Beech Leaf Disease In connecticut
What causes beech leaf disease (BLD)?
We understand the foliar nematode causes BLD. However, the origin of the nematode and its distribution mechanism is unclear. In 2019, a closely related subspecies was discovered in Japanese Beech trees in Japan. Research is currently focusing on the nematode relying on a vector for transmission of BLD. The nematode requires water films to move outside of the leaf. Once outside, it is posited that they attach themselves to a vector. Vector options include birds, such as Blue Jays and Finches, insects, mites, and mammals. Additional research is being conducted into the lifespan of the nematode and whether it can survive in the digestive tract of a bird.
What are the signs?
The signs and symptoms visualized on beech foliage are best observed from the ground, looking into the canopy and against the light. We do know that in the Spring, emerging leaves can be infected by the pathogen, the foliar nematode. The most common observation of BLD is a direct striping between leaf veins. However, due to the severity of the disease in 2022, additional symptoms can include aborted leaf enlargement, cupping, browning and yellowing of foliage; branch and tip dieback, and, premature leaf drop.
(Dr. Robert Marra, 2021)
Where did it come from?
It is not fully understood where BLD was first introduced into the United States. BLD affects American, European and Japanese Beech trees.
When did it get to the US?
BLD was first identified in Ohio in 2012 and has since been discovered in Pennsylvania, New York, Ontario (Canada), Maine, Connecticut and Rhode Island.
When did it get to CT?
BLD was first detected in lower Fairfield County in August 2019.
The development of Beech Leaf Disease throughout the the years.
Is my tree going to die?
We are unsure. Saplings and young trees are more susceptible to the disease and can die within three years after symptoms are observed. Consequently, this can reduce the proportion of American Beech trees in the affected forest and landscaped areas. We also know that the severe symptoms have been exacerbated by the record heat and drought of the 2020 Summer and in the dry 2021 Spring.
(Beech Leaf Disease – Updates 2021. Yonghao Li and Robert E. Marra)
Healthy
VS
Diseased
Is there a cure?
No. There is no cure. This is likely due to there being little known about the pathogen's biology and the invasive disease's epidemiology. We have only been aware of BLD for approximately nine years and have only been researching the disease and causation in Connecticut for the last two years.
The good news…
Currently, CAES has joined forces with a multitude of researchers spanning Ohio, Pennsylvania, New York, Ontario (Canada) and USDA – ARS. These researchers are currently studying disease development, transmission and control. Their primary focus is to monitor and categorize locations and symptoms of BLD on beech trees throughout the researched areas. In addition, research on control options conducted in Ohio has shown some promise of recovery after five years of treatments with a phosphonate-based product.
