Plant Problem Diagnosis Key / Diseases
Fusarium wilt
Fusarium oxysporum (crop-specific forms)
A soil fungus that enters roots and plugs the water-conducting tissue. Each crop has its own form, it is favored by warm soil, and it survives in soil for many years.
Signs
- Yellowing and wilting on one side of the plant or one side of a leaf, lower leaves first.
- Brown streaks in the water tissue just under the skin of the lower stem.
- Plants wilt in the heat, partly recover at night, then decline.
What favors it
Warm soil (above about 80 °F / 27 °C), acidic or sandy soil, ammonium fertilizer, root-knot nematodes, and repeated plantings of the same crop.
Prevention
- Grow resistant varieties (marked F on packets; check which of races 1-3 they resist).
- Rotate out of the crop's family; the fungus lasts years, so rotation slows it rather than ending it.
- Raise soil pH toward 6.5-7.0 and feed with nitrate rather than ammonium nitrogen.
Often confused with
Sources
- Fusarium wiltUniversity of Minnesota Extension
- Fusarium Wilt of TomatoNC State Extension
- Fusarium Wilt of TomatoConnecticut Agricultural Experiment Station
Treatment by crop
Cultural, biological and chemical options in the order to use them, and notes written for each crop.
Identification is free. Treatment is on the Home and Pro plans.
Questions in the key that lead here
- Look the plant over, leaf undersides included. Are insects, mites, slugs, eggs, webbing or droppings on it?
No, only damage or discoloration - Where is the problem?
The whole plant or whole stems - How is the soil or media?
Moist or wet - Lift the plant or pull back the media at the stem. What do the roots look like?
White or cream, firm - Which plant is wilting?
Another plant - Slice the lower stem lengthwise. Is the tissue just under the skin streaked brown?
Yes, brown streaks - How did the wilt show up?
One side of the plant, or one side of a leaf first
Not a match? Start the key or describe what you see.
More photos
More from university Extension: search Extension pages on fusarium wilt, or find a plant diagnostic lab through your state's Extension.
Other diseases
- Anthracnose
- Apple scab
- Bacterial leaf scorch
- Bacterial leaf spot
- Bacterial wetwood (slime flux)
- Bacterial wilt of cucurbits
- Black knot
- Black spot of rose
- Bleeding canker
- Boxwood blight
- Canker diseases
- Cedar-apple and related rusts
- Crown gall
- Damping-off
- Downy mildew
- Dutch elm disease
- Early blight and Alternaria leaf spot
- Elm yellows (phloem necrosis)
- Fire blight
- Gray mold (Botrytis)
- Late blight
- Mosaic viruses
- Needle cast and tip blight
- Oak wilt
- Powdery mildew
- Root and butt rot
- Root rot (Pythium and Phytophthora)
- Rust
- Septoria leaf spot
- Shade tree anthracnose
- Sooty mold
- Tar spot of maple
- Tomato spotted wilt and impatiens necrotic spot viruses
- Verticillium wilt
- White mold (Sclerotinia)
- White pine blister rust