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Caption: Sycamore anthracnose leaf symptoms
Photo by: R.S. Byther
  
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Sycamore : Sycamore anthracnose
(revision date: 4/11/2018)


Biology
Sycamore anthracnose is a fungal disease affecting buds, leaves, and shoots. Young leaves appear brown and crinkled, with small to large dead areas often occurring along the main vein or on leaf margins. Infected leaves often drop from the tree, sometimes resulting in severe and repeated defoliation. Twigs and branches can develop infections as well, causing twig dieback. Regrowth at the base of killed twigs often results in a witches' broom symptom. The disease is favored by wet weather in the spring, which spreads infection from twigs to emerging leaves. California sycamore (Platanus racemosa) and American sycamore (P. occidentalis) are particularly susceptible.
Management Options

Non-Chemical Management
  • Provide proper culture. Healthy trees are more tolerant of leaf loss and recover more quickly.
  • Rake and destroy fallen leaves.
  • Plant anthracnose-resistant species and cultivars. The London plane tree (Platanus acerifolia) cultivar 'Bloodgood' is moderately resistant. The oriental hybrids (P. occidentalis x orientalis) 'Columbia' and 'Liberty' are also resistant.
Select non-chemical management options as your first choice!

Chemical Management


Apply fungicides when buds swell and when bud caps begin to break. Apply again 10-14 days later (a 14-day interval is required for Spectracide IMMUNOX). Homeowners should not make foliar applications to trees over 10 ft tall. Consult a commercial pesticide applicator for treatment of trees and shrubs over 10 ft. tall.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.
  • Bonide Fung-onil Multi-Purpose Fungicide Conc
    Active ingredient: chlorothalonil  |  EPA reg no: 60063-9-4
  • Ortho Max Garden Disease Control Conc
    Active ingredient: chlorothalonil  |  EPA reg no: 239-2522
  • Spectracide IMMUNOX Multi-Purpose Fungicide Spray Conc
    Active ingredient: myclobutanil  |  EPA reg no: 9688-123-8845
  • This list may not include all products registered for this use.
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Caption: Sycamore anthracnose leaf symptoms
Photo by: R.S. Byther
Caption: Sycamore anthracnose witches' broom symptom
Photo by: R.S. Byther