Controlling tomato fungus is a common challenge that tomato growers must face. If a tomato plant becomes infected with tomato fungus, it may be overrun very quickly. If infected with a fungus, a tomato plant may show several symptoms: The leaves may shrivel up and crumble, or turn yellow, or even become covered in black spots and fuzzy white mold.
Fungal diseases can kill the plant and quickly spread to other tomato plants. If a fungus problem is affecting your tomato plants it is important to take action quickly to bring it under control. If not, there are still many steps that you can take to prevent tomato fungus diseases from occurring.
This article lists many different tomato fungus varieties, with pictures of each one to help you to identify them. It also contains many tips for preventing fungus diseases on tomatoes, as well as advice on using fungicides to control a tomato fungus problem.
Control tomato fungus – tomato fungus types
Tomato fungus problems can be caused by several fungal leaf or fruit diseases or blights. The most common is known as Septoria leaf spot.
Septoria Leaf Spot
Septoria leaf spot usually appears on tomato leaves after the first fruits set. The fungus typically affects the lower leaves first. Septoria can be identified by small grey spots with black centers. These spots are usually confined to the leaves, but can also appear on the vines. Septoria leaf spot on tomatoes can cause the affected leaves to turn yellow and eventually fall off. Leaf drop reduces the fruit production of the tomato plant.
An additional side effect on a tomato plant shedding its leaves is that the fruits have less shade from the sun, allowing sun-scald. Tomato Septoria enjoys cool, rainy or humid weather conditions.
A tomato leaf showing Septoria Leaf Spot - notice the green leaf beginning to yellow around the spots
Early Blight
Early blight on tomatoes is one of the most common tomato growing problems faced by vegetable gardeners. Early Blight causes a few large spots to appear on each affected leaf. The spots look like several rings inside each other – like the rings of a tree. Eventually the leaf will turn yellow and drop.
Like Septoria Leaf Spot, Early Blight begins on the lower leaves. Under cool, moist conditions it will spread upwards, causing many leaves to drop. Early Blight on tomatoes can also affect the fruit, creating large dark rings or spots. Tomatoes with early blight spots will drop before they are fully grown.
Early Blight problems are typically going to affect tomato plants early-on in the season. Other plants are susceptible to early blight, including aubergines and potatoes.
Notice the concentric rings, a sign of early blight on this tomato leaf
Powdery Mildew
This is another fungal tomato disease. Powdery Mildew is very easy to identify. It appears on the top of tomato leaves as white powdery spots. Sometime the spots will be yellowish, but still powdery. Powdery mildew is not usually a fatal disease to tomato plants, but it will weaken them and lower the quality of the fruit. Like all other tomato fungus problems, it thrives in damp, moist and humid conditions, crowded vegetable gardens and where the air circulation is restricted.
A severe mildew problem will make affected leaves leaves turn yellow and then brown and crusty. If the leaves drop, it may result in sun damage to the tomatoes and will result in a lower tomato yield.
Powdery mildew fungus thrives in conditions where the weather is humid during the night (higher then 85%) and then warm and dry during the day.
White powdery mildew tomato fungus problem
Blossom End Rot
A common fungus that affects the tomato fruit. Dark spots can appear at the blossom end of the tomato (the bottom). The spots enlarge while the tomato starts to rot. Blossom end rot is often worsened by a lack of calcium in the fertilizer.
The blossom end rot problem on this tomato is quite advanced
Anthracnose
Anthracnose is a fungus that affects the tomato fruit. The first sign of Anthracnose is a small dark pit appearing on the fruit, which becomes larger and darker and is often joined by further pits. This fungus is commonly picked up from the soil, either by splashing soil on the plant during watering, or from tomatoes that are resting on the ground. It affects both green and red fruit. Often several pits will merge into one large rotten area. The fungus spores can survive the winter cold.
Small pits in tomato caused by anthracnose fungus
Control tomato fungus – causes of fungus
Tomato fungus diseases are worsened by certain conditions. Fungus loves moisture and cool conditions, so the weather and environment are a big factor in the susceptibility of your garden to tomato fungus problems. Rain, dew and other sources of moisture – especially close to the ground – encourages fungus to grow.
Best of Luck this season and remember to keep an eye out! Mark
