Bacterial canker: symptoms, causes, and prevention in the sweet cherry tree during the fall season

11 Dec 2024
930

The bacterial canker of sweet cherries is caused by the bacterium Pseudomonas syringae pv. syringae (PSS) van Hall (Romoli, 1963, Latorre et al., 1980). This pathogen is commonly associated with humid and cold climates (Latorre, 2008). The pathogen P. syringae can colonize any plant tissue without causing infections or symptoms. However, the bacterium requires a wound or natural opening, along with conditions of moisture or standing water, to infect trees. As a result, autumn becomes a critical period for preventive management.

Figure 1.

Symptoms in Sweet Cherry

The most evident symptoms of bacterial canker in sweet cherry are a dark canker, often accompanied by gummosis (reddish-brown exudate) (Latorre, 2008, CABI, 2020) (Figure 1). Symptoms commonly develop at the base of trees, particularly in younger trees, which are more susceptible to damage caused by machinery, rodents, frost, and irrigation. These factors provide ample opportunities for PSS infection.

Figure 2: Gummosis due to bacterial infection in sweet cherry (left) (photo: C. Serban), dormant wood with bacterial infection in spurs (right) (photo: B. Sallato).

Management Recommendations

  • Early defoliation: Leaf fall creates a natural wound that can become an infection site for the pathogen. Early defoliation, when conditions are dry and warm, reduces the risk of infection (see Early Autumn Defoliation for Sweet Cherry).
  • Prevent damage: Avoid damaging trees in moist conditions, especially during activities like weeding, pruning, or any mechanical wounding, as this increases the risk of infection.
  • Weed management: Since weeds can host PSS, adequate weed management will reduce the risk of disease transmission.
  • Pruning: Prune and remove infected tissues during dry weather, cutting below the visible canker. To prevent transmission through pruning tools, consider removing cankers before routine pruning.
  • Severely infected trees: Remove severely infected trees to reduce the spread of the disease.
  • Frost protection: Pseudomonas syringae is an ice-nucleating bacterium and can freeze cellular water at higher temperatures. Protecting trees from frost reduces the risk of damage.
  • Copper resistance: In many regions of the United States and the world, copper-resistant strains of the bacterium render copper-based sprays ineffective.

Source: WSU
Images: WSU; Plantsdb


Cherry Times - All Rights Reserved

What to read next

Sweet cherry: fruit quality begins with pollination

Tech management

09 Aug 2024

Data from one study show that the fruit set percentage of the artificially pollinated flowers was only 1.1 per cent, compared to 15.4 per cent for the freely pollinated flowers. Furthermore, cherries from the freely pollinated flowers showed superior quality attributes.

INSTINCT project: efficient and sustainable agriculture thanks to artificial intelligence

Crop protection

03 Jul 2024

The Laimburg research institute has launched the INSTINCT project, a pioneering initiative in the field of precision agriculture. INSTINCT focuses on the use of advanced technologies to optimise crop management and improve agricultural practices.

In evidenza

Brassinolide protects “Tieton” cherries from cold damage during storage in China

Post-harvest​

26 Jun 2025

A study from Yantai, China shows that brassinolide application improves the storage of “Tieton” cherries, significantly reducing cold damage, weight loss, and degradation of visual and nutritional quality of the fruits during prolonged cold storage conditions.

Meda cherries tested in 12 European countries, first fruits harvested in the Netherlands

Varieties

26 Jun 2025

Meda cherries gain traction across Europe: trials in 12 countries, first harvest in the Netherlands, and over 1,200 hectares assigned worldwide. The project spans USA, Chile, South Africa and China, focusing on quality, earliness, innovation and agronomic sustainability.

Tag Popolari