ISHS Acta Horticulturae 354: I International Workshop on Carrot
DONNEES RECENTES SUR LE CAVITY-SPOT DE LA CAROTTE EN FRANCE |
| Authors: | D. Breton, F. Rouxel |
| Abstract:
Cavity-spot is the most seriuos problem affecting carrot-growing in France today. The disease, which results in necosis of the roots during the growing phase, is caused primarily by Pythium violae (MONFRORT et ROUXEL, 1988). Nonnetheless, more recent works suggest the involvement of other species of Pythium (WHITE, 1989). Samples showing symptoms of cavity spot were taken in the region of Nantes and in the various carrot-growing regions of Lower Normandy during the last two seasons. Using a selective medium, samples of Pythium sp were siolated for characterization of their morphological, biological and biochemical aspects. The isolation frequency of the species is thus defined: P. violae is the most frequent cause of the disease, but P. sulcatum, P. sylvaticum and P. intermedium are also causes. Through the use of metalaxyl, significant progress has been achieved, but the varying degrees of sensitivity to this agnt exhibited by P. violae and P. sulcatum will jeopardize the continued effectivenes of chemical control of the disease. Ultimately efforts will have to be directed at developing integrated control. | |
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