Transcript Plant Health Management for Backyard Strawberries Planting

Plant Health Management
for Backyard Stone Fruit
Plantings
(Peaches, Cherries, and
Plums)
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
Brown rot
Symptoms:
 Small, circular, light brown spots
expand rapidly on ripening fruit,
rotting the fruit within a day or two.
 Under wet conditions, ash-gray tufts
of fungus form on the surface of
infected fruit.
 Rotted fruit may fall from the tree or
remain attached as shriveled
mummies.
 Blossoms wilt, turn brown, and
persist into summer.
 Blossom infections can invade the
attached shoots or twigs and cause
cankers (areas of dead bark).
Cankers may enlarge and kill the
branch or twig.
Brown rot
Disease Development:
 affects all stone fruit
 caused by the fungus Monilinia fructicola.
 The fungus overwinters in the previous year's
diseased plant parts such as mummies, on the
tree or ground and in cankers on the twigs.
 In April, May and June, the fungus produces
millions of spores. These spores are spread by
splashing rain and by wind.
 A free film of water on leaves and fruit is required
for the spores to germinate and infection to
occur.
 Wounded fruit are most readily infected.
 Fruit rot symptoms become most evident as the
fruit start to mature.
Peach leaf curl and plum
pockets
Symptoms:
 In spring, developing leaves become
severely distorted (thickened and
puckered), and have a reddish or purple
cast.
 Later, as spores form on the leaf surface,
the leaves become powdery gray in color.
 Shortly after this, the leaves turn yellow or
brown and drop.
 Diseased twigs become swollen and
stunted, and may have a slight golden
cast. They usually produce curled leaves
at their tips.
 Diseased fruit have shiny, reddish, raised,
warty spots. They drop shortly after they
are infected.
Peach leaf curl and plum
pockets
Disease development:
 affects peaches and plums, but not cherry.
 caused by the fungus Taphrina deformans.
 The fungus survives the winter as spores (conidia)
on infected bark and buds.
 During cool, wet spring weather the conidia infect
new leaves as they emerge from the buds.
 Host plant tissues are susceptible for only a short
period. As the tissues mature they become resistant.
 The disease is not active later in the growing season.
 Rain (free water) is necessary for infection.
Peach scab
Symptoms:
 Small, round, olive-green spots generally
develop near the stem end or on the side of
the fruit exposed to the sun.
 Spots may merge to form large, irregular
blotches that turn velvety, dark olive-green
or black.
 Severely infected fruit may become
misshapen, or crack open, and drop
prematurely.
 Small, round, and yellowish-green to
yellowish-brown spots develop on the
underside of the leaf.
 Diseased leaf tissue may dry up and drop
out, leaving "shot-holes." If the season is
wet, scab-infected leaves usually drop
early.
Peach scab
Disease development:
 affects only peaches.
 caused by the fungus Cladosporium carpophilum.
 The fungus overwinters on bark and in twigs infected
the previous year.
 During spring and summer, large numbers of
microscopic spores (conidia) are formed on twig
lesions.
 The spores are spread by splashing rain or
windblown mist to developing fruit, twigs, and leaves.
 Spore germination and fungus growth is most rapid
at 65-75 degrees F.
 The fruit remain susceptible until harvest;
however,the disease is usually not observed until the
fruit are well grown.
Bacterial spot
Symptoms:
On leaves:
 Small, irregular to angular, deep
purple to rusty-brown or black
colored spots form on the leaves.
 In time, the centers dry and tear
away leaving ragged "shotholes."
 When several spots merge, the
leaf may appear scorched,
blighted, or ragged.
 Badly infected leaves may turn
yellow and drop early.
Bacterial spot
Symptoms:
On fruit:
 Small, round olive-brown to black
spots form on the fruit.
 They are usually sunken and
frequently surrounded by a watersoaked margin.
 On some varieties the spots may
exude a yellowish gum after rainy
periods.
 Skin cracking and pitting may
occur near the spots during fruit
enlargement.
Bacterial spot
Disease development:
 affects all stone fruit.
 caused by the bacterium Xanthomonas pruni.
 The bacteria overwinter in twigs that are infected late in
the season about the time leaves are shed.
 In the spring, bacteria ooze out from these diseased
plant parts onto the plant surface.
 The bacteria are then spread by windblown or
splashing rain and can result in new infections
throughout the growing season.
 Bacteria enter the tissues through natural openings
(stomata or lenticels) when surface moisture is present.
 Warm temperatures (70-85 degrees F) with light rains,
heavy dews, and windy weather are most conducive for
disease development and spread.
Cherry leaf spot
Symptoms:
 Small circular purple spots appear on the upper
surface of the leaf.
 Whitish-pink masses of sticky spores (conidia)
form within the spots on the undersides of
infected leaves during periods of damp weather.
 Later, the centers of the spots may dry up and
drop out, giving a "shot-hole" appearance.
 The most conspicuous symptom, especially on
sour cherries, is the golden yellowing of older
infected leaves before they drop off.
 Spots similar to those on the leaves may also
form on leaf petioles and fruit pedicels, causing
fruit to ripen unevenly. Spots usually do not
form on fruit.
Cherry leaf spot
Disease development
 affects only sweet and tart cherry
 caused by the fungus, Blumeriella jaapii .
 The fungus overwinters in dead leaves on the
ground.
 In spring, the fungus produce spores (ascospores)
during rainy periods for about six to eight weeks,
starting at petal fall.
 These spores are spread by wind or splashing rain
drops to healthy leaves and serve as primary
inoculum for the disease.
 The spores penetrate the leaf through stomata
(natural openings) on the underside of the leaf. The
small purple spots soon appear on the upper surface.
Cherry leaf spot
Disease development
 Masses of secondary or summer spores (conidia)
are produced in the spots on the underside of the
leaf.
 Conidia are spread to other leaves by splashing
raindrops and are capable of causing new
infections .
 Serious leaf spot damage (defoliation) usually
occurs in years with numerous rainy periods
throughout late spring and summer.
Powdery mildew
Symptoms:
On leaves and shoots:
 Spots first appear as circular,
white patches on leave surface.
 The white spots are growth of the
fungus mycelium and its spores.
 Lesions spread rapidly, eventually,
they may cover the entire leaf.
 Diseased leaves often fail to unfold normally, while those
of new shoots become narrow, distorted, blighted, and
stunted.
Powdery mildew
Symptoms:
On fruit
 The disease first appear as white circular
spots on young fruit.
 The spots enlarge and eventually, may
cover much of the fruit.
 Later, the skin of the fruit under the spot
turns pinkish, and the fungus and its
spores disappear.
 Eventually the skin becomes leathery or
hard, turns brown, and may crack.
Powdery mildew
Disease development:
 affects all stone fruit.
 Pathogens:






