Discovery and evaluation of bacteriophage for management of fire blight of apple and bacterial canker of sweet cherry
MSU researchers George Sundin and Nikki Rothwell explored two issues affecting apples and cherries.
Researcher: George Sundin
George Sundin, a University Distinguished Professor in the MSU Department of Plant, Soil and Microbial Sciences, and Nikki Rothwell, the coordinator of the Northwest Michigan Horticulture Research Center, explored two issues affecting apples and cherries.
Fire blight, caused by the bacterial pathogen Erwinia amylovora, is a devastating disease and a limiting factor to apple and pear production in Michigan and throughout the world. The significance of fire blight includes both current season yield loss due to flower infections and systemic infections leading to rootstock blight and tree death. Young orchards of susceptible apple cultivars are particularly vulnerable to tree losses due to fire blight.
A disease epidemic in 2000 in southwest Michigan resulted in the death of over 400,000 trees and eliminated 20% of the acreage in this region alone, a $50 million economic loss. This research addressed the Michigan Apple Committee research priorities to improve quality and consistency including fire blight disease control. Disease is a major impediment to fruit quality and to tree health. This research will lead to improved strategies for fire blight management in high-density plantings.
Bacterial canker, caused by the pathogen Pseudomonas syringae pv. syringae (PSS), is a significant problem on sweet cherry that can cause symptoms such as blossom blast, which kills flowers, and cankers on limbs that can ultimately kill trees. Bacterial canker is exacerbated by prolonged wet, cold springs, a common occurrence during bloom in Michigan. Bacterial canker is a limiting disease in that it has the potential to reduce the expansion of the Michigan sweet cherry industry, particularly for growers planning to move toward the advanced high density systems where extensive pruning is required.
The team showed that the phage preparations tested provide control that is equivalent to that obtained with commercially available biocontrols for fire blight. They expect that their work to develop new phage treatments for bacterial canker will lead to viable solutions for Michigan tree fruit growers in the near future.