black ring

black ring

[′blak ‚riŋ]
(plant pathology)
A virus disease of cabbage and other members of the family Cruciferae characterized by dark necrotic and often sunken rings on the surface of the leaf.
A virus disease of the tomato characterized in the early stage by small black rings on young leaves.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in classic literature ?
I observed, however, that he was a "Keshla" or ringed man; that is, he wore on his head the black ring, made of a species of gum polished with fat and worked up in the hair, which is usually assumed by Zulus on attaining a certain age or dignity.
Once again Gilbert had lodged three arrows in the white; Tepus came second with two in the white and one in the black ring next to it; but stout Clifton had gone down and Hubert of Suffolk had taken the third place, for, while both those two good yeomen had lodged two in the white, Clifton had lost one shot upon the fourth ring, and Hubert came in with one in the third.
She was perceptibly thinner, and there were black rings under her eyes.
By daylight, Jurgis was able to observe that the color on her cheeks was not the old natural one of abounding health; her complexion was in reality a parchment yellow, and there were black rings under her eyes.
After catching the ball, the robot searched for the black ring using its color sensor.
It looked like a flaming orange, yellow and black ring.
Scientists on Wednesday revealed the first image ever made of a black hole, depicting a fiery orange and black ring of gravity-twisted light swirling around the edges of the abyss.Assembling data gathered by eight radio telescopes around the world, astronomers captured a picture of the hot, shadowy edges of a supermassive black hole, the light-sucking monsters of the universe theorized by Einstein more than a century ago and confirmed by observations for decades.
Prince Harry has been seen wearing a mysterious black ring on his right hand during his ongoing tour of Australia.
A fisheries worker said: "He was tying the cod end rope that holds the net closed and the black ring sea snake was in there.
SKRIPAL would kiss a black ring with the figure of a wolf on it before telling taxi drivers: "I'm a Russian spy," a cab-firm boss revealed yesterday.