Horse Chestnut Leaf Blotch Research Paper

Horse Chestnut Leaf Blotch is caused by fungi called Phyllosticta sphaeropsoidea (syn. Guignardia aesculi, Phyllosticta paviae) infecting the Horse chestnut and Buckeye trees. In spring, discoloured, water-soaked spots are the first to appear. By mid to late Summer, reddish or dull brown, irregular blotches, sometimes with a yellow margin, and with tiny, black, spore-carrying, fruiting shapes within the blotches, appear on the leaves. The Horse chestnut leaf blotch lays dormant during the winter in fallen leaves, and releases its fruiting spores during the wet weather in Summer.
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The appearance of the Horse chestnut tree is unattractive with the leaf blotch. Young trees are vulnerable and can sustain severe harm.
Injury to a mature tree is of a less serious nature, because of the late season infection affording the mature tree time to develop and grow strong. Important to note that this fungus is much more damaging during years with heavy rains.

Control Horse chestnut leaf blotch in the Fall, by raking fallen leaves from the ground as soon as possible after they fall, and disposing of them either in the compost, by removing them, or by burning to stop any dormant infections. Properly prune branches to allows for air circulation. Keep pruner clean during each cutting to lower chances of infection. Water the roots of the tree in the morning, and mulch to keep moist.