Sycamore Diseases

Disease	Symptoms	Pathogen/Cause	Management
Anthracnose	Dead twigs and branches have sunken cankers. Bud death followed by new bud formation and more bud death results in witchesbroom proliferation of branches as well as very crooked branching patterns. Black fungal fruiting structures are visible on the bark covering newly killed twigs early in the spring. Young shoots are killed. Leaves, especially on lower and inner branches, are blighted and fall early in the season only to be replaced by new leaves in mid-season. Tan, dead areas expand along leaf veins. Large, irregularly shaped areas are killed along the leaf margins and between the veins. Fungal fruiting structures can be found with a magnifying glass along the veins.	Apiognomonia	Prune and destroy dead twigs and branches during dormancy, cutting 3 to 4 inches below the canker. Plant resistant cultivars that have been vegetatively propagated from Bloodgood, Columbia, or Liberty clones of London plane trees. If trees are of high value, benzimidazole can be injected once in the autumn before the leaves have fallen to obtain protection of new tissue for the following two to three springs. Or, spray chlorothalonil, myclobutanil, copper, or mancozeb + thiophanate methyl in the spring at bud break and repeatedly until the weather dries and daily temperatures average above 65 degrees F.
Bacterial Leaf Scorch	Oldest leaves brown along their margins and eventually between the veins beginning mid to late summer on one branch or a few branches on the inner and lower portion of the tree. A brown band sometimes develops between the brown and green tissue of the leaf. The browning of leaves progresses to include more leaves toward the ends of branches. Infected trees have delayed bud break in the spring and produce smaller than normal leaves.	Xylella fastidiosum	Affected trees may take several years to die. No treatment is recommended.
Canker Stain	London plane and sycamore trees have sparse foliage, small leaves, and elongated sunken cankers on the trunk and larger branches. Beneath the cankers, the wood is stained bluish black or reddish brown in a wedge -shape (when viewed in cross section) with the point of the wedge extending toward the center of the trunk or branch.	Ceratocystis fimbriata f. sp. platani	Since the fungus enters only through wounds, pruning tools, ropes, ladders, and other equipment must be disinfested immediately after use on a tree before proceeding to another tree. Do not use wound paints since contaminated brushes efficiently move spores from tree to tree. Sap-feeding beetles can also transmit the fungus from plant to plant.
Powdery Mildew	Heavy white fungal growth develops on the upper surface of leaves in late summer and in the autumn. Leaf shape is very distorted.	Microsphaera	Little damage occurs to the tree itself other than deforming the leaf appearance. Benzimidazole injection (described under anthracnose) also gives some powdery mildew control. No control is recommended unless the tree is of very high value. Chlorothalonil, myclobutanil, cupric hydroxide, mancozeb + thiophanate methyl, or triadimefon can be applied in late summer to protect leaves.

Fungicides mentioned above:

COMMON NAME	TRADE NAME
benzimidazole	Arbotect
chlorothalonil	Daconil 2787
copper	Tenn-Cop 5E, Kocide, Phyton, Basicop
mancozeb	Mancozeb
mancozeb + thiophanate methyl	Zyban
myclobutanil	Systhane
triadimefon	Bayleton, Strike