Discover CALS

See how our current work and research is bringing new thinking and new solutions to some of today's biggest challenges.

  • Cornell AgriTech
  • School of Integrative Plant Science
  • Plant Pathology and Plant-Microbe Biology Section
  • Fruits
Anna Wallis is a graduate student studying under the guidance of Kerik Cox, professor in the plant pathology and plant microbe-biology section of the School of Integrative Plant Science.

What drew you to the program at Cornell AgriTech?

Apples! I’ve been working with tree fruit since I was an undergraduate at the University of Maryland, and I was previously a regional apple specialist with Cornell Cooperative Extension.

Not only is New York the second largest apple producing state in the country, but Cornell, as a land-grant university, has a particularly strong tree fruit program. I was excited for the opportunity to work with some of the world’s foremost apple experts at Cornell’s AgriTech campus.

I was specifically drawn to Kerik Cox’s program, which is known for its cutting-edge, grower-supported research, as well as the supportive and entertaining work environment. There is never a dull day in our lab group!

What’s the focus of your research?

My main work relates to fire blight, which is caused by the bacterial pathogen Erwinia amylovora.

The disease looks like it sounds. When the bacteria infect a tree, the tips of newly growing shoots and flowers wilt, and then turn brown or black, making it look like the tree has been burnt. These bacteria are tiny but ruthless—under the right conditions, they are capable of killing trees in just a few weeks and capable of taking out entire orchard blocks in a single season.

Fire blight is one of the most significant diseases affecting tree fruit production around the world. My goal is to use both applied and basic research to develop more sustainable ways of managing the disease.

My primary project involves evaluating spray programs by using a plant growth regulator instead of antibiotics. I’m also working on strain tracking to understand how the bacteria move locally and regionally, and I’m trying to understand factors that may contribute to antibiotic resistance in orchards. 

What’s the most important scientific impact you’ve made as a graduate student?

One of the main goals of my work is to improve sustainable management practices in the tree fruit industry. Last year, Kerik Cox and I were awarded two regional grants (NE SARE and NYFVI) to do just that. Both projects involve conducting on-farm research trials throughout the state, specifically related to fire blight management.

This season it was rewarding to do site visits and work with the growers to test some of our research findings on their commercial operations. I firmly believe that doing these on-farm, collaborative trials is an essential step toward grower adoption of better management practices.

What fascinates you most about the tree fruit industry in New York state?

I have always been impressed with how knowledgeable and hardworking the fruit growers are. Modern apple production is a high-tech, high-risk endeavor, and it takes a wide range of knowledge and experience in horticulture, disease and pest management—not to mention business and regulatory know-how—to be successful. High density systems can cost upward of $20,000 per acre to establish, and even when everything goes well, they don’t payoff for years.

From tree training to crop load management to disease, perennial crops like apples have so many moving pieces to manage, and you often have to get things right on the first try. Whenever I feel tired from all the responsibilities of being a graduate student, I remember that the growers are working much harder, and they certainly have more at stake because their land and their livelihood depend on their overall success.

Keep Exploring

Kenong Xu stands in an orchard and measures a weeping apple branch in an orchard at Cornell AgriTech


Plant geneticists have identified a mutation in a gene that causes the “weeping” architecture – branches growing downwards – in apple trees, a finding that could improve orchard fruit production.

  • Cornell AgriTech
  • School of Integrative Plant Science
  • Horticulture Section
(L-R) Fred Frank, Richard Ball, and Hans Walter-Peterson survey vineyard damage along Keuka Lake


Following a mid-May freeze, two Cornell viticulture experts are advising grape growers in New York on how to rescue their season, as vineyards now face a reduced crop and economic loss.

  • Cornell AgriTech
  • Cornell Cooperative Extension
  • School of Integrative Plant Science