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A beech canopy with beech leaf disease. NPS / Brolis.
Beech leaf disease is a new and spreading threat to beech trees, and in the Washington, D.C. region, where the beech is the most common tree, it matters a great deal. It is caused by a newly described nematode, Litylenchus crenatae mccannii, and it has look-alikes. Telling them apart is the first step in reporting it.
First, is it a beech?
Beech leaves (NPS / Vinduska) and bark (NPS / Sheline).
- oval leaves with toothed edges, arranged alternately on the twig
- leaves that turn yellow or bronze and hang on through the winter
- smooth, grey bark
Beeches keep their pale leaves into winter. NPS / John Zuke.
The disease and its look-alikes
| What the leaf shows | How to tell | |
|---|---|---|
| Beech leaf disease | dark bands between the veins, seen from below in the canopy; leaves wrinkled and misshapen, worse as it progresses | dark, orderly striping between veins |
| Woolly aphids | pale or yellow bands between the veins, sometimes pale spots | the bands are light, not dark |
| Beech erineum mite (Acalitus fagerinea) | dark spots of galls — small growth deformities | patchy spots, not organised bands; may be raised or lighter |
| Leaf-curling aphids (several species) | leaf edges curl; yellowing between veins | the curl, and cast aphid skins like small brown bumps under the leaf |
Beech leaf disease: dark banding, then browning and shrivelling. NPS / Brolis.
Woolly aphid damage: the bands are pale. NPS / Brolis.
Leaf-curling aphid damage. NPS / Brolis.
If you find it
- Report it to your county or state department of agriculture, and, for good measure, on iNaturalist.
- Ask an expert: local foresters or an ISA Certified Arborist can confirm it and advise.
Sources
Written from Hannah Harkness, "Beech Leaf Disease: Mistaken Identity", National Park Service National Capital Region Inventory and Monitoring Network, a work of the United States government in the public domain. The nematode was described by Carta and others, Forest Pathology (2020); see also the U.S. Forest Service's Pest Alert: Beech Leaf Disease (2022).
Dans ces collectionsChesapeake & Ohio Canal National Historical ParkAntietam National BattlefieldCatoctin Mountain ParkManassas National Battlefield ParkGeorge Washington Memorial ParkwayHarpers Ferry National Historical Park
Licence : CC0 1.0 (domaine public) · Adapté de www.nps.gov
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