Fungal Diseases

Apple Scab

Plants Affected

• Apple Trees

Symptoms

• Scabs on fruit, foliage damage mistaken for fireblight.

Controls

Cultural or Non-Chemical Controls:

• Rake up leaves and discard fruit.

Chemical Controls:

• Only used commercially in orchards.

Black Knot of Cherry

Plants Affected

• Schubert Chokecherry, Mayday (Prunus)

Symptoms

• Initially, new knots start out as branch swelling. 
• Large black ‘knots’ appear on branches the following year.

Controls

Cultural or Non-Chemical Controls:

• Prune out knots, clean pruners with bleach/alcohol after every cut.

Chemical Controls:

• None

Black Spot

Plants Affected

• Most varieties of roses.

Symptoms

• Round black spots form on leaves, stems and leaf stalks.
• Plants will most likely not be killed but can be severely stressed.

Controls

Cultural or Non-Chemical Control:

• Affected leaves or sections can be pruned out and discarded. 
  DO NOT COMPOST
• Good fall clean is essential so last years infected leaves don’t infect next years leaves.

Chemical Controls:

• Garden Sulphur

Botrytis Blight

Plants Affected

Symptoms

• Plants wilt when fungus enters stems at soil level:gray mold is sometimes seen.
• Disease can attack fruit or vegetables such as beans.
• Fungus on strawberry; mulch placed on ground around plant can reduce infection.

Controls

Cultural or Non-Chemical Controls:

• Ensure watering is done first thing in the morning.
• Keep plants pruned to promote proper air flow.
• Prune out and discard any badly affected portions to prevent further spread.

Chemical Controls:

• No chemicals available at this time.

Bronze Leaf Disease
of Aspen

Plants Affected

• Towering poplars
• Columnar Aspens (Trembling Aspens)

Symptoms

• First appear in mid summer leaves forming yellowish, orange brown or reddish brown discoloration near leaf margins.
• Discolored areas expand to cover the whole leaf except for the veins.
• As discoloration spreads, it turns bronze in color.
• Branch die back can occur as disease spreads

Controls

Cultural or Non-Chemical Controls:

• Remove infected branches and leaves, disinfect pruners after each cut.
• Good fall clean up.
• If any infected leaves or branches are on the tree in the fall remove them.

Chemical Controls :

• None disease is too new and is currently under study.

Clematis Wilt

Plants Affected

• Clematis

Symptoms

• Clematis wilt shows up as sections or the whole plant wilting and collapsing.

Controls

Cultural or Non-Chemical Controls :

• Cut down affected stems to ground level.
• Plant at proper depth for hybrid types, to give vines extra support; plant so top of rootball is 4"" deeper than soil surface.
  
• Plant in well drained soil fortified with lots of organic material.
  
• Keep plants properly staked etc to avoid damage to the stems; be careful when cultivating around plants.

Chemical Controls:

• No chemical controls are available.

Fairy Ring

Plants Affected

• Lawn

Symptoms

• Large circles form when fungus uses lawn as a food source. 
• Mushrooms may be seen—are fruiting spores of the fungus.  DO NOT confuse these with common mushrooms that appear after heavy rains.

Controls

Cultural or Non-Chemical Controls:

• Ensure a healthy lawn to fight off fungus — regular fertilizing and deep watering.
• Spike area with pitchfork, soak with soapy water—this ensures the lawn gets hydrated (fungus creates a thick band, making it difficult for water to reach lawn).
• Dig out ring (must dig 18” on either side of ring, and take caution not to get infected soil on lawn.

Chemical Controls:

• No fungicides available

Fireblight

Plants Affected

• Rose family - apple, crabapple, pear, mountain ash, cotoneaster

Symptoms

• Dramatic wilting at tips of new growth—shepherd’s crook.
• Scorched appearance of leaves.
• Clear, amber liquid may be seen oozing from plant.

Controls

Cultural or Non-Chemical Controls:

• Prune out affected branches 10” below infected area.  Disinfect tools in bleach between EVERY cut.

Chemical Controls:

• Copper or sulphur—spray on plant in mid-June—this acts as a preventative.  Sprays do not offer control once bacteria is present

Juniper
Hawthorn Rust

Plants Affected

• Juniper/Cedars, and Hawthorn, Crabapple, Mountain Ash

Symptoms

• Galls form on juniper/cedar leaves.
• After spring rains, galls ooze gelatinous ‘spore horns’.
• On alternate hosts, green-yellow spots show, later become orange-yellow surrounded by red bands.

Controls

Cultural or Non-Chemical Controls:

• Eliminate a host
• Prune out juniper galls in late winter/early spring before spore horns emerge.

Chemical Controls:

• No fungicides available at this time (alternate hosts would be sprayed.

Needle Cast

Plants Affected

• Spruce trees

Symptoms

• Mimics winter injury.
• Starts as light green to yellow spots, which turns to brown or red.
• Black spores will be seen on needles prior to drop (early spring).

Controls

Cultural or Non-Chemical Controls:

• Keep trees healthy and well watered.

Chemical Controls:

• None

Powdery Mildew

Plants Affected

• Many perennials and annuals, popular hosts include garden phlox, speedwell, salvia, begonias, impatiens.

Symptoms

• White powdery spots, yellowing leaves.
• Plants cannot manufacture as much food as they need - severe infestations will kill plants such as begonia.

Controls

Cultural or Non-Chemical Controls:

• Good circulation, full sun.
• Clean up debris in fall.

Chemical Controls:

• Sulphur, Neem Oil - apply in mid-June as a preventative; once mildew is present, fungicides are not effective.

Rust

Plants Affected

• Perennials, roses

Symptoms

• Reddish orange spots on leaves and stems.
• Wilting and defoliation follows.

Controls

Cultural or Non-Chemical Controls:

• Prune out, good fall cleanup.

Chemical Controls:

• Sulphur – important to apply prior to rust appearing (start applying in mid-June).  Fungicides are not highly effective once rust is seen.