The University of Maine had a large presence at the 2024 Maine Ag Trades Show, not only through their exhibiting booths but also through their leadership in the educational sessions.

One of their presentations focused on the plant diseases that were discovered at the UMaine Plant Disease Diagnostics Lab throughout 2023. Director of the Plant Disease Diagnostics Lab Alicyn Smart and one of her laboratory technicians, Ruby Bonilla, talked about the new plant diseases discovered in Maine last year.

Smart, Bonilla and the rest of the research team’s goals are to complete various tests on the plant samples to narrow down what the pathogens may be until they have clear answers and can provide recommendations to remove them.

The UMaine Plant Disease Diagnostics Lab collects samples not only from Maine farmers but also from surrounding states, as they are the Regional Center for the Northeast Plant Diagnostics Network. Samples from the Maine to Maryland region. There is only an extra small fee associated with sending in samples from outside of the Pine Tree State.

Alicyn Smart, director of the Plant Disease Diagnostics Lab at UMaine (left) and Ruby Bonilla, a lab tech, talked about the issues facing Maine. Photo by Kelsi Devolve

When submitting a sample to the lab, there are two main ways to do so: physical and digital submission. In 2023 alone, there were 829 physical samples submitted and 400 digital samples (uploading photos). No matter which type of sample is submitted, “it’s really important to provide as much information as you can,” stated Smart. “The more plant material [submitted], the better.” (It’s best to submit the whole plant, when possible.)

Additionally, there is a third way to diagnose these plant diseases that eliminates having to ship a sample to the lab. There are plant disease identification boxes available for purchase online that walk you through how to culture the plant material yourself. This is an ideal method if you have limited plant material available, or if the material is prohibited from being received by the lab (such as cannabis).

With over 800 samples submitted in 2023, the top three hosts were 264 potato samples (keeping in mind the lab does research on potatoes), 115 garlic seed samples and 50 apple samples.

There were multiple new plant diseases discovered in Maine this past year: Bacterial crown gall on Euonymus (spindle tree), Rosellinia herpotrichoides (Rosellinia needle blight), apple skin scar viroid (which causes scarred skin or dapple symptoms in apples, making them unmarketable), beech leaf disease, dahlia mosaic virus and “suspected” petunia vein clearing virus (there is currently no way to confirm this disease).

Although apple skin scar viroid, beech leaf disease and dahlia mosaic virus are not technically new to the state of Maine, this was the first time their presence was confirmed through molecular diagnostic testing.

For more information about submitting a plant sample, visit

by Kelsi Devolve

Country Folks New England representative Kelsi Devolve (NH), Country Folks remote representative Fred Mang and wife Linda Mang (NY) represented Country Folks and Lee Newspapers at the 2024 Maine Agricultural Trades Show. Photo by Fred Mang


Country Folks New England’s Kelsi Devolve connects with a staff member at Fedco Seed’s booth regarding advertising to the agricultural and horticultural industries. Photo by Fred Mang