Download Plant Health Management for Backyard Strawberries

Plant Health Management
for Backyard Strawberry
Plantings
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
Common Diseases on Fruit
Gray mold (Botrytis fruit rot)
Pathogen: Botrytis cinerea
Leather rot
Pathogen: Phytophthora cactorum
Gray mold
Symptoms:
gray, dusty-looking fungal growth on
ripening berries
Early (left) and late (right) stages of botrytis fruit rot on strawberry.
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
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.
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 windblown 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
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.
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.
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.
Common diseases on leaves
Leaf spot
Leaf scorch
Leaf blight
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.
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.
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.
Common Diseases Attacking
Roots
Verticillium wilt
Red stele
Black root rot
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.
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.
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.
diseased
healthy
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.
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.
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”.
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
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.
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”.
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.
The most effective method for
controlling most strawberry
diseases is the use of varieties
with good disease resistance.
Several strawberry varieties have resistance to many of the common
strawberry diseases. The following are some common varieties with
multiple disease resistance.
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
To get more information about plant
diseases visit the websites below.
http://www.ag.ohiostate.edu/~plantdoc/extension.php
http://www.ohioline.ag.ohio-state.edu