IFTA Summer Tour: Cornell researchers showcase emerging orchard disease, weed and IPM tools

After finishing two days touring around the quaint farming villages and small towns surrounding New York’s Hudson River Valley, attendees of the 2026 IFTA Summer Tour settled in on the event’s final morning to learn about fruit tree-centric research projects undertaken by Cornell University, New York state’s designated land grant.

Starting things off was Scott Cosseboom, Ph.D. He presented on one of his current research projects: UV-C for disease management in the orchard.

Cosseboom said the UV-C spectrum of light — a more intensive wavelength than what we humans perceive with our eyes — is thought to be an emerging tool for defending fruit trees from yield robbing disease pathogens due its ability to “resonate with DNA and break it apart; it will burn/harm DNA and microbes.” 

Ultimately, he believes more research is needed before fruit growers start building out UV-C tow-behind rigs for their orchard tractors.  

His team’s UV-C work at the Hudson Valley Research Lab (HVRL) in Highland focused on two specific diseases: bitter apple rot and blister spot. Crist Bros. Orchards, one of the stops on the previous day’s bus tour, is also involved in the project as a testing ground for the treatments.

Cooseboom said in those trials, the UV-C treatment showed a positive effect on advancing fruit coloration in three varieties – Snap Dragon, Fuji and Ruby Frost – but a similar trial on Gala and Honeycrisp blocks showed no positive effect on disease pressure.

“There’s just a lot of research that still needs to be done,” he concluded.

Alternative weeding tech

Fellow Cornell researcher Mike Basedow says many specialty crop growers in New York are still in the early stages when it comes to looking at non-chemical weed control methods, driven primarily by the controversial pesticide Paraquat being phased out across the state.

In one trial, Basedow and the Cornell team looked at a rotating twine-type of mechanical weeding unit, known as a Rinieri SRL, vs. a traditional contact herbicide program in a Champaign Valley orchard. The implement was incorporated into the orchard’s traditional weed management program — so pre- and post-emerge herbicide passes were still applied — and the Rinieri was used later for any escapes.

“We did 5 full rows randomized throughout the orchard versus the control [just herbicide] and two passes of the [Rinieri] showed good control of weeds over a two-season data set,” Basedow said. “One limitation we ran into is orchard drip tape can make it tricky to get close to the trees, so you have to raise the irrigation lines.”

As with his colleague Cooseboom’s previous talk, Basedow also “can’t recommend it alone” without more evaluation, noting the program shows promise but is still more expensive than chemical control alone due to the cost of the machinery, labor and diesel.

IPM trap monitoring network build out

Dr. Anna Wallis, fruit IPM coordinator, gave an update on the statewide tree pest monitoring network she is coordinating with colleagues at Cornell. The network is up to 30+ monitoring locations and she’s publishing data from the traps in weekly blog posts.

“Growers can see trends in real-time and look at trap captures and decide on pesticide [application] timing,” she said, adding that the data can be viewed spatially across the entire state or drilled down to individual production regions.

One tidbit she shared is Spotted wing drosophila (SWD) is emerging early in New York and as soon as the pest emerges “that’s your sign to start spraying for it.”

Wallis is also spearheading a multi-channel grower outreach effort, along with her colleagues, on behalf of Cornell Extension. That undertaking includes a virtual tree fruit scouting course on Wednesday nights from February to March, several fruit pest fact sheets digitized for the web and live virtual IPM training on the Cornell IPM YouTube channel.

She is also involved in launching a pilot program that offers free on-farm trainings on Apple pest identification specifically geared to H-2A and farmworkers. Last year they held meetings on 17 different farms and interacted with 159 workers.

“The response to this program has been huge, the guys we’ve talked to have been engaged and want to participate,” she added. “We hope to continue that program and expand it to more farms.”

Pest baiting and UV-C for bugs

Cornell etymologist Andres Antolinez is bullish on a suite of new IPM  tools researchers are working on for growers.

One such tool he’s evaluating in research trials is using UV-C for pest control. In its simplest terms, he says basically “you burn the insect to death with UV-C.”

The UV-C treatments showed 20% more insect mortality than the control group in his trials, and a subsequent trial in a commercial orchard again showed what he called a significant decrease in the number of insect colonies versus the control blocks.

“The next step is more research to zero in on the right timing, frequency and long-term efficacy,” he said.

Antolinez is also working on a pest trending up among tree fruit growers on the East Coast: the invasive Spotted Lanternfly (SLF). The pest’s populations in New York “exploded” in 2025, he said, and even with conventional insecticides showing effectiveness, pre-harvest intervals remain a limiting factor to when and how often a grower can spray.

Researchers at Penn State University were among the first to observe the SLF’s preference for climbing tall structures. That development led Antolinez to hypothesize that “baiting” the tops of orchard trellis poles with UV-A light, which attracts SLF, and applying a long residual insecticide to netting atop the poles could result in better control.

His team went to work, attaching a UV-A light fixture to the top of a vineyard trellis poles in 3 different commercial blocks. The method showed it attracts and kills SLF but ultimately “it was not statistically significant compared to the control” Antolinez said.

His next step is optimizing the UV-A trap fixture, perhaps by increasing the intensity of the lights or using taller trellis poles, he added.

Last-but-not-least: NY Honeycrisp playbook

Researcher Dan Donahue has developed what he is calling the “Honeycrisp playbook,” which he says represents an “integrated systems of steps to take as growers to mitigate bitter pit in the Honeycrisp variety.”

Donahue added that currently there is “no easy answer, so far…there is no product you can pour out of a jug and spray to fix [bitter pit].”

Among growers in the state, there are currently two schools of thought on how to manage bitter pit, according to Donahue:

• Maximize calcium content to overcome the deficit.
• Focus on making apple trees able to transport minerals from the soil and foliar sprays more efficiently.

“It really is a nutrient versus plumbing problem: the calcium ion is quite immobile in plant production, so you need to focus on management practices that increases the plant’s ability to uptake and use the calcium cation,” he said.

Noting that bitter pit is a “terrible problem in New York’s Hudson Valley”, Donahue says there are several steps growers can take to mitigate its impact:

• Rootstock choice: According to the playbook, B9 has superior performance as a rootstock, while M9s and M26s had “far more bitter pit.”
• Apply the PGR Apogee at pink to throttle back vegetative growth: This will, according to Donahue’s research trials, minimize competition for calcium. “The single pink spray really cut down on bitter pit,” he said, noting a traditional three spray program actually increased incidences of bitter pit in Honeycrisp.
• Crop load management matters: In general terms, Donahue says usually with a light crop there will be more bitter pit pressure, and over cropped trees will produce smaller fruit with less bitter pit. A deep dive into three years of fruit size data that looked at 12,000-plus apples proved otherwise, though. “Grow 113s versus 80s, it helps,” he said. “We overplay size concerns but we have data that shows king fruits have less bitter pit than lateral fruits.”
• Apply calcium early and often: In fact, Donahue advises, do it weekly starting at petal fall.
• Irrigation management: You want plenty of water on your Honeycrisp trees early in the season, and then during the second half of the season you want some degree of water stress to help reduce bitter pit, he said.

-By Matthew J. Grassi, managing editor