Symptoms of <a href="https://en.wikipedia.org/wiki/Phytophthora_kernoviae" class="extiw" title="en:Phytophthora kernoviae">Phytophthora kernoviae</a>. A fungal-like disease which affects some tree species. Picture shows an infected <a href="https://en.wikipedia.org/wiki/Rhododendron_ponticum" class="extiw" title="en:Rhododendron ponticum">rhododendron</a> leaf.
<a href="https://en.wikipedia.org/wiki/Forestry_Commission" class="extiw" title="en:Forestry Commission">Forestry Commission</a>
OGL v1.0
<a rel="nofollow" class="external text" href="http://www.forestry.gov.uk/forestry/infd-66jfng">Forestry Commission</a>