Podospaera clandestina…on cherry
Sphaerotheca pannosa…..on peach and other stone fruit.
The former overwinters as in fruiting bodies (cleistothecia) on the
barks and latter overwinters as mycelium dormant buds of
previously infected twigs..
In spring, the fungi initiate their growth and produce spores which
are carried by wind or rain to leaves, twigs and fruit.
Both leaves and fruit are susceptible to infection when young but
they become resistant as they mature.
Most infections occur at moderate temperatures and high
humidity.
Free water is not required.
The fungi produce secondary spores later in the growing season
cause secondary infections.
Management of fruit and leaf
diseases
Free water (wet conditions) is required for
most fungal pathogens (except Powdery
mildew) to infect plants. Any practice that
promotes faster drying of fruit and foliage
is beneficial for disease control.
Site selection
 Select a site with good air movement all-day
sun light, and good soil drainage.
 Do not plant trees in shaded areas.
Management of fruit and leaf
diseases
Canopy management
 Control timing and amount of nitrogen
fertilizer to prevent excessive growth.
 Prune out and destroy all dead or diseased
shoots and limbs while trees are dormant.
 Prune healthy growth to improve air
movement and sunlight penetration, to
minimize shading and decrease drying time
of leaves and fruit during the growing
season.
Management of fruit and leaf
diseases
Sanitation
 Remove all infected fruit and mummies as well as
blighted twigs from the tree.
 Rake out and dispose of fruit mummies and
leaves (cherry leaf spot) that have fallen to the
ground.
 These sanitation measures will reduce the
number of spores that can initiate these diseases.
Fungicides
 On susceptible varieties, fungicides may be
required to obtain an acceptable level of disease
control.
Management of fruit and leaf
diseases
Disease Resistance
 For most disease, resistance is not available.
 For bacterial spot and powdery mildew,
susceptible varieties should be avoided.
Susceptibility of common peach
cultivars to Bacterial spot
Resistant: Candor, Cresthaven, Earliglo, Encore,
Harbelle, Harbinger, Harbrite, Harken, Jerseydawn,
Norman, Pekin, Ranger, Redkist, Redskin
Tolerant: Biscoe, Earlirio, Garnet Beauty, Glohaven,
Jerseyqueen, Loring, Rio-Oso-Gem, Sentinel,
Springold, Summerglo, Sunqueen, Sunshine,
Surecrop, Topaz
Susceptible: Autumnglo, Blake, Harmony,
Jerseyland, Redcrest, Redhaven, Sweet Sue,
Suncrest, Sunhigh, Triogem, Tyler, Velvet,
Washington
Peach canker
Symptoms:
 In early spring, gummy drops of sap
first appear around wounded bark
 The inner bark begins to break down,
causing the cankered surface.
 During wet periods spores ooze out of
these cankered surfaces in tiny orange
or amber colored, curled strands.
 During the summer, healthy bark grows
over the edges of the narrow, oval
shaped cankers.
 Over a period of years, a series of dead
callus ridges form as the canker gets
larger.
 Eventually, the canker may completely
surround a branch. The portion of the
branch above the canker then dies.
Peach canker
Disease development
 affects all stone fruit, but most severe on peach.
 caused by the fungi, Cytospora leucostoma and
Cytospora cincta.
 These fungi are weak pathogens and generally do not
attack healthy, vigorous peach bark. Winter injury, insect
damage, and mechanical injury are common types of
wounds serving as entry points.
 The fungi survive the winter in cankers or in dead wood.
 During spring and summer, spores produced in the
cankers are spread by wind and rain to wounds on the
same or nearby trees.
 Infection and canker development depend on
temperature and the species of fungus involved.
Cytospora cincta is favored by lower temperatures than
Cytospora leucostoma.
Management of peach canker
Site selection:



