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Rose Grey Mould


Rose Grey Mould

Usually appear in

All Year

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Caused By:-     The fungus Botrytis cinerea


Rose Gray Mould is a common disease of hundreds of plants. It is especially problematic during periods of high rainfall and cool temperatures. It is caused by the fungus Botrytis cinerea.
This is a fungus that can grow on both the living and the dead plant material.
There are several species of the fungus Botrytis, but the most common is Botrytis cinerea.
It appears as a gray mould, which is producing spores that will be blown onto other plants It is seen on old and dying leaves, stems, seeds, seedlings, bulbs, buds and flowers. It begins as water-soaked spots, where the fungus has invaded the plant cells and eventually develops into the characteristic gray, fuzzy coating. Later in the year resting black spores (Sclerotia) is produced usually on dead plant materials, which can survive the winter and re-infect plants the following year.
Picture by Petr Kapitola, State Phytosanitary Administration,
See these other Grey Moulds and Botrytis fungi Bean Chocolate Spot, Botrytis, Grey Mould, Lettuce Grey Mould, Lily Disease, Onion Neck Rot, Peony Wilt, Snowdrop Grey Mould, Strawberry Grey Mould.


Controlling this fungus is often difficult as it is so widespread so prevention is better than a cure.
Practice sanitation every Autumn. Affected areas of the plants should be cut out, cut stalks at or below the ground level, and destroy or discard infected plant debris.
Air circulation and sun penetration is a very good way to prevent this fungus from getting a hold. Therefore prune to achieve this. Avoid overhead watering, syringing, or misting plants in cool weather.
Spraying with a fungicide is often not successful, but I have found that Scotts Rose Clear gives some control. Several sprayings over a long period may be necessary. Systemic fungicide is often necessary as the fungus can live in the tissue of the plant and can cause branch die back.
Soil sterilants like Armillatox or Jayes fluid can be used on soil in winter to kill the sclerotia or as a greenhouse sterilant.

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