemics, where the area under disease progress curve (AUDPC) of the most resistant cvs was less than one half and less than one third respectively compared to that of the most susceptible cv. However, host resistance was not a significant factor when mild epidemics occurred. The disease rating of cvs based on the AUDPC did not vary significantly among locations, showing that resistance is stable over locations in the Mediterranean area. Gross sugar yield from the resistant cvs was significantly higher than that from the susceptible one, but only in severe epidemics. Purity of the juice was higher in resistant cvs when severe or moderate epidemics occurred. Fungicide sprays on the susceptible cv. reduced disease progress significantly, and increased sugar yield and juice purity during both severe and moderate epidemics; but during mild epidemics the fungicides influenced the sugar yield only because of their secondary effect on powdery mildew and rust. An integration of host resistance and fungicide spraying did not increase sugar yield significantly over that of the sprayed susceptible cv., but it did increase juice purity, especially at locations with severe or moderate epidemics.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Vittorio Rossi

Research topic(s) for pests/diseases/weeds:
resistance/tolerance/defence of host
population dynamics/ epidemiology

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Cercospora beticola		Spain (continental)
	Cercospora beticola	Beet/sugarbeet (Beta vulgaris)	Greece
	Cercospora beticola	Beet/sugarbeet (Beta vulgaris)	Italy
	Cercospora beticola	Beet/sugarbeet (Beta vulgaris)	Turkey
	Cercospora beticola	Beet/sugarbeet (Beta vulgaris)	Morocco