Fusarium wilt is one of the most discouraging problems in the vegetable garden because it strikes healthy-looking plants during or just before fruit set, and there is nothing you can do to save them. The disease lives in the soil. It can survive there for decades. Once it is present in a bed, it changes how you manage that bed permanently.
Per UC IPM, fusarium wilt of tomato is caused by Fusarium oxysporum f. sp. lycopersici — a soil-borne fungus that specifically infects tomatoes and certain related crops. It does not infect humans or most other plants in the garden.
The disease is widespread in warm-summer regions including Long Island and the rest of the Northeast. Per Rutgers NJAES, fusarium wilt is one of the most common tomato diseases in New Jersey gardens, and the pattern is consistent across zone 7a: healthy transplants, vigorous early growth, then sudden one-sided wilting during the warmest weeks of summer.
What fusarium wilt is
Fusarium oxysporum f. sp. lycopersici is a soil-borne fungal pathogen that enters the plant through roots, colonizes the vascular system (xylem), and blocks water transport. Per Missouri Botanical Garden, "the fungus lives in soil and moves into plants through the roots," where it "produces spores in the water-conducting tissues, blocking water flow and causing the characteristic wilting."
The pathogen is favored by warm soil temperatures — per UC IPM, symptoms are most severe when soil temperatures are between 80°F and 90°F (27°C and 32°C). This is why fusarium wilt on Long Island typically appears in July, when soil temperatures peak.
There are three races of Fusarium oxysporum f. sp. lycopersici affecting tomato. Per NC State Extension, Race 1 is historically most common; Race 2 was identified later and overcome some early resistance; Race 3 is a more recent emergence. Variety labels use "F" for Race 1 resistance, "FF" for Races 1 and 2, and "FFF" for all three races.
More like this, monthly
Get the seasonal care notes — no upsell, unsubscribe any time.
One email per month from Thomas: what to plant, what to prune, what's about to break. Cited the same way as the guides.
Free. No spam. Same author as the guide you just read.
