Beech Leaf Disease (BLD) is an issue that is developed in whole or part by a foliar nematode (Litylenchus crenatae mccannii) (LCM). It was first discovered in 2012 in Ohio and has since spread to several different states and Canada. While much of the biology and impact of this pest remains poorly understood this a significant threat to beech trees, as it can kill a mature tree in as little as 6 years. Numerous studies are investigating the vectors of BLD, disease etiology and management of the nematode. Much remains to be learned about this new and destructive disease. While initial reports from the Midwest suggested that mature trees could withstand the disease for many years (Ewing et al. 2019), trees in southern New England are dying rapidly after infection. Additional stresses such as drought, winter injury, site-related stresses (poor, compacted soils and physical injury), twig/branch cankering fungi (e.g. Asterosporium, Botryosphaeria, Nectria, Phomopsis, etc.), ambrosia beetle infestation, and other insect pests and pathogens all help to accelerate the decline of infested trees.
Susceptible Hosts
All species of beech trees (Fagus spp)
- American beech (Fagus grandifolia)
- European beech (Fagus sylvatica)
Symptoms of Damage
- Dark, interveinal banding that emerged with new leaf tissue in Spring.
- As the disease progresses, and in areas of high infestation, the leaf tissue becomes leathery to the touch and appears wrinkled and distorted.
- As trees re-foliate, the new leaves may appear pale and chlorotic.
Biology / Lifecycle
- Beech leaf disease (BLD) is caused by the nematode Litylenchus crenatae ssp. mccannii.
- This nematode population increases as the summer progresses with peak populations active in the leaf tissue in August-September.
- Nematodes migrate from leaf tissue into the newly set buds during this timeframe.
- Once the nematodes enter the bud, they feed on the bud tissue throughout the winter – the damage seen in Spring is a result of this feeding.
- As the infestation and damage persist year over year, canopy thinning and ultimately death occurs, sometimes as quick as 5-6 years, even in mature trees.
Dark, interveinal banding is the most apparent symptom of BLD
BLD infection damage (5 years after initial detection)
Treatment Strategy/Expectations
Foliar sprays with fluopyram (e.g., Broadform®) have proven to be effective for control of BLD when applied multiple times and when no untreated beech trees are nearby. Because re-infestation happens readily and quickly, this management option should be reserved for specimen beech trees.
The use of phosphite based fertilizers (e.g., Dog-Phite) do not affect the nematode, but have been shown to aid in tree survival and recovery from BLD.
Macro-infusion of Arbotect 20-S have been found to reduce nematode populations for two and is an excellent option for managing BLD. Data show that infusions made between full leaf out and late July/early August bare the best results. 24(c) Special Local Need labeling is available for many of the affected states (check www.RainbowEcoscience.com for up to date 24(c) labels).
Beech being injected with Arbotect 20-S
| Product | App. Method | Dosage | Timing | Re-Treatment |
| Tree Injection (Macro-Infusion) | Apply 1.6oz of Arbotect per 1” of DBH Mix each 1.6 fl. oz. of Arbotect in 51.2 fl. oz of water | Full leaf expansion through late July/early August *Do not treat trees with thin or partial canopies early in the season | Application can be made once every two years. | |
| Dog-Phite | Soil Injection | Mix 1 quart per 100 gallons of water. Apply at 2-gals of solution per inch DBH | Spring and late summer | Applications can be made as needed. |
*Product is Rainbow Ecoscience’s industry standard recommendation for most industry situations.
Broadform is a registered trademark of Bayer Environmental Science
Tree Injection using Arbotect
Tree Injection with Macro Pump
Always refer to product label for rates and approved uses. Some images courtesy of forestryimages.org or Wikimedia Commons. Use of the images does not imply endorsement of treatments.
