Reducing Losses by Reducing Rots
The old saying is true: One rotten apple can spoil the whole bunch. For the tree fruit industry, post-harvest rots in pome fruit (apples and pears) can result in losses of 50 to 60 percent in storage bins prior to packing, costing the industry millions of dollars annually.
Thanks to the research of Washington State University associate plant pathologist Chang-Lin Xiao at the Tree Fruit Research and Extension Center in Wenatchee, the industry is well on its way to significantly reducing losses due to rots caused by fungal pathogens.
Over the past five years, Xiao has discovered three new pathogens responsible for post-harvest rots in pome fruit in the United States. His reports on two of them were the first in the world and their causal agents have been described as new fungal species. They have been found to be responsible for as much as one-fifth of the losses resulting from postharvest decay in Red Delicious apples and one-third of the losses in d’Anjou pears in Washington state.
“These pathogens colonize while the fruit is in the orchard and remain latent until post harvest,” according to Xiao. “We’ve found that with appropriate pre-harvest or postharvest fungicide treatments we can significantly reduce the post-harvest rot problem.”
Xiao advocates better communication between orchardists and fruit packers to coordinate the different fungicide applications they use.
“Pre-harvest treatment is effective, and by reducing the need for post-harvest treatment, it also helps to avoid these pathogens developing resistance to post-harvest fungicides,” Xiao said.
Xiao’s research is also pursuing more effective treatments for two other common post-harvest diseases, gray mold and blue mold, which infect punctures and bruises on the fruit. He advocates keeping orchards clean of decayed fruit and organic debris to reduce the presence of the pathogens, good harvest management to avoid punctures and bruises on the fruit skin during harvest, and appropriate fungicide treatment for each.
“The goal of my research is to develop an integrated approach to pre- and post-harvest treatments to control pathogens,” Xiao said. “We are working to reduce losses that result from multiple diseases, not just one.”
Rotting Fruit