Summer 2020

As if our cherished, wonderful beech didn’t have enough to contend with — warming temperatures and decreased growth as a species, bleeding canker (phytophthora citricola), beech bark diseases, and nectria — here comes a new pest that is emerging as a lethal disease for American and European beech trees. Beech Leaf Disease (BLD) is a new disease that has been observed in all cultivars of beech trees in the Eastern USA and Canada.

Symptoms of BLD include shriveled leaves with black stripes (see images) that start to die all the way up to the canopy of the tree. After a few years of being infested, leaves get deformed, chlorotic and have a thickened leathery texture. The capacity of the tree to produce carbohydrates through photosynthesis is greatly compromised, making it weak to insects and fungal cankers.

The cause of BLD is still being studied but scientists think it could be Litylenchus crenatae, a foliar-feeding nematode (a microscopic worm). These namatodes can move in shallow water or hitch a ride on anthropods like spider mites to spread locally. It has been suggested that they even travel on birds over long distances and spread the disease.

Preventive and therapeutic treatments for BLD are still in the early stages but avoid moving beech trees from areas where there are known infestations in the meantime to prevent its spread. Even people who are studying the disease have been advised to sanitize their shoes and clothing so as not to spread the spores.

Help us in helping the researchers by reporting this symptom if seen in your beech trees. Please contact your local Almstead Branch Office.