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

11 Dec 2024
867

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

Controlled atmosphere: studies from Chile advance in collaboration with the Maersk Group

Post-harvest​

21 Feb 2024

The Centre for Post Harvest Studies (CEPOC) is conducting new studies on the use of controlled atmosphere in cherries. The effect of CA will be evaluated on the Regina variety harvested at three different ripening stages, simulating shelf life and marketing period.

RipeLocker supports post-harvest improvements with low-pressure chambers

Post-harvest​

11 Oct 2024

The group, which offers low-pressure chambers designed to extend freshness, stated that after six years of testing, it has overcome the challenges associated with cherry preservation, optimizing harvest timing and storage techniques.

In evidenza

Plastic covers for cherries: climate and irrigation benefits in Chile's Maule region

Covers

04 Jun 2025

A study in Chile’s Maule region analyzes the impact of plastic covers on cherry trees: temperature, humidity, solar radiation and water use. The data help growers reduce abiotic stress and improve post-harvest management during warm and dry seasonal conditions.

New Hungarian Mahaleb rootstocks for sweet cherry: performance and yield data

Rootstocks

04 Jun 2025

Explore the agronomic impact of new Hungarian-bred Mahaleb rootstocks for sweet cherry. Trial results on tree vigour, fruit weight, and yield in irrigated and rain-fed conditions. Complete and reliable data from test orchards near Budapest and Győr, Hungary.

Tag Popolari