How to Recognize, Manage and Prevent Gray Mold Fungus on Strawberries, Tomatoes and Other Plants

The gray mold fungus, shown here, is probably the most common form of damage (rot) to strawberries, but it can also attack a few hundred other plants as well.
The gray mold fungus, shown here, is probably the most common form of damage (rot) to strawberries, but it can also attack a few hundred other plants as well.

Gray Mold Fungus - Recognizing It

Gray mold fungus on strawberries is UGLY! You can spot it when lesions start appearing on leaves, the blossoms, stems or the fruit of the strawberry. The lesions are water-soaked and in advanced stages, covered with gray spore masses. The fungus causes the strawberry to soften and soon rot, and all of your hard work at cultivating delicious and beautiful strawberries has all been for nothing. Don't let that happen to you; learn to prevent the mold, or at the very least learn to recognize it in its early stages so that your crop is not ruined.

The gray mold fungus will usually appear on fruit as soft, light brown areas which enlarge quickly and the infected fruits remaining on the plant usually dry up and are covered with gray, dusty spores. When air movement is poor and the humidity is high, conditions are just right for the infection to become severe; well-protected areas of the plants are the most susceptible to this unwanted, nasty houseguest.

Preventing Gray Mold Fungus

When plants are properly spaced, it reduces the chance of fungus showing up on your plants because they have adequate air circulation. If you are really smart and can determine the prevailing winds, orient the strawberries in the same direction as the winds. Irrigating on the ground (rather than overhead) helps as well, and keep your fruit off the ground by mulching with straw or pine needles. Plastic sheeting works as well. And, remember to harvest your strawberries every few days when they are ripe. Don't give them the opportunity to develop this awful fungus. Also something to remember: the gray mold fungus becomes more severe when crops are not rotated.

Gray Mold Fungus Attacks Tomatoes as Well

Gray mold fungus can also attack your crop of tomatoes.  The symptoms may resemble frost damage, but it is distinguishable by the gray mold covering the affected areas in moist conditions.
Gray mold fungus can also attack your crop of tomatoes. The symptoms may resemble frost damage, but it is distinguishable by the gray mold covering the affected areas in moist conditions.
It is important to remove the affected strawberries in hopes that the others are not ruined as well.
It is important to remove the affected strawberries in hopes that the others are not ruined as well.

Once Affected, Proper Management Is the Key

The best way to manage gray mold fungus is by removing all infected plant parts immediately.The spores survive in plant debris and from spring to early fall, they are spread through the air. Get rid of them before more plants are affected. The only chemical control that I am aware of for strawberries is a fungicide that contains captan. Unfortunately, for tomatoes, you are out of luck when it comes to chemical control, unless something has been marketed in recent years that I am unaware of. If gray mold attacks your flowers (annuals and perennials), you will need to spray with a fungicide containing chlorothalonil. Always read the label for each fungicide you buy and only apply them according to direction. Sometimes they are simply a necessary evil.

This is a great fungicide for strawberries, and it is sold everywhere.  Online, you can buy it at Amazon.com.
This is a great fungicide for strawberries, and it is sold everywhere. Online, you can buy it at Amazon.com.

Great Video If You Are Into Organic Gardening

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Comments 3 comments

therenegadehippie profile image

therenegadehippie 17 months ago from Southern California

Unfortunately I transplanted my strawberries this year and started having problems with this fungus on two plants. I have been looking everywhere on what to do. Thank you for sharing.


Randy M. profile image

Randy M. 4 years ago from Liberia, Costa Rica

Solid advice on cultural control methods of this disease.


greg maxwell 4 years ago

Great Article

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