Cause The fungus, Fusarium oxysporum f. sp. basilica, causes a wilt of basil in many regions of the world, including the Willamette Valley of Oregon. This soilborne fungus can persist for years in soil or plant debris. The disease is spread by air or soil and can be seedborne.
Symptoms Affected plants' leaves grow asymmetrically, are yellowish, malformed, and may curl. Plants wilt, starting from the abnormal leaves, leading to plant death. Young plants die rapidly, in 4 to 7 days after symptoms are first evident. There is vascular browning and it is more notable in the affected shoot area. A pinkish orange layer of mold may cover stems. Rot of the roots and crown has been observed in Israel but it is typical for roots to appear healthy when wilting is evident.
Cultural control
- Plant pathogen-free seed in pathogen-free soil or potting mix.
- The varieties, Aroma 2 and Nufar F1, have resistance to Fusarium wilt.
- Maintain good air circulation in row and plant spacing.
- Thoroughly clean and disinfect used pots or flats.
- Remove and destroy infected plants.
Chemical control
- Switch 62.5WG at 11 to14 oz/A applied prior to or at the onset of the disease. Do not apply more than two (2) sequential treatments before alternating to another mode of action. Preharvest interval is 7 days. 12-hr reentry.
Biological control Efficacy unknown in the Pacific Northwest.
- Actinovate AG at 3 to 12 oz/A as a soil drench at planting. 4-hr reentry. O
- Actinovate Lawn & Garden at 1/2 to 1 teaspoon/gal water. H O
- Prestop WG as a soil drench or incorporation into growing medium. 4-hr reentry. O
- Rootshield WP at 3 to 5 oz/100 gal water for greenhouse soil drench and field chemigation, or at 16 to 32 oz/A as an in-furrow spray. 4-hr reentry. O
References Garibaldi, A., Gullino, M.L., and Minuto, G. 1997. Diseases of basil and their management. Plant Disease 81:124-132.
Keinath, A.P. 1994. Pathogenicity and host range of Fusarium oxysporum from sweet basil and evaluation of disease control methods. Plant Disease 78:1211-115.
McReynolds, R.B., and Ocamb, C.M. 2006. Evaluation of materials for the control of Fusarium wilt in field-grown sweet basil, 2005. Fungicide and Nematicide Tests Report No. 61:V117.