New Fungi on N.Y. Apples

Apple Bitter Rot

Hudson Valley apple orchards have a growing new worry on their hands. Scientists have identified a pair of fungal pathogens not previously known in the region that cause the disease dubbed “bitter rot” — which, as the name suggests, causes warm-weather fruits to decay and die. The new species were found infecting fruits both in the field and in storage. And it’s only likely to get worse. 

Apple Bitter Rot (Photo by Srdjan Goran Acimovic)

The team behind the discovery, led by plant pathologists at Cornell University, says bitter rot in New York has been known to wipe out upwards of 20 percent of a given orchard’s crop on average, and local incidence has been steadily rising in recent years. For organic farms, the losses could be as grave as 100 percent. 

A Known Fungus Makes Its Debut in New York

It’s a new development for a familiar foe; bitter rot, brought on by fungi from the genus Colletotrichum, has long wrought devastation on fruiting plants all over the world, from apples and peaches to papaya and citrus. Of the newly identified species, the researchers say one (C. chrysophilum) shouldn’t even be in apples at all, as it’s typically known to infect tropical and subtropical fruits like bananas and cashews. 

“Not anywhere in the world has this species been described as a pathogen of apples,” Srdjan Acimovic, of Cornell AgriTech’s Hudson Valley Research Laboratory and senior author on the paper, told Scenic Hudson. 

But that’s not the most baffling part of the discovery. The second species the researchers identified is entirely new to science, meaning it has never been described before in any capacity. “It was shocking to us,” Acimovic said. “We were confused.”

Finding one species in an extremely abnormal host seemed peculiar enough, though the unprecedented weather conditions of the past few years — particularly in 2016, 2017, and 2018 — could provide some explanation, but finding a new species altogether seemed almost inconceivable.

“People didn’t believe us,” Acimovic says. “We had longstanding indications” that what they’d found was indeed a new species, he explained, “but we had to prove it.” And they did. 

An Unknown Fungus Is Identified and Named After New York

The team, collaborating with researchers from Pennsylvania State University, the Canadian Food Inspection Agency, and Louisiana State University, sampled apples from roughly 20 farms, including a handful out of state, and was able to isolate the disease-causing fungi in 400 separate cultures. Then, the researchers sequenced the entire genome of the new species to map out what is, essentially, its “DNA fingerprint.”

“Our collaborators all over were like, ‘You were right, this is not a known species,’” Acimovic said. 

The new species of fungus is called C. noveboracense, after the Latin name for New York.

By characterizing the species as they did, the researchers now have a better shot at understanding its ability to infect and how best to fight it. “We can learn so much from that blueprint,” Acimovic said.

Whether or not these new pathogens stick around remains to be seen. There are many factors that will play into their persistence (or lack thereof), including management and weather conditions, and there’s no telling just yet what climate change will mean for it all. Conditions in the Hudson Valley are already somewhat favorable for a disease like bitter rot; the area along the Hudson River Basin represents the largest “pocket” of a hot, humid summer continental climate in this region, the researcher explained, alongside smaller swaths along Lake Ontario and the Finger Lakes. 

These are “warm weather pathogens,” Acimovic notes, and the rising trend of higher temperatures and heavier rainfall in recent years certainly is “fitting the pattern.”

Cornell runs an outreach program to connect local growers with resources and technical assistance. Farmers in the Hudson Valley who think they might be affected by bitter rot can contact Cornell Cooperative Extension specialist Dan Donahue for support.

Tackling Ticks

Rick Ostfeld holding a white-footed mouse

Enjoying outdoor exercise helps boost our immune system and relieve stress, which has never been more important. But while a walk in the woods may keep you healthy on one hand, it also makes you a prime candidate for contracting Lyme disease.

Tick-borne illnesses have doubled since 2004, and New York ranks second only to Pennsylvania in the number of cases, with the lion’s share occurring in the Hudson Valley. Fortunately, Millbrook’s Cary Institute of Ecosystem Studies is at the forefront of efforts to halt this scourge.

In 2016, the institute partnered with Bard College, the U.S. Centers for Disease Control and Prevention, NYS Department of Health, and Dutchess County Department of Behavioral and Community Health to kick off the Tick Project. Headed by Cary disease ecologist Richard Ostfeld and Bard biologist Felicia Keesing, the five-year study will determine if a neighborhood-based method of tick prevention can prove effective and safe — for people, pets and the environment.

Ongoing in 24 Dutchess County neighborhoods, the study focuses on testing the effectiveness of two pesticide-free methods to reduce tick populations. One, the Tick Control System, consists of a small box that attracts mice and chipmunks, both primarily responsible for infecting ticks with Lyme bacteria. Rodents entering the box receive a low dose of the same chemical in your dog or cat’s tick-killing collar. In the second method, a naturally occurring fungus that kills ticks is applied to vegetation. The two methods are being tested separately and in tandem.

To date, researchers have completed more than 24,000 surveys in the neighborhoods. At the end of 2020, the partners began analyzing and synthesizing these and all remaining results. Eventually, the partners hope to recommend strategies for municipalities, community groups, and others to take a bite out of Lyme disease.   

In the meantime, enjoy this compelling video presentation by Dr. Ostfeld that contains info about the Tick Project and Lyme disease in general.