- any of various plant diseases caused by a virus or fungus and characterized by concentric rings of discoloration or necrosis on the leaves.
Origin of ring spot
Examples from the Web for ring spot
Historical Examples of ring spot
The formation of the second ring-spot sometimes takes place in the present stage (Fig. 42).
On the first segment only there is210 no spot, and here no ring-spot is afterwards formed.
At a later period these two222 crescents and also the two primary nuclei coalesce, producing a ring-spot which, as in Fig. 61, Pl.
In this way the first ring-spot probably arose in some species on only one—the penultimate segment.