Cause The soilborne fungi, Pseudopyrenochaeta lycopersici and P. terrestris, that survive in infected tomato root debris as well as durable microsclerotia that can persist in soil for years. These fungi may also infect eggplant and pepper while melon, squash, spinach, and safflower may also be hosts. Temperatures between 59°F and 68°F are optimum for disease development. The fungi are slow growing and difficult to isolate from infected plant roots.
Symptoms Infected plants develop interveinal chlorosis on leaves and premature defoliation. Plants appear unhealthy and wilting may occur. Root volume is reduced. Small roots rot away while brown lesions appear on small roots and larger roots develop "corky" lesions.
Cultural control
- Plant in pathogen-free fields, or use a 4-year field rotation.
- Delay planting until temperatures are warmer.
- Hill up plants to promote adventitious root growth.
Biological control
- Stargus at 2 to 4 quarts/A plus a nonionic surfactant on 7- to 10-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.
Koike, S.T., Gladders, P., and Paulus A.O. 2007. Vegetable Diseases: A Color Handbook. St. Paul. MN: APS Press.
Testen, A.L., Shaw, R.S., Rotondo, F., Moodispaw, M.R., and Miller, S.A. 2023. A quantitative PCR method to detect the tomato corky root rot pathogens, Pseudopyrenochaeta lycopersici and P. terrestris. Plant Dis. 107(9):2673-2678. https://doi.org/10.1094/PDIS-08-22-2009-RE.