Could someone explain why mold on my quinces grows in well separated circles around a center? To make clear, what I mean I post the picture enter image description here

  • $\begingroup$ Somewhat related to fairy rings? $\endgroup$
    – md2perpe
    Sep 26, 2020 at 13:32

1 Answer 1


Looks like you may have Monilinia fructigena, brown rot, or at something similar (possibly also called brown rot, but from a different species). This pattern isn't special to quince, but to this fungus.

The formation of these rings is called "zonation", and the concentric rings are from areas of growth that are primarily spore-forming versus not.

Hall (1933) gives an extensive description of the different factors necessary for observing this growth pattern, but ultimately the key factor is light. Patterns of light-and-dark conditions while the fungus spreads causes alternating phases of growth, with one phase comprised of more sporulation.

Another source: https://www.cabi.org/isc/datasheet/34747

Byrde, R. J. W., & Willetts, H. J. (2013). The brown rot fungi of fruit: their biology and control. Elsevier.

Hall, M. P. (1933). An analysis of the factors controlling the growth form of certain fungi, with especial reference to Sclerotinia (Monilia) fructigena. Annals of Botany, 47(187), 543-578.

  • $\begingroup$ Thank you for your answer, I have no access to the publications, which are not online. Is it possible that the factor light means just day and night? $\endgroup$
    – trula
    Sep 26, 2020 at 11:22
  • 2
    $\begingroup$ @trula Yes, day and night. $\endgroup$
    – Bryan Krause
    Sep 26, 2020 at 12:09
  • $\begingroup$ thank you again $\endgroup$
    – trula
    Sep 29, 2020 at 18:02

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