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Bull. Spec. CORESTA Congress, Manila, 1980, p. 84, P03, ISSN.0525-6240

Influence of fungicide sprays against blue mold on the Mycoflora of green tobacco leaves

DUCOMMUN Ph.; CORBAZ R.
SOTA, Tobacco Research Center, Nyon, Switzerland
The fungicides used were maneb and metalaxyl, sprayed respectively every 10 or 20 days on Burley tobacco. The standard plots did not receive any treatment. Two techniques were used for the analysis of the phylloplane mycoflora : 1) the print and 2) the spore's fall. This for each priming and for both faces of the leaves. The predominant genera were : Cladosporium, Alternaria, Epicoccum, Sporobolomyces, Tilletopsis and Aureobasidium. The total microorganism number was more strongly reduced by maneb than by metalaxyl; with technique number 2 this decrease was even more clear. The following genus were not affected by metalaxyl : Sporobolomyces, Rhodotorula, Tilletiopsis and Torulopsis. The number of Cladosporium colonies suffered a reduction of 70.7% on the upper leaf surface and 55.3% on the under surface by maneb, against 18.7% and 20.8% by metalaxyl.