Tomato Leaf Mold


Leaf mold is a common fungal disease that affects tomatoes that are cultivated in especially humid environments. Feeding off of the humidity, the mold grows and thrives after attaching itself to the leaves of the tomato plant. Once the mold is noticed, immediate action is required to save the plant, otherwise the foliage will be compromised, which will reduce the amount of tomatoes your plants will yield. Fortunately for tomato growers, this fungal disease is relatively easy to treat and cure.


The first signs of leaf mold are, as you might expect, on the leaves themselves, as the topside of the leaves start to develop small gray, yellow, white, or pale green patches. The underside of the leaves begin to develop a fuzzy texture and turn purple. Oftentimes, the fuzz will appear in an olive green color. The fuzzy texture is actually the spores of the mold fungus. The fruit of the tomato plant is rarely infected by leaf mold.

As the disease progresses, the infected tissue of the leaves become yellowish-brown and the leaf starts to wither, eventually falling off of the plant altogether. If not treated, the plant will eventually wither and die.

Though the fruit and blossoms of the tomato plant are rarely affected by leaf mold, it does occur occasionally. When the fruit or flower is infected, it appears as a black legion on the surface of the fruit or bloom. The black part grows and spreads out, eventually covering over half of the surface area of the flowerhead or fruit. Tomato leaf mold can affect both ripe tomatoes and immature green tomatoes.

Management

Upon noticing the infected areas, the first step is to let the plants air out and dry. If they are being cultivated in a greenhouse, expose them to dry air conditions, because the humidity that the fungus needs to survive and thrive is dried up in the open air.

If the tomatoes are being cultivated outdoors, try to keep the leaves dry when watering the plants. One thing you can do to help keep the leaves as dry as possible is to water in the early morning hours, that way the plant has plenty of time to dry before the sun comes out, which will keep the humidity around the leaves low. You can also try drip irrigation methods, or soak watering methods to attempt to water the soil without ever wetting the leaves of the plant.

Another treatment option is fungicidal sprays. When using fungicide sprays, be sure to thoroughly cover all parts of the plant that is above ground, focusing specifically on the underside of leaves. Calcium chloride sprays are among the most highly recommended types for leaf mold. There are a few organic fungicides on the market as well.



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