Definition of black spot in US English:

black spot


  • A disease of plants, especially of roses, producing black blotches on leaves.

    • ‘Neem oil also prevents powdery mildew and black spot.’
    • ‘A soaker hose waters the base of every plant, thereby minimizing black spot and mildew problems that often arise from wetting the leaves.’
    • ‘Some rose varieties are especially prone to black spot and require regular spraying to keep the plants vigorous.’
    • ‘Many popular roses are also susceptible to three fungal diseases, whose names black spot, mildew, and rust are descriptive of their appearance on rose leaves.’
    • ‘To prevent black spot from infecting new plants, spray with a synthetic chemical fungicide once every 10 days, starting in midspring.’


black spot

/ˌblæk ˈspɑt//ˌblak ˈspät/