Symptoms and Diagnosis
is group related fungal diseases that infect shade
trees, oaks, ash, walnuts and sycamore. Each fungus is
specific to its host tree it affects. For example, the
oak anthracnose fungus affects only oak and will not
spread to other genera of trees or plants.
Ideal conditions for anthracnose is cool
wet weather conditions of spring and early summer.
Leaves develop irregular shaped leafspots which often
coalesce to form large blotches which cover much of
the leaf surface and are limited only by the midvein.
Anthracnose diseases generally infect the leaf veins
and cause death of the vein and surrounding tissue,
which becomes papery thin and falls away, giving the
leaves a tattered look. Defoliation occurs
particularly on ash and red oaks which is
characteristically drop a large number of affected
Anthracnose outbreaks subside with the
onset of warmer summer temperatures and reduced
moisture. Serious damage does not occur on well
established trees since occasional defoliation seldom
has a long-lasting impact on tree health. Trees will
produce a second flush of leaves with out experiencing
severe stress. Repeated defoliation for several years
in succession may weaken trees and result in limb
dieback. In most cases, active disease management
practices are not warranted since the disease does not
occur every year and the health impact is minimal.
Rake up and
destroy (burn) or properly dispose of infected leaves
in the spring and well as the fall leaves since the
fungi over winter of infected leaves.
Prune to remove diseased twigs and
branches and open up the canopy for better air
circulation and light penetration. Remember sterilize
pruning tools with a Clorox solution of one part water
or ammonium chloride, Consan 20, a triple action
Avoid wetting tree
foliage with sprinklers by reducing the spray
Maintain good tree vigor by proper
watering practices during dry periods, mulching and
also periodic fertilization when necessary.
with a copper sulfate fungicide, Daconil, or Banner
preventative, not curative measures and apply
according to label instructions, when the leaves are
beginning to enlarge at bud break. Reapply spray
7 - 10 day intervals for two or three more