A Rotten Problem
Post-harvest rot in stored apples and pears is a multi-million-dollar problem for Washington growers, but not all post-harvest problems start in the packing shed.
 Chang-Lin Xiao, a plant pathologist at the WSU Wenatchee Tree Fruit Research and Extension Center, has discovered three previously unidentifi ed pathogens responsible for causing post-harvest rot in apples and pears in the U.S. Two of his findings were the first in the world at describing a new fungal species. Post-harvest rot in stored apples and pears is a multi-million dollar problem for Washington growers. |
Chiang-Lin Xiao, a plant pathologist at the WSU Tree Fruit Research and Extension Center, has discovered three previously unidentified pathogens responsible for causing post-harvest rots in apples and pears in the United States, and he has found that the post-harvest problems started in the orchard.
“I am working to develop a holistic approach to the management of post-harvest diseases, from pre-orchard to post-production,” Xiao said. “It is a pre-harvest to post-harvest, integrated program.”
Hired as part of the state’s Safe Food Initiative (see related story in sidebar), Xiao started his research by conducting a statewide survey of post-harvest diseases in apples and pears in the state. Two of his findings were the first reports in the world and were described as a new fungal species. In 2006, he received the prestigious Lee M. Hutchins Award from the American Phytopathological Society for his work.
 Robin Boal, Xiao's scientific assistant. |
“As a result of his work, growers no possess information on appropriate chemistries for suppression of these decay pathogens when employed as a pre-harvest treatment in the orchard environment,” the society said. (For more on the impact of Xiao's research, visit Return on Investment.)
Washington State University has a long, rich history of working on post-harvest diseases in tree fruit and has built one of the strongest research teams in the country to deal with the issue.
Gene Kupferman, Extension post-harvest specialist, at the WSU TFREC, is a close and valued partner of the tree fruit packing industry in Wenatchee and throughout the state. He specializes in a number of areas, including temperature shock, scald prevention in Anjou pears, and applying antioxidants to prevent a naturally occurring chemical that contributes to post-harvest problems.
On the Pullman campus, Professor John Fellman is working on finding the chemical indicators for superficial scald severity – an economically devastating disorder – after storage. He also is conducting research on the “flavor regeneration“ phenomenon in apples removed from controlled-atmosphere storage.
Others on the Pullman campus involved in post-harvest research over the years include:
- Retired Professor Gary Hyde
- Professor Marvin Pitts
- Professor Juming Tang
- Professor Gustavo Barbosa
- Professor Max E. (Pat) Patterson
- The late Henry Waelti, WSU Extension Specialist
- Ralph Cavalieri, associate dean and director of the WSU Agricultural Research Center
- USDA-Agricultural Research Service scientist Ken Olsen
-Kathy Barnard
But Is It Safe?
E. coli in spinach, contaminated wheat gluten in pet food, bird flu—these are just a few of the recent headlines that have consumers worried about the safety of our food supply. Farmers have parallel concerns from pathogens that continually threaten the most basic components of the industry, the seeds and rootstock upon which grow the fruits of the field.
Counteracting such food safety fears is a nation-wide initiative that helps make Washington one of the most reliable sources of safe, high-quality food.
Funded by contributions from growers and grants from USDA, the National Clean Plant Network strives to supply growers with plant stock that is free of viruses and other diseases. As a regional partner, WSU works to keep the state’s agricultural industry competitive, economically viable and environmentally sustainable.
Electron microphotograph of apple mosaic virus. Photo: National Institutes of Health.
“This project is a very high priority for the university,” said Ralph Cavalieri, associate dean
and director of the WSU Agricultural Research Center. “It’s one of the most important things we do for the tree fruit industry.”
Unlike fungal and bacterial infections, viral diseases can’t be controlled using chemicals. And there’s no way to stop infection once it’s gained a foothold in an orchard. Keeping viruses out of the nation’s agricultural production chain thus depends on prevention and vigilant testing of plant DNA to detect pathogens.
It’s estimated that the Network’s efforts annually contribute $27 million to the U.S. economy by reducing loss and improving the availability of fresh produce. -Brian Clark
The yellow spots on this leaf are evidence of infection by the Pennsylvania isolate of plum pox virus. The leaf is from Chenopodium foetidum, an important indicator species of plum pox disease. Photo: Scott Bauer/USDA ARS.