Beech leaf disease: what the agencies record

This page reports what the official source says. It is not legal advice: ask the office named here. It lists what agencies and an extension service record about beech leaf disease and does not diagnose any tree. The pages read for it describe reporting requests and a request not to move certain material, and none of them describes a quarantine order. The list of other diseases is on the tree diseases page.

At a glance

Item	What the sources say
Name given with it	A nematode, Litylenchus crenatae mccannii. New York DEC says the disease is associated with it, and that the full cause and how it spreads are unknown.
Hosts	American beech. Ontario also lists plantings of European, Oriental and Chinese beech in North America.
First found	Ohio, in 2012 (New York DEC, the Forest Service abstract and Maryland Extension all say so).
Where reported	New York DEC lists Pennsylvania, New Jersey, Connecticut, Maine, Massachusetts, Rhode Island and Ontario, and says it has spread across western, central and southern New York. Ontario says it was first detected there in 2017 and is present in the lower half of southern Ontario.
Report to	New York DEC takes reports through its forest health reporting form or an online invasive species map. See also the United States report-a-pest guide and the Canada report-a-pest guide.

How the sources say it spreads

New York DEC says how it spreads is not fully known. Ontario describes tiny nematodes that feed in developing buds in fall and spring, which upsets how leaves form, and on the tissue between leaf veins in summer. It says numbers rise from spring to fall and that the nematodes overwinter in buds and leaf litter. It says there is some evidence for spread by wind, rain and insects. Maryland Extension says it is unknown how the nematodes reach new trees. Ontario lists beech seedlings, leaf litter and firewood as material not to move.

Symptoms by season as the sources state them

Spring to fall. New York DEC lists leaf striping, curling or a leathery texture, most easily seen by looking up into the canopy, from leaf-out in May until leaves fall in October. Maryland Extension says the banding is best seen from underneath looking up, and from the underside of leaves on saplings.
Early signs. Ontario lists dark-green stripes or bands between the lateral veins. New York DEC says in early infestations only a few leaves may be affected, and that one tree can hold both heavily affected and unaffected branches.
Later signs. Ontario lists leaves that are thick and leathery and may be yellow, curled or misshapen, leaves that drop early, and buds that fail to open. New York DEC lists reduced leaf and bud production. The Forest Service abstract lists interveinal greening, thickening, often yellowing, canopy thinning and mortality.
Time to death. Ontario gives two to five years for sapling-sized trees to die, and longer for older trees. Maryland Extension gives two to seven years after infection. New York DEC says the disease can kill beech of all ages, with younger trees appearing to die more quickly.

Look-alikes the sources name

New York DEC says a beech can show beech leaf disease and another problem at once, and lists these other conditions: beech bark disease, erineum patch, powdery mildew, anthracnose, beech blight aphid, beech leaf rolling aphid and marcescence, which it calls a normal feature of beech holding dead leaves through winter. It says it does not manage the other issues in its table. Maryland Extension says anthracnose can cause brown spots, dead tissue and curling but is not limited to the area between veins, that erineum patch is caused by mites and lacks the banding, and that the beech leaf rolling aphid can cause curling and yellowing between veins.

Lab confirmation

The pages read do not set a lab requirement. New York DEC says staff review the photos of symptoms, leaves, bark and whole tree sent with a report, and the Forest Service abstract describes how nematodes from leaves sent by the Ohio Department of Agriculture were identified by microscope and DNA markers.

What is said about treatment

New York DEC says several products are licensed in New York to treat the disease, that research on how well they work was under way, and that it points readers to a licensed arborist or its Forest Health Research Lab for the current treatment research. Maryland Extension, in a page updated October 21, 2024, says there is no known treatment. The two statements differ, so each is attributed here. For who may apply pesticides see the guide to pesticide licences.