Frequently Asked Question

Symptom: leaves turning yellow, brown, wilting -- usually starts small and spreads to other parts of the plant.

What is happening: the plant has a disease that is spreading

Details: there are several common diseases that could cause this. It may be start with fungal spores in the soil that have splashed up to the bottom leaves with rain. It may be something that was transferred to the plant from an infected pruning tool or an insect. Humid environments are perfect for fungal diseases to spread. Rapid changes in temperature cause stress in the plant and make it more susceptible to disease. More information about each of the common diseases will be listed below, but prevention and treatment is similar for all of them.

What can be done: Noticing the problem early is very important. Prune the diseased portions of the plant and remove the material from your garden area. (don't add it to your compost) Be sure to clean your pruning tool before and after each cut you make. (bleach solution, alcohol wipe, or lysol spray) Often, the affected parts of the plant are on the lower areas, so the plant will keep growing and the continue to develop fruit. If the disease has spread to most of your plant, there isn't much that can be done.

Prevention: Avoiding the conditions that allow these diseases are the most important things to do.

• Airflow: locate plants in a way that allows airflow around them. Don't crowd the plants. Keep the plant trimmed so air can circulate through the plant's inner parts.
• Trim lower branches: don't allow any leaf surface near the ground. Prune leaves and branches on the lower 12" of the plant so that soil can't splash up on the leaf surfaces.
• Mulch: keep a layer of organic material on top of the soil's surface to absorb and cushion rain and water droplets
• Choose disease resistant varieties: Tomato varieties that are bred to be resistant to diseases will have extra letters in their name
  • V Verticillium Wilt
  • F Fusarium Wilt
  • FF Fusarium, races 1 and 2
  • FFF Fusarium, races 1, 2, and 3
  • N Nematodes
  • A Alternaria
  • T Tobacco Mosaic Virus
  • St Stemphylium (Gray Leaf Spot)
  • TSWV Tomato Spotted Wilt Virus,
• Keep it clean: Pick up fallen leaves and fruit. Keep area weed-free.
• Rotate crops: Don't plant tomatoes, eggplant, or potatoes in the same space that tomatoes, eggplant, or potatoes were planted last year.
• Raised Beds (or straw bales): Planting in well drained soil (or non-soil!) helps the situation by quickly moving excess moisture away from the plant.
• Don't handle or move wet plants: this increases the chances of spreading any disease that may be present

Common diseases and links to more information on each one

• Early Blight - https://extension.umn.edu/diseases/early-blight-tomato
• Late Blight - https://www.gardeners.com/how-to/prevent-late-blight/7262.html
• Septoria Leaf Spot - http://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/diseases/fungal-spots/septoria-leaf-spot-of-tomato.aspx
• Fusarium Wilt - https://extension.umd.edu/hgic/topics/fusarium-wilt-tomato-vegetables
• Verticillium Wilt - http://vegetablemdonline.ppath.cornell.edu/factsheets/Tomato_Verticillium.htm