OBSERVATIONS ON THE SUSCEPTIBILITY OF SOME WILD SPECIES OF THE GENUS NICOTINA AND OF SOME VARIETIES OF NICOTIANA TABACUM L. AND N. RUSTICA L. TO BLUE MOULD (PERONOSPORA TABACINA ADAM) -- PULAWY 1962
ARMY BIOLOGICAL LABS FREDERICK MD
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The course of the blue mould epidemic is affected by atmospheric conditions, as was established in 1961. It was established, on the basis of the observations in 1962 and previously in 1961 that, under the same conditions, not all of the species and varieties of the studied material were equally susceptible to blue mould, as witnessed by the differences in the degree of infection and percentage of diseased plants. Among the wild species of Nicotiana, no manifestations of the mould were observed on the species of N. debneyi and N. exigua. Very weak symptoms appeared in N. paniculata and N. plumbaginifolia. In the group of cigarette-tobacco varieties only the Hicks Resistant and Hicks fixed A2 varieties of Australian origin, obtained by the cross-breeding of N. tabacum and N. debneyi -- 19 proved free of the mould. Like in 1961, the group of oriental tobaccos appeared less susceptible, and most strongly infected were the varieties of the Aurea type.