Healthy tomatoes are big, beautiful plants that produce a large volume of delicious fruit during summer growing seasons. Tomato plants are one of the more popular vegetable plants for home gardens because they are relatively easy to grow. In spite of that fact, they can develop aggravating diseases like white mold. White mold, like most tomato plant diseases, is easy to avoid with proper care and maintenance.
Temperature and Humidity
Mold and fungus occur at a higher rate in greenhouse environments due to the high humidity and heat. Indoor climates require good ventilation and careful regulation to avoid white fungi. Outdoor plants need protection from extremes in heat and humidity as well. Tomatoes love sun and heat but are vulnerable to disease in extreme temperatures over 90 degrees F. Pay careful attention to watering schedules. Watering late in the day when the plants do not have time to dry off before nightfall encourages mold and fungus.
Plants in greenhouses and outdoor garden plots need room for airflow. Do not crowd plants. Lack of circulation encourages high humidity inside the plant rows and increases the chance for fungus buildup. Allow at least 2 feet between each seedling when first planting in the spring so that adult plants still have airflow between them.
Rotation and Support
A key to fighting all types of tomato plant disease including white fungus is crop rotation. Never place tomato plants in the same location more than once per three-year span; four years is even better. Leave a wide berth between successive plots as well to avoid encroachment of disease into new area. Keep plants off the ground with sturdy cages. Leaves and fruit on the ground trap moisture, humidity, and have restricted airflow--all of the environmental situations in which fungi thrive.
Wrap the bottom of the tomato plant stem with aluminum foil at planting time. This prevents Southern Blight, a form of white fungi, that may still exist in the ground from creeping up the stalk to the leaves, blossoms and fruit.
Fungus overwinters on plant stems and debris. Clean garden area thoroughly and burn all plant materials, or bury it deep far from the plot.
Keep on top of weed growth. Apply a heavy layer of mulch around tomato plants to discourage weed growth. Mulch keeps the lower leaves of the plant off the ground as well. Weeds not only choke out plants and deprive them of vital nutrients in the ground; they give fungi the perfect environment to live in.