If you grow tomatoes or peppers, you may have watched fusarium wilt take down your plants. It’s not much fun. One by one, branches yellow and die, until the entire plant is wilted and yellow. Fusarium wilt, like the related verticillium wilt, is caused by fungi, which enter the plant through its roots and block the movement of water and nutrients to the leaves. Both wilts are soilborne diseases.
Once a plant is invaded by the fungi that cause fusarium wilt, the plant’s leaves begin to wilt. For a time, they may recover at night. Wilting can begin either at the top of the plant or in the lower leaves, and it then spreads throughout the plant. Fusarium wilt can kill a plant quickly, or it may take a few months. Infected tomato plants may still produce fruit, though not as much and not of good quality, but pepper plants generally collapse quickly. Potatoes and eggplants, being relatives in the Solanaceae family, are also vulnerable to fusarium wilt.
Because the fungi that cause fusarium wilt are embedded in the plant’s tissues, there’s not much you can do once the disease sets in. The best way to battle fusarium wilt is to prevent it by rotating crops each year and by planting disease-resistant cultivars. Tomatoes bred for resistance to fusarium wilt are labeled “F” and those resistant to verticillium wilt are labeled “V.” Be aware that heirloom tomato varieties don’t carry resistant genes. After you’ve grown tomatoes in one spot, don’t plant tomatoes, potatoes, peppers, or eggplants there again for four to six years. Remove and destroy infected plant material as soon as possible. Clean tools with a solution of one part bleach to nine parts water. If your whole yard is infected and you’re desperate for a home-grown tomato, try planting in pots.
—Photo courtesy of the Kemper Center for Home Gardening at the Missouri Botanical Garden.