How to Manage Pests

UC Pest Management Guidelines

SYMPTOMS

Tomato pith necrosis affects mature tomato plants. Symptoms include a brown discoloration and/or necrosis of the pith, which eventually leads to hollow chambers in the stem. The pith browning usually extends far up the plant. Profuse adventitious roots are associated with the stem where the pith is affected. Gray or dark brown lesions may appear on the surface of the stem. Affected plants may turn chlorotic and wilt.

COMMENTS ON THE DISEASE

Pith necrosis occurs when the first fruit set is close to mature green. High humidity favors its development. The bacterium may be seedborne. In California it is seen primarily in greenhouses, but can occur in fresh market tomato fields in the southern part of the state, and occasionally, but rarely, in Central Valley tomatoes.

MANAGEMENT

Management for tomato pith necrosis is not practiced in California.

PUBLICATION

UC IPM Pest Management Guidelines: Tomato
UC ANR Publication 3470
Diseases
R. M. Davis, Plant Pathology, UC Davis
G. Miyao, UC Cooperative Extension, Solano/Yolo counties
K. Subbarao, USDA Agricultural Research Station, Salinas
J. J. Stapleton, UC IPM Program, Kearney Agricultural Center, Parlier
Acknowledgments for contributions to the disease section:
B. W. Falk, Plant Pathology, UC Davis