Trees should be planted in sites with well drained soil
and good air circulation. This promotes faster drying.
Do not plant trees in shaded areas.
Do not plant new peach trees near established trees with
canker.
Pruning:


Prune young trees carefully to avoid weak, narrow-angled
crotches. Narrow-angled crotches are frequent sites of
breakage and winter injury.
Delay pruning until early spring. This promotes quick
healing and avoiding winter injury.
Sanitation:

Remove and destroy cankered limbs, branches and dead
wood while pruning. These limbs or branches serve as a
reservoir for the disease causing fungi.
Management of peach canker
Promote vigorous, healthy peach trees:
 Do not over-fertilize late in the season. Winter injury is more
common on these trees because winter hardening is
delayed.
 Trickle irrigation during dry period help to increase
resistance to the disease
Avoid mechanical and insect injury
 Maintain a good control program for other diseases and
insect pests, especially borers
Protect trees from winter injury
 White latex paint applied to the southwest side of trunks
and lower scaffold branches may help avoid cold injury
during winter.
Black knot
Symptoms:
 The fungus mainly affects twigs, branches, and
fruit spurs.
 On infected plant parts, abnormal growth of
bark and wood tissues produce small, lightbrown swellings.
 In late spring, the rapidly growing young knots
have a soft (pulpy) texture and become covered
with a velvety, olive-green growth of the fungus.
 In summer, the young knots turn darker and
elongate.
 In fall, they become hard, brittle, rough and
black.
 During the following growing season, the knots
enlarge and gradually encircle the twig or
branch.
 Smaller twigs usually die within a year after being infected. Larger
branches may live for several years before being girdled and killed by
the fungus.
Black knot
Disease development
 affects only plum and cherry.
 caused by the fungus, Apiosporina morbosa.
 The fungus overwinters in knots on twigs and
branches or in the infected wood.
 In spring, the fungus produces spores on the
surface of the knots.
 These spores are ejected into the air during rainy
periods and are blown for moderate distances by
wind currents.
Black knot
Disease development
 Only succulent green twigs of the current
season's growth are susceptible to infection.
 Only a few hours of rain are apparently required
for infection at temperatures above 55 degrees F.
 Knots may become visible by the late summer of
the year of infection but often are not noticed
until the following spring.
 The fungus continues to grow in infected wood
during spring and fall, causing the knots to
elongate several inches each year and eventually
girdle affected twigs and branches.
Management of Black knot

