Overhead irrigation, dew, and rain all contribute to its spread.īe sure to always water plants at the soil line to avoid sprinkling the leaves, or use drip irrigation or a soaker hose. The disease is spread by airborne spores, or when infected soil touches the plants. The fungus produces a toxin that causes the tissue between the leaf veins to die and turn dark brown or black.Īnother symptom is concentric rings on green fruit – either when they are still on the plant, or after an early harvest.

The main symptoms are cankers – dark brown recessed lesions – on the stems near the soil line, often with concentric rings.

Photo by Bruce Watt, University of Maine,, via CC BY-SA. lycopersici, this fungus is closely related to the one that causes early blight, but in addition to attacking the leaves and fruit, it also commonly causes disease on the stems. Alternaria Stem CankerĬaused by Alternaria alternata f. No part of the plant is safe – the roots, stems, leaves, flowers, or fruit, both green and ripe, can all be infected by a number of different types of fungi. Caused by Fungal PathogensĪs is the case with many plants, a wide array of fungi may attack tomato plants. We offer suggested treatments, as well as steps you can take to prevent the same issues in subsequent growing seasons. Others may be fatal, but removing diseased plants from the garden is an important step, to avoid further spread throughout the garden. If you discover a problem, all is not lost! You may still be able to bring in a delicious harvest.īy checking your plants regularly and taking action at the first sign of a problem, many of the diseases and other issues discussed here are treatable, if not curable. Common Tomato Diseases and Physiological Disorders

Tomato early blight disease