See:
Tomato (Solanum lycopersicum) - Fusarium Foot Rot
Tomato (Solanum lycopersicum) - Fusarium Wilt
Tomato (Solanum lycopersicum) - Varietal Resistance
Tomato (Solanum lycopersicum) - Verticillium Wilt
Cause Fusarium F. oxysporum f. sp. radicis-lycopersici, a fungus that lives in soil and can cause rot of the below-ground portions and subsequently plant wilting. Disease is favored by cool, wet soils, a low soil pH, and ammonium nitrogen. F. oxysporum f. sp. radicis-lycopersici can survive several years in soil and can be spread by infested equipment, infected transplants, and windborne or waterborne infested soil. Tomato seed has been reported to be contaminated with this pathogen. Hardware and structure portions can be contaminated or infested by the fungus; this fungus has been recovered from plastic and wooden stakes as well as greenhouse walls and support poles. Shore flies (Scatella stagnalis) and fungus gnats (family Diptera) have been reported to transmit this fungus to healthy plants if diseased plants are nearby. Disease can spread within a planting by infected root contact between plants and through irrigation water.
Although this fungus causes disease specifically on tomato, it may colonize the roots of nonhosts in the absence of any symptoms, although sometimes infections will result in the development of symptoms. Plant families and species besides tomato that can be infected by this fungus include: Brassicaceae (Brassica juncea, B. oleracea), Cucurbitaceae (watermelon), Leguminosae (fava bean, snap or dry bean, pea, peanut, soybean, and clovers), and Umbelliferae (celery, carrot) as well as spinach, beet, onion, weed, and weedy plants such as plantain (Plantago lanceolate), carpetweed (Mullugo verticillata), Queen Anne's Lace (Daucus carota) Shepherd's purse (Capsella bursa-pastoris), and other weeds.
Symptoms Lower leaves yellow and plants wilt during the hot part of the day, especially during flowering, but may recover in the evening until disease becomes more advanced. Eventually the leaves remain wilted, shrivel, turn brown, and die; the entire plant can die. Rot symptoms on the tap root and the lower stem at the soil line are typical, sometimes a vascular discoloration may be found along the bottom 1-ft portion of the main stem. Can be confused with Fusarium wilt. Damping-off of young seedlings may be observed.
Cultural control
- Use pathogen-free seeds and transplants. Treat seeds with a hot water treatment (122°F for 25 minutes) or use a chemical seed treatment listed under chemical control below.
- Use resistant varieties or resistant rootstock if grafting.
- Remove and destroy all affected plant tissue, including roots.
- Thoroughly clean propagation equipment, especially if reusing plant trays and pots.
- Clean soil from equipment including machinery, footwear, gloves, etc., after working in an affected planting.
- Manage for shore flies and fungus gnats inside greenhouses, especially if propagating tomato.
- Incorporate plant debris after harvest.
- Rotating out of tomatoes 4 to 6 years may reduce losses.
Chemical control
- Seed treatment with sodium hypochlorite. Wrap seed in a cheesecloth bag and soak with agitation 40 minutes in 1.05% sodium hypochlorite (1 part household bleach to 5 parts water). Spread out seed and allow to dry. Prepare fresh solution for each batch of seed.
- Regalia Biofungicide (Group P5) at 1 to 4 quarts/A as an in-furrow treatment. Does not benefit from the addition of an adjuvant. 4-hr reentry. O
Biological control
Application of microbial antagonists can reduce the activity of this pathogen.
- Bexfond at 7 to 28 fl oz/A. 4-hr reentry. O
- Stargus at 6 to 8 fl oz per 1,000 ft row as an in-furrow treatment, or 3 to 4 quarts/A as a soil drench (drip or chemigation) on 10- to 21-day intervals. Preharvest interval is 0 days. 4-hr reentry. O
References Jones, J.B., Zitter, T.A., Momol, T.M., and Miller, S.A. 2014. Compendium of Tomato Diseases, 2nd Ed. St. Paul, MN: APS Press.
McGovern, R.J. 2015. Management of tomato diseases caused by Fusarium oxysporum. Crop Protection 73:78-92.