Site selection:




Sanitation:



Trees should be planted in sites with well drained soil and
good air circulation. This promotes faster drying.
Do not plant trees in shaded areas.
Avoid planting trees next to or downwind from an orchard
with a black knot problem.
infected twigs should be pruned out by making cuts 6
inches below the knot before bud break and destroyed by
burning or burying .
This sanitation measure will reduce the number of spores
that can initiate the disease.
Fungicides

On susceptible varieties, fungicides may be required to
obtain an acceptable level of disease control
Management of Black knot
 Use disease resistant plum varieties
 Most commercially grown plum varieties, including
Stanley and Damson, are highly susceptible to black
knot.
 Early Italian, Brodshaw, Fallenburg, Methley and Milton
are moderately susceptible.
 Shiro, Santa Rose, and Formosa are slightly susceptible
 President is apparently resistant to black knot.
 Japanese varieties of plums are generally less
susceptible than most American varieties.
Phytophthora root rot
Symptoms:
Above ground
 Affected trees exhibit poor terminal
growth, sparse and cholorotic foliage,
and progressive decline.
 Some trees exhibit early reddish
discoloration of leaves in late August or
early September.
 Eventually, infected trees usually die.
Below ground
 A diagnostic reddish-brown discoloration of
the inner bark and wood can be observed on
the crown or main roots of infected plants.
 A sharp line separates the reddish-brown
(diseased) and white (healthy) portion of the
crown.
Phytophthora root rot
Disease development:
 caused by several species of the fungus Phytophthora.
 The fungus overwinters and persists in soil for many years.
 The fungus requires extremely wet or saturated soils in
order to infect and cause significant damage; thus good
soil drainage is important for control.
 When soils are saturated, the fungus produces spores,
called zoospores. Zoospores use flagella to swim to
susceptible plant tissue where they cause infection.
 The longer the period or periods of soil saturation, the
greater the risk of infection.
 Some species may also be introduced to the orchard on
contaminated planting stock or through movement of
contaminated soil.
Management of Phytophthora
root rot
 Proper site selection
 Plant in well-drained soil.
 Plant on raised planting beds if soil does not have
excellent drainage.
 Select a site that does not have a previous history of
problems with the Phytophthora root rot.
 Use disease resistant rootstocks
 Mazzard cherry rootstocks are more resistant than
Mahaleb cherry rootstocks to some species of
Phytophthora.
 the effectiveness of resistant rootstocks is limited since
resistant rootstocks control some species of
Phytophthora but not others.
 On peach most currently available rootstocks are
susceptible.
Using Fungicides For Stone Fruit
Disease Control
 Fungicides are very important for disease
control in commercial stone fruit production,
and may be required in backyard stone fruit
plantings if highly susceptible varieties are
grown; however, the emphasis for disease
control in backyard plantings should be
placed on the use of disease resistance and
the various cultural practices previously
mentioned.
For backyard growers
that do require fungicides in
the disease management
program, fungicide
recommendations are
available for stone fruit in
Bulletin 780 “Controlling
Disease and insects In Home
Fruit Planting”.
Selected literature 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”
“Midwest Tree 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