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Swiss Chard

Beta vulgaris L. var. cicla L.

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Symptoms induced in controlled conditions (fumigation with ozone)

cv. Amarilla de Lyon

Ozone symptoms onset appears on the old leaves (Photo A). Leaves are dotted with yellowish internervial stipple (B, C and D). The adaxial surface of the injured areas is eroded and shows the same colour during whole ozone exposure. Finally, the leaf becomes chlorotic because lesions increase or link among them.

cv. Fordhook Giant

First symptoms induced by ozone appear in the apex of the oldest leaves as a yellowish well delimited stipple (D and E) without injuries on the main vein (B). Along all ozone exposure period, injured area increases and is not as well delimited as the beginning (A). The leaf becomes chlorotic and senescent. Young plants can develop ozone symptoms as similar as those induced in old leaves (C).

Symptoms observed in the field

In spring of 2006, ozone-like symptoms were observed in the commercial field of swiss chard in Castelló province (Valencian Community, Spain). Lesions observed were quite similar to those induced in cultivar Amarilla de Lyon in controlled conditions.

© 2009 Fundación CEAM © 2009 Copyright of the photos: their authors