Tomato Pith Necrosis (Pseudomonas) on Tomatoes? How to Control It with Copper Fungicide

Caused by a bacterium in the soil called pseudomonas, it attacks only tomatoes and is expressed as brown /black lesions on infected stems and petioles.

When stems are cut, the center of the stem (pith) may be extensively discolored, hollow, or degraded, causing wilt.

It mainly attacks plants that are growing vigorously because of excessive levels of nitrogen.

Cloudy, cool weather and high tunnels provide ideal conditions for this bacterium.

Adventitious roots are plant roots that form from any nonrooted tissue and are produced both during normal development, and in response to stress conditions, such as flooding, nutrient deprivation, and wounding.

Another characteristic of the disease is adventitious roots, that come out of the clogged main stem and indicate that the plant is suffering and trying to get water from another source.

Copper fungicides are not able to provide control because this soil-borne bacterial pathogen is inside the plant.

However, they can minimize the spread of the bacterium from plant to plant.

Isolation of contaminated plants is required.

The bacteria are progressing between plants especially via pruning scissors.