Gray Mould

Gray MouldDisease Description:

A fungus which causes soft watery spots on plant tissue that later become covered in a grayish green mold.

It spreads quickly when the mold forms as it produces many reproductive spores at this stage. A breeze or even a drop of water can release thousands of mold spores to surrounding healthy plant tissue. Including other plants in your collection making controlling this fungus vital.

Symptoms and Damage:

The first signs that the fungus may be present on one of your plants is soft, watery spots on leaf surfaces. The spots will gradually change color from a grayish color to brown and will continue to spread. With the right humidity the fungus will produces spores to reproduce which create a fine fuzz that appears white or gray.

Any disturbance of the fungus after the fuzz appears chances releasing the spores to surrounding plant parts such as the stem and buds. It will also spread to plants near the infected plant.

Fruits and non-woody plants are most likely to suffer from Gray Mold though it is known to attack around 80 commonly grown commercial crops and house plants.

Plant collapse and ultimately death will result from an untreated Gray Mold infection.


Fungi seem to thrive in low temperature and moist environments with little to no airflow. A neutral pH between 6 and 7.5 are also needed, unfortunately this is also the range the most plants find optimal for growth. 

Control and Prevention of Gray Mold

There are many benefits to avoiding chemicals when dealing with plant diseases. The harsh chemicals in some fungicides may cause more harm to an already injured plant not to mention the possible harmful effects to you or your loved ones.

First choices for attempting disease control.

Used when green don't solve the issue.

Only use when blue options have failed and the plant cannot be discarded.

Prevention- Keep plants properly watered and provide good air flow. Regular plant inspections and good overall hygiene are very important in controlling mold.

Manual- Removing infected leaves and discarding, take care to disturb the leaf as little as possible to avoid spreading mold spores. Remove the top layer of soil and replace with sterile compost.

Organic- Copper and water spray.

Biological- Mycostop® is developed from a naturally occuring bacteria and can be used for the treatment of gray mold. It is available to the home gardener.

Chemical - A number of chemical controls are available but in limited availability to the home gardener. Plant damage can easily occurs as not all chemicals are safe for all plants, be sure to consult a pro at your local garden center.

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