How to Kill Fungus on Tomatoes
- 1). Spray horticultural oil onto the tomato plant. Be sure to spray underneath leaves and fruit. You can find horticultural oil at lawn and garden supply stores or home improvement stores. Horticultural oil is a mixture of naturally-occurring oils that do not harm your plants, but smother insects and fungal infections.
- 2). Stake your tomato plants to improve airflow and if your tomato plants are potted, move them to a sunnier location. Tie the plant to the stake loosely with garden twine. Air circulation and improved sunlight each work with the horticultural oil to kill off the fungus.
- 3). Check your tomato plant daily to be sure the fungus is dying. If the plant is not improving, reapply the horticultural oil seven to 10 days after the first application.
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