Scientists stalk apple tree-killing disease
New York researchers are stalking a mysterious phenomenon that has been killing apple trees across North America.
Since 2013, a condition now named rapid apple decline (RAD) for its sudden onset has caused apple trees to quickly deteriorate and die across North America.
Two Cornell University scientists are on a mission to track down its cause, according to a news release.
The effort is bolstered thanks to a recent $299,000 grant from the U.S. Department of Agriculture’s National Institute of Food and Agriculture, the release said. The three-year project, “Root Traits and Rapid Decline of Apple Trees in High-Density Orchards,” is one of the first federally funded projects to research rapid apple decline in the U.S.
In Geneva, N.Y., two researchers at Cornell AgriTech first teamed up in 2018 to explore potential causes of RAD, such as pathogens, insects, cold weather injury and root systems’ interactions, the release said. While their findings revealed no direct above-ground causes, they noticed that a weaker root system could potentially contribute to the trees’ decline.
“So very little is known about the below-ground root system of apple rootstocks right now,” Awais Khan, co-principal investigator and associate professor of plant pathology and plant-microbe biology, said in the release. “By performing a comprehensive analysis of these systems, we are hopeful that this project will uncover the answers the apple industry has been looking for.”
Khan and Marc Fuchs, professor of plant pathology and plant-microbe biology, will hone in on the complex dynamics of apple root systems and explore the behavior of viruses in commercial apple orchards, according to the release.
Khan and Fuchs will be working with commercial growers in the Hudson Valley, Capital District and Lake Ontario regions to compare physical samples of both declining and healthy trees from different orchards and soil systems. They will also obtain trees from nurseries in New York state and beyond for analysis.
As part of his research, the release said Khan will explore a possible connection between high-density orchard systems and RAD. Fuchs will establish whether the presence of viruses in these nursery trees may weaken the root system of declining trees.
Khan and Fuchs, the release said, also will examine a wide variety of commonly used commercial apple rootstocks to determine whether there is a connection between RAD and specific rootstocks being used by growers.
“Ultimately, we want to help growers make good decisions about using cultivars that do not have viruses present on the right rootstock and in the right site,” Fuchs said in the release.
