ANTHRACNOSE Anthracnose may cause defoliation on most maple, oak, elm, walnut, birch, sycamore, and...
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Transcript of ANTHRACNOSE Anthracnose may cause defoliation on most maple, oak, elm, walnut, birch, sycamore, and...
ANTHRACNOSE
Anthracnose may cause defoliation on most maple, oak, elm, walnut, birch, sycamore, and hickory trees. Occasionally, it can affect ash and linden trees.
May infect leaves, twigs, buds, shoots, and even the fruit of various landscape trees
Raking and removing infected leaves will remove the main source of spores that could infect the tree next spring
APPLE SCAB• Most severe during spring and early summer
when the humidity is high and the temperature is moderate
• 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• Roundish black spots with fringed margins that
can be up to ½’’ in diameter
• Spots form on the upper sides of leaves
• 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• Found virtually everywhere plants are grown
• Can attack many different types of plants
• Signs of Botrytis:
• Fading flowers
• Leaves on which fading infected flowers have fallen
• 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
CANKER
• Common, widespread, and destructive to a wide range of trees and shrubs
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.
Management• 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
CEDAR-APPLE RUST
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
Control• Fungicides• Using resistant
varieties
CROWN GALL• Can infect a wide range of herbaceous and woody plants
• Usually restricted to the roots, lower stems, and lower branches of infected plants
• 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
Symptoms• Dead branches• Water-soaked
blossoms• Light brown/blackened
leaves• Discolored bark• Black “shepherd’s
crook” twigs• Dried fruit
Management• Pruning (Sterilize all tools after each cut)• Chemical Sprays
POWDERY MILDEW
• Lilacs, crab apples, phlox, monarda, roses, grapes, squash and cucumbers are all likely targets for powdery mildew
• Looks like powdery splotches of white or gray, on the leaves or stems of plants
• Different powdery mildew fungi infect different plants
Causes• Dampness• High humidity• Crowded plantings • Poor air circulation
Management• Avoid overhead watering• Remove and destroy all
infected plants• Prune overcrowded material
ROOT ROT Plants affected by root rot will start losing
their leaves, yellowing, drooping, and look like they’re dying
Affected plants will drink less water
Symptomso Appear overwatered
or droopyo Brown, slimy, smelly
rootso Plant leaves start
turning yellowo Plants drink much less
water than usual
Management• Keep growing area
clean• Add beneficial bacteria
to the water• Try to get as much
oxygen as possible dissolved in the water