Plant Health Management for Backyard Strawberry Plantings

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Plant Health Management for Backyard Strawberry
Plantings
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• Prepared by
• Mike Ellis Professor and
  Extension Specialist
  and
  Omer Erincik
  Graduate Research Assistant
• Department of Plant Pathology
  
  The Ohio State University
  OARDC/OSUE
  Wooster, OH, 44691

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Common Diseases on Fruit

• Gray mold (Botrytis fruit rot)

Leather rot
Pathogen Botrytis cinerea
Pathogen Phytophthora cactorum
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Gray mold

• Symptoms
• gray, dusty-looking fungal growth on ripening
  berries

Early (left) and late (right) stages of botrytis
fruit rot on strawberry.
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Gray mold

• Disease Development
• Most infections occur during bloom.
• The fungus can infect petals, flower stalks,
  fruit caps, and fruit.
• The disease is favored by wet conditions, such as
  rain, dew, or sprinkler irrigation.
• The disease is generally most severe
• in shaded areas where humidity is higher and air
  movement is poor
• on berries touching the soil

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Leather rot

• Symptoms
• On green fruit, brown, firm spots develop. The
  entire berry may be discolored (brown).
• On ripe fruit, light to dark purple or brown
  areas develop. These areas are generally dull in
  color.

• Infected fruit have a distinctive bitter taste
  and unpleasant odor.

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Leather rot

• Disease Development
• The fungus can infect berries at any stage of
  development.
• Disease can develop very quickly during wet
  conditions.
• a wet period of two hours is sufficient for
  infection.
• Fungus spores are spread by splashing or
  wind-blown water from rain or overhead
  irrigation.
• the disease is most severe
• in poorly drained areas
• in places where berries are in contact with the
  soil

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Management of fruit rot diseases
Free water (wet conditions) is required for most
fungal pathogens to infect fruit. Any practice
that promotes faster drying of fruit and foliage
is beneficial for disease control.
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Management of fruit rot diseases

• Site selection
• Select a site with good air movement and sun
  exposure (promote faster drying).
• Canopy control
• Control timing and amount of nitrogen fertilizer
  to prevent excessive growth.
• Control weeds
• weeds decrease air circulation.
• controlling weeds promotes faster drying of fruit
  and foliage.
• Mulch
• Use a layer of straw mulch to create a barrier
  between fruit and soil.

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Management of fruit rot diseases

• Irrigation
• Irrigate early in the day, so plants dry faster.
• Handling
• Pick fruit carefully, avoid bruising
• Process and or refrigerate fruit immediately
  after harvest.
• Renovation
• Remove old leaves and diseased plant parts after
  harvest.

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Common diseases on leaves

• Leaf spot

Leaf scorch
Leaf blight
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Symptoms of leaf diseases

• Leaf spot
• Small reddish purple spots develop with tan to
  grayish white centers surrounded by a purple
  margin.
• Leaf scorch
• Round to angular or irregular dark purple spots
  or blotches developed.
• Eventually the entire leaf may turn red.
• Leaf blight
• Spots are initially reddish-purple,
• Later they develop a darker brown or
  reddish-brown center surrounded with a purple
  border.

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Strawberry leaf diseases

• Disease Development
• Leaf spot
• Pathogen Mycosphaerella fragariae
• Infection may occur throughout the growing season.

• Leaf scorch
• Pathogen Diplocarpon earliana
• Infection may occur throughout the growing season.

• Leaf blight
• Pathogen Phomopsis obscurans
• Disease is found most commonly on plants after
  harvest.

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Management of strawberry leaf diseases

• Use disease free planting stock
• Use resistant varieties
• Proper site selection
• Choose a site with good air circulation and sun
  exposure (promotes faster drying).
• Weed control
• Weeds decrease air circulation.
• Controlling weeds reduces drying time of the
  plants.
• Remove old foliage just after harvest
  (renovation)
• helps to reduce pathogen populations.

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Common Diseases Attacking Roots

• Verticillium wilt

Red stele
Black root rot
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Verticillium wilt

• Symptoms
• Older leaves turn brown or reddish yellow at the
  edges, then turn entirely brown and collapse.
• Roots have areas of dark brown decay.

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Verticillium wilt

• Disease Development
• Caused by the soil borne fungus
  Verticillium albo-atrum
• The fungus can be introduced into uninfested soil
  on seed, tools, garden machinery and roots of
  transplants.
• The fungus can survive in soil for many years.
• Favored by cool, overcast weather interspersed
  with warm days.

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Red stele

• Symptoms
• Many roots may have a rattail appearance, with
  few or no lateral roots.
• When infected roots are split, the center core
  (stele) is brownish or red.

healthy
diseased
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Red stele

• Disease development
• caused by a soil borne fungus,
• Phytophthora fragariae
• favored by high soil moisture (saturated soil)
  and cool temperature.
• most destructive in heavy clay soils that are
  saturated with water during cool weather.

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Black root rot

• Symptoms
• Plants are stunded
• Roots show areas of brown to black discoloration.
• Eventually, all or part of the main root system
  is black and dead.

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Black root rot

• Disease Development
• The disease has been associated with several
  factors, and is not clearly understood.
• One or more of the following factors has been
  associated with the disease
• soil fungi, nematodes, winter injury, fertilizer
  burn, soil compaction, herbicide damage, drought
  stress, excessive water, improper soil pH.
• Probably not caused by any single factor.
  Considered to be a Disease Complex.

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Management of root diseases

• Use healthy planting stock
• Use resistant varieties
• Proper site selection
• Plant in well-drained soil
• Select a site that does not have a previous
  history of problems with any of the root
  diseases.
• Rotation
• Do not replant strawberries where disease has
  been a problem for at least 2 years.
• Control weeds

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Using Fungicides For Strawberry Disease Control

• Fungicides can be important in commercial
  strawberry plantings however, fungicides are
  generally not recommended for backyard
  strawberry production.
• Effective fungicides registered for use on
  strawberry are usually very difficult or
  impossible for backyard growers to obtain.
• If not used properly, they are generally not
  effective.

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• For backyard growers that do wish to use
  fungicides in the disease management program,
  fungicide recommendations are available in
  Bulletin 780 Controlling Disease and insects In
  Home Fruit Planting.

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Emphasis for disease control in backyard
strawberry plantings should be placed on

• Use of the various cultural practices for disease
  control mentioned previously.
• Use of disease resistant varieties.

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• The most effective method for controlling most
  strawberry diseases is the use of varieties with
  good disease resistance.

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Several strawberry varieties have resistance to
many of the common strawberry diseases. The
following are some common varieties with multiple
disease resistance.
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Selected literatures for backyard fruit
production and plant health management

• Bulletin 591. Growing and Using Fruit at Home
• Bulletin 780. Controlling Diseases and Insects
  in Home Fruit Planting
• Bulletin 861. Midwest Small Fruit Pest
  Management Handbook.
• These can be obtained through your county
  extension agent or the Extension Publications
  Office, The Ohio State University, 385 Kottman
  Hall, 2021 Coffey Road, Columbus, Ohio, 43210-1044

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• To get more information about plant diseases
  visit the websites below.
• http//www.ag.ohio-
• state.edu/plantdoc/extension.php
• http//www.ohioline.ag.ohio-state.edu