By Scout Nelson
The University of Minnesota (UMN) Extension identifies bacterial canker as a serious disease affecting tomato plants. The disease is suspected to be seedborne and can survive in infected plant debris, weeds, and soil for long periods, making prevention an important management strategy.
Bacterial canker is caused by the pathogen Clavibacter michiganensis subsp. michiganensis. Warm temperatures, high humidity, and excess moisture create favorable conditions for infection and disease spread.
Symptoms can appear at different growth stages and may vary depending on conditions. Seedlings may develop white raised spots, leaf discoloration, wilting, and, in severe cases, plant death.
As the disease progresses, leaves may develop yellow-to-tan areas between veins, brown margins, and wilting that often begins on one side of the plant. Severe infections can cause the entire plant to collapse.
Stem symptoms include internal brown discoloration, vascular streaking, stem splitting, and the development of long brown cankers. Infected fruit may develop raised white spots with brown centers, commonly known as “bird's-eye spots,” which reduce market quality.
The disease spreads through infected seed, transplants, contaminated tools, and routine activities such as pruning and staking. It can spread rapidly in greenhouses and high tunnels and survive for years in undecomposed tomato debris.
UMN Extension recommends crop rotation and avoiding tomatoes, peppers, potatoes, and eggplants in the same location for three to four years. Using disease-free seed and transplants, keeping foliage dry, providing good airflow, sanitizing equipment, and removing infected plant material can help reduce the risk of bacterial canker.
Photo Credit: gettyimages-bastetamn
Categories: Minnesota, Crops, General