How to Kill Fungal Spores in a Tomato Plot

Start fighting spore growth by removing fungus food. Remove all decaying plant matter from the plot and cultivate deeply as soon as you can work the soil to aerate it.

Choose disease-resistant plants with "VF" on their tags indicating Verticillium and Fusarium resistance. VF-resistant plants are not immune, and they are still susceptible to blights and leaf spot.

Treat plants with a foliar fungicide labeled for tomatoes early and at two-week intervals or according to directions on the bottle throughout the growing season to fend off early (Alternaria solani) blight. Begin spraying midseason to protect against late (Phytophthora infestans) blight. Blights arrive when local weather conditions favor development. To decide whether to begin spraying, consult your local agricultural extension’s news service or call its office to ask about blight presence in your area. Fungal spray contents vary from state to state, depending on local laws.

Remove Verticillium and Fusarium fungus hosts by rotating tomatoes and other Solanaceae family members -- potatoes (Solanum tuberosum), eggplants (Solanum melongena) and peppers (Capsicum spp.) -- with resistant plants such as carrots (Daucus carota), beans (Phaseolus spp.) or sweet potatoes (Ipomoea batatas). The University of California recommends keeping areas Solaceae-free for five to seven years to starve soil-borne wilts.

Maintain microbe-rich soil to gobble soil-born fungus spores. Dig in 2 inches or more of well-rotted compost each year to keep levels of fungus-eating microbes high and improve soil fertility and tilth.

Increase space between plants beyond the distance recommended on plant tags to increase air circulation and isolate infected plants.

Pull infected plants and those around them, including their root systems, to stop the spread of fungi such as Septoria leaf spot and wilts. Do not replant Solaceae family crops in the infected area.