$3.29 million effort keeps onions, garlic safe from pest and disease threats

Head and shoulders shot of Pappu in front of plant pathology specimen case.
Hanu Pappu, Chuey Endowed Chair and Samuel H. Smith Distinguished Professor with the Department of Plant Pathology, lead a multistate team researching sustainable defenses for allium crops.

Adding flavor to our plates and antioxidants to our diets, onion and garlic are among the most valuable vegetable crops in the world, with an annual value of more than $1.5 billion.

But U.S. crops are threatened by tiny insect pests carrying viral diseases that weaken and collapse onion and garlic plants, reducing yields and costing growers millions.

Hanu Pappu, the Chuey Endowed Chair and Samuel H. Smith Distinguished Professor in the WSU Department of Plant Pathology, is leading new research on sustainable ways to stop these serious pests and diseases.

Funded by a $3.29 million grant from the USDA National Institute of Food and Agriculture’s Specialty Crop Research Initiative, Pappu leads a multi-state effort developing tactics that could save the industry millions in losses.

Spearheaded by WSU, the project includes four years of research, and three separate research components with investigators from USDA’s Agricultural Research Service, New Mexico State University, Oregon State University, Cornell University, College of Idaho, and University of California’s Division of Agriculture and Natural Resources. The multidisciplinary research and Extension team includes plant pathologists, entomologists, breeders, and an economist, sociologist, and food scientist. At WSU, Pappu is joined by Extension entomologist Tim Waters.

Wilted onions in a field.
An onion seed crop, affected by the Iris yellow spot virus, transmitted by an insect pest. Grant-funded research at WSU helps find sustainable ways to protect allium crops from pests and diseases.

Together, the team will develop improved integrated pest management tactics to control pests and the diseases they carry, keeping onions — America’s third-most consumed fresh vegetable — growing more economically and sustainably for growers and consumers.

Scientists will work to cut down on pesticide use to control thrips, a tiny insect pest of alliums, while developing crop varieties that are resistant to the pest and the destructive virus they carry, Iris yellow spot virus, IYSV for short.

For most of his career, Pappu has studied IYSV and related viruses, making significant progress in understanding its disease cycle.

“IYSV has been a major constraint to seed and bulb onion production in the Northwest,” he said. “We are going to build on what we know about these pests and diseases to devise eco-friendly management tactics.”

His project also uses innovative approaches to reduce the problem of white rot, a disease of alliums that can survive in soil for up to 20 years, and has wiped out thousands of acres of onion and garlic fields in recent years.

“This work was developed in close consultation with onion and garlic stakeholders, and their support is critical for our success,” said Pappu. “Federal support lets us take our research efforts to the next level.”

Learn more about the project here.