Grey Mold on Tomatoes: How to Treat Grey Mold on Tomato Plants
A disease of tomatoes that occurs in both greenhouses and gardens is called tomato gray mold. Gray mold on tomato plants is caused by a fungus with a host range greater than 200. Tomato gray mold also causes post-harvest rot at harvest and storage and can cause a variety of other diseases, including wetting and pests. Given the severity of the disease, what are the symptoms of tomato gray mold and how is it managed?
Symptoms of gray mold on tomato plants
Grey mold, or botrytis, does not only affect tomatoes, but also other vegetables:
- Beans
- Cabbage
- Endive
- Lettuce
- Watermelon
- Peas
- Peppers
- Potatoes
Caused by the fungus Botrytis cinerea , these unicellular spores are found on several branches, which gives the fungus its name from the Greek botrys, which means bunch of grapes.
Grey mold on tomatoes appears on seedlings and young plants and takes the form of a grayish-brown mold covering the stems or leaves. The flowers and the tip of the fruit are covered with dark grey spores. Infection spreads from the flowers or fruit to the stem. The infected stem turns white and develops a canker that can encircle it, which can lead to wilting of the infected area.
Tomatoes infected with gray mold turn light brown to gray when they come into contact with other infected parts of the plant or develop white rings called «ghost spots» if infected directly by airborne spores. Infected and stored fruits are covered with a grey layer of spores and may also have a white mycelium on the surface of the fruit.
Managing grey mold on tomatoes
Grey mold is more important in case of rain, heavy dew or fog before harvest. The fungus also infiltrates the plant tissues. The spores of this fungal disease reside in the residues of host plants such as tomatoes, peppers and weeds and are spread by wind. The spores attach to the plants and create an infection when water is available. The disease progresses most rapidly when temperatures are between 18 and 24°C.
To combat the incidence of gray mold, irrigation must be carefully managed. Tomatoes that are allowed to come in contact with water are more likely to become infected. Water at the base of plants and allow topsoil to dry out between irrigations.
Handle plants and fruit with care to avoid injury, which can open a portal to disease. Remove and destroy infected plants.
Fungicides can be used to prevent infection, but they do not suppress the disease in already infected plants.
