Transcript ANTHRACNOSE - Upper Bucks County Technical School

May infect leaves, twigs,
buds, shoots, and even
the fruit of various
landscape trees
Anthracnose may
cause defoliation
on most maple,
oak, elm, walnut,
birch, sycamore,
and hickory trees.
Occasionally, it can
affect ash and
linden trees.
Raking and removing
infected leaves will
remove the main source
of spores that could
infect the tree next
spring
APPLE SCAB
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Most severe during spring and early summer
when the humidity is high and the temperature
is moderate
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Most obvious symptoms occur on leaves and
fruit in the spring and summer, and look like
small velvety brown-olive green spots that
enlarge and darken to become more or less
circular
BLACK SPOT
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Roundish black spots with fringed margins that
can be up to ½’’ in diameter
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Spots form on the upper sides of leaves
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The disease is caused by a fungus called
Diplocarpon rose
• To control black spots,
rake fallen leaves and
remove infected canes
• Avoid wetting leaves
when watering and
maintain air circulation
around within the
plants to promote
drying
BOTRYTIS
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Found virtually everywhere plants are grown
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Can attack many different types of plants
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Signs of Botrytis:
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Fading flowers
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Leaves on which fading infected flowers have fallen
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Broken stems or injured leaves
MANAGEMENT
 Remove dead or dying tissue from the
plants and from the soil surface
 Heat and ventilate greenhouses to
prevent high humidity conditions
 Avoid injuring plants in any way
o Commonly called gray mold
Symptoms
 Brown/reddish lesions on the
bark of trunks or branches, or
as injured areas on smaller
twigs
 New leaves appear smaller
than normal, often curled or
sparse, and pale
green/yellow/brown in color.
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Common, widespread, and destructive to a wide
range of trees and shrubs
Management
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Keep plants healthy through proper planting,
mulching, watering, soil management, pruning,
and winter protection practices
• Do not prune when bark is wet
• Avoid all unnecessary bark wounds
Control
• Fungicides
• Using resistant
varieties
 Can defoliate trees and blemish fruit making them
unmarketable
 Before an apple can be infected, adequate moisture
must be present in a temperature range from 46-75F to
allow for formation of basidiospores on cedar galls
• Leaves are most susceptible
to infection when 4-8 days of
age
• Fruit are susceptible from tight
cluster through bloom
CROWN GALL
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Can infect a wide range of herbaceous and woody plants
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Usually restricted to the roots, lower stems, and lower branches of infected plants
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Caused by the soil-borne bacterium Agrobacterium tumefaciens
Management
• Avoid wounding plants near the soil line
• Prune infected plants (Disinfect cutting tools
between each cut)
FIREBLIGHT
 A bacterial disease that can kill branches and whole plants of
many members of the rose family, including apple, pear,
quince, and crabapple
 Can be spread by insects, splashing rain or contaminated
pruning tools
Management
• Pruning (Sterilize all tools after each cut)
• Chemical Sprays
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Symptoms
Dead branches
Water-soaked
blossoms
Light brown/blackened
leaves
Discolored bark
Black “shepherd’s
crook” twigs
Dried fruit
Management
• Avoid overhead watering
• Remove and destroy all
infected plants
• Prune overcrowded material
• Looks like powdery splotches of white or
gray, on the leaves or stems of plants
• Different powdery mildew fungi infect
different plants
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Causes
Dampness
High humidity
Crowded plantings
Poor air circulation
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Lilacs, crab apples, phlox, monarda, roses,
grapes, squash and cucumbers are all likely
targets for powdery mildew
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 Plants affected by root rot will start losing
their leaves, yellowing, drooping, and look
like they’re dying
 Affected plants will drink less water
Management
• Keep growing area
clean
• Add beneficial
bacteria to the water
• Try to get as much
oxygen as possible
dissolved in the water
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Symptoms
Appear overwatered
or droopy
Brown, slimy, smelly
roots
Plant leaves start
turning yellow
Plants drink much less
water than usual