First Report of Bacterial Leaf Scorch of Blueberry in Kentucky

Bacterial leaf scorch on blueberry was reported for the first time in Kentucky in October 2015. This disease is common within the southeastern states, including Georgia, Alabama, and Mississippi. While little is known about the disease, insect management is critical for preventing spread. Once infected, plants often die within one to two growing seasons. There is no cure for bacterial leaf scorch.

Bacterial Leaf Scorch of Blueberry Facts

  • Infected plants exhibit browning at the margins of leaves, and often a dark band develops between diseased and healthy tissue (Figure 1).
  • Defoliation occurs and stems/twigs may appear yellow in color (Figure 2).
  • Symptoms of bacterial leaf scorch can resemble abiotic/stress, so confirmation by a diagnostic lab is advised.
  • Caused by the bacterium Xylella fastidiosa subsp multiplex. The same subspecies is also known to infect oak and other common landscape trees (Figure 3).
  • Transmitted by leafhopper and treehopper insects.
  • Highbush blueberry varieties are susceptible to bacterial leaf scorch.
Figure 1: Marginal leaf scorch/burn on blueberry leaves infected with bacterial leaf scorch. (Photo: P. M. Brannen, et. al., Bacterial Leaf Scorch of Blueberry, University of Georgia)

Figure 1: Marginal leaf scorch/burn on blueberry leaves infected with bacterial leaf scorch. (Photo: P. M. Brannen et. al., Bacterial Leaf Scorch of Blueberry, University of Georgia)

Figure 2: Leaves drop from the plant and stems/twigs exhibit a yellow color. (Photo: P. M. Brannen, et. al., Bacterial Leaf Scorch of Blueberry, University of Georgia)

Figure 2: Leaves drop from the plant and stems/twigs exhibit a yellow color. (Photo: P. M. Brannen et. al., Bacterial Leaf Scorch of Blueberry, University of Georgia)

Figure 3: There are several subspecies of Xylella fastidiosa, all known to infect economically important crops. (Photo: European Food Safety Authority, 2013. Statement of EFSA on host plants, entry and spread pathways and risk reduction options for Xylella fastidiosa Wells et al., EFSA Journal, page 5, table 1)

Figure 3: There are several subspecies of Xylella fastidiosa, all known to infect economically important crops. (Photo: European Food Safety Authority, 2013. Statement of EFSA on host plants, entry and spread pathways and risk reduction options for Xylella fastidiosa, Wells et al., EFSA Journal, page 5, table 1)

Management Options

There is no cure for bacterial leaf scorch, and blueberry plants will eventually die once infected. The following suggestions may help reduce the spread of the disease:

  • Remove and burn, bury, or dispose of infected plants immediately
  • Avoid propagating potentially infected blueberry plants
  • Reduce plant stress and maintain plant vigor
  • Manage insect vectors

 

 

 

 

 

 

 

 

 

Additional Information

 

By Kimberly Leonberger, Extension Associate, and Nicole Ward Gauthier, Extension Plant Pathologist

 

 

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