Extreme Microbe May Protect Washington Apples

WSU researcher develops compound to combat fire blight and Listeria in orchards and packing facilities

Apr. 11, 2026 at 4:46am

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A highly structured abstract painting in soft, earthy tones featuring sweeping geometric arcs, concentric circles, and precise botanical spirals, conceptually representing the complex biological forces and molecular structures of a new compound that could protect Washington apples from fire blight and Listeria.A new compound derived from an extreme microorganism could provide Washington's fruit growers with a powerful, natural tool to combat devastating orchard and packing line pathogens.Pullman Today

A compound derived from an extreme microorganism could soon provide Washington fruit producers with a new weapon to combat two of the most economically damaging pathogens facing the fruit industry - fire blight and Listeria. WSU researcher Cynthia Haseltine has spent nearly a decade developing and testing the compound, which has shown promising effectiveness in laboratory settings against a variety of harmful pathogens. The compound has several traits that make it promising, including stability across a wide range of temperatures and conditions, and a low chance for resistance developing compared to antibiotics.

Why it matters

Fire blight can wipe out entire orchards and is among the most serious threats facing Washington's tree fruit industry, which produces nearly two-thirds of the nation's apples. Losses attributed to the disease exceed $100 million annually nationwide. Listeria is also a major economic problem in packing lines, with recalls costing between $5 million and $15 million. This new compound could provide a more effective and environmentally-friendly solution to combat these costly threats to the Washington fruit industry.

The details

Haseltine, an associate professor at WSU, has dedicated her career to studying archaea, microorganisms known for their ability to thrive in extreme environments. One of those microorganisms is key to her compound, which has shown promising effectiveness against fire blight and listeriosis in laboratory settings. The compound remains stable across a wide range of temperatures and conditions, and has shown effectiveness against pathogens within biofilms. Field testing is already underway through partnerships with WSU Extension, with orchard trials led in Wenatchee and packing-line trials in Prosser.

  • Haseltine has spent nearly a decade developing and testing the compound in her laboratory.
  • The Washington Tree Fruit Research Commission recently awarded Haseltine a $141,293 grant to evaluate the compound's real-world potential against fire blight and Listeria over the next two years.

The players

Cynthia Haseltine

An associate professor in the WSU College of Veterinary Medicine's School of Molecular Biosciences who has dedicated her career to studying archaea, the microorganisms key to her new compound.

Washington Tree Fruit Research Commission

An organization established by the Washington state Legislature in 1969 that funds industry-driven research aimed at improving the production, handling and marketing of Washington tree fruit.

Tianna DuPont

A WSU Extension tree fruit specialist leading the orchard trials of Haseltine's compound in Wenatchee.

Claire Murphy

A WSU Extension food safety expert in Prosser providing Listeria isolates and additional expertise for the packing-line trials of Haseltine's compound.

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What they’re saying

“This work has the potential to make a real difference for Washington's tree fruit industry. If it performs as expected, it could help growers better manage fire blight in orchards while also reducing costly Listeria risks in packing facilities.”

— Cynthia Haseltine, Associate Professor, WSU College of Veterinary Medicine

“There's a really low chance for resistance developing. For that to happen, it would require multiple simultaneous mutations that are, statistically, very, very unlikely, whereas antibiotic resistance is often a single mutation.”

— Cynthia Haseltine, Associate Professor, WSU College of Veterinary Medicine

“Moving this out of the lab and into real-world conditions is a critical step. We need hard data from trees and from listeria in packing-lines to understand how the compound performs and whether it can become a practical tool for growers.”

— Cynthia Haseltine, Associate Professor, WSU College of Veterinary Medicine

What’s next

The two-year project funded by the Washington Tree Fruit Research Commission grant will focus on scaling production of the compound, evaluating its stability under different environmental conditions, and conducting the first orchard and packing-line trials.

The takeaway

This new compound derived from an extreme microorganism has the potential to provide Washington's fruit industry with a more effective and environmentally-friendly solution to combat the costly threats of fire blight and Listeria, which have plagued the state's apple and other tree fruit production for years.