Strawberry Diseases Leaf spots Grey mold Red stele/Red core Wilt Powdery mildew Alternaria spot Black root rot Anthracno...
Strawberry Diseases
- Leaf spots
- Grey mold
- Red stele/Red core
- Wilt
- Powdery mildew
- Alternaria spot
- Black root rot
- Anthracnose (black spot)
- Angular leaf spot
- Disease cycle:
- IPM for Strawberry
Leaf spots
Leaf spot
is one of the most common diseases of strawberries, occurring worldwide in most
cultivars.
Disease
symptoms:
- Initially, small, deep purple,
round to irregularly shaped spots appear on the upper leaf surface
- These enlarge to between 3–6 mm
in diameter. They retain a dark red margin, but the centers turn brown,
then grey and finally white. Spots may join and kill the leaf
- The fungi also attacks the
petioles, stolons, fruit stalks and fruit as shallow black spots.
Survival
and spread:
- infected leaves from current
and previous strawberry crops
- Splashing water from rain and
overhead irrigation
Favourable
conditions:
- Extended wet periods,
particularly in late spring
Grey mold
This
disease occurs on a wide range of flowers, vegetables and fruit, including
strawberries.
Disease
symptoms:
- The fungi will attack flowers,
fr
uit, petioles, leaves and
stems - Flowers and fruit stalks
infected during flowering die rapidly. Green and ripe fruit develop brown
rot
- This spreads over the whole
fruit, which becomes covered with masses of dry, greyish spores
- The rot may start on any
portion of the fruit, but is found most frequently on the calyx end or on
the sides of fruit touching other rotten fruit
Survival
and spread:
- The fungi over-winters on plant
debris and infects flower parts, after which it either rots the fruit or
remains inactive until the fruit ripens further. Spores, which are
produced continuously throughout the fruiting season, germinate to infect
plants
- By wind and splashing water
from rain or overhead irrigation
Favourable
conditions:
- Low temperature, high humidity
and frequent rain
Red stele/Red core
Disease symptoms:
- Red stele affected plants
become stunted and wilt in dry weather.
- Older leaves turn yellow or red
particularly along the margin.
- The symptom that helps to
identify red stele is the brick red discoloration in the center (stele) of
live white roots.
- The red color may extend the
length of the root, or it may show up for only a short distance above the
dead root tip.
- This symptom is obvious only
during winter and spring.
- The discoloration does not
extend into the crown of the plant.
- Infected plants usually die by
June or July.
- Growth of the plants will slow
down and they will become dull bluish green. In spring the plants will
convalesce somewhat.
- An affected plant will form no
or only few flowers.
- The small fruits will dry out.
The root-hair of the roots is lacking.
- When cutting the main roots, it
will appear that the central cylinder has discolored red
Survival and spread:
- Can be introduced with planting
material or from a reserve in the soil from trash from previous crops
Favourable conditions:
- Found in a wide range of
climates. The disease prefers poorly drained soils, high temperatures and
plants under moisture stress
Wilt
This
disease occurs through the temperate zones of the world. It affects a wide
range of crops like tomato, potato and cotton. Most strawberry varieties are
susceptible
Disease symptoms:
- Plants carrying a large crop
will suddenly wilt, usually on a hot day in late spring or summer.
- Some plants do not recov
er, and die within a week. - In surviving plants, older
leaves take on a scorched look while younger leaves remain pale in colour and
turgid until they also die off.
- Fruit on affected plants do not
mature, remain small and have paler appearance.
Survival and spread:
- Soils in which susceptible
crops have been grown
- The pathogen can survive in
moist soil for many years
- By water, trash from
susceptible crops, weeds, root contact between plants, soil and farm
machinery
Favourable conditions:
- A period of stress such as
sudden increase in temperature, dry conditions or heavy crop load on
plants
Powdery mildew
The
disease affects all cultivated strawberries worldwide. No variety is resistant,
but each differs in susceptibility.
Disease symptoms:
- An early symptom of the disease
is upward curling of the leaf margins.
- This is followed by irregular,
purple blotching on the upper leaf surfaces, often along major veins. The
leaves feel brittle.
- This disease does not produce
the masses of greyish white spores typical of powdery mildew on other
crops.
- Powdery mildew can attack fruit
at any stage.
- Dull immature and mature
berries with prominent planting materials
Survival and spread:
- Trash from previous and current
strawberry crops.
- Wind
Favourable conditions:
- Warm, humid conditions
Alternaria spot
Disease symptoms:
- Lesions or "spots"
are more numerous on upper leaf surfaces and appear circular to irregular
in shape.
- These lesions often have
definite reddish-purple to rusty-brown borders that surround a necrotic
area.
- Lesion size and appearance
often are influenced by the host variety and the ambient temperature.
- The leaf spots sometimes cause
severe problems, often depending on the variety planted.
- Susceptible varieties can be
defoliated partly or completely by late summer. In years that are
particularly favorable for disease development, they can be severely
weakened.
Survival and spread:
- The fungi overwinter on
infected plants, plant debris, and weed hosts.
- In the spring, spores are
produced and are discharged by splashing rain into air currents. They then
land on and infect new leaves.
Favourable condition:
- It is favoured by warm wet
weather
Black root rot
Disease symptoms
- Normal strawberry roots are
white, but naturally turn dark on the surface with age.
- The root system of a plant
affected by black root rot is smaller with black lesions or with the roots
completely black.
- Such plants become stunted and
produce few berries and runners.
Survival and spread:
- Black spot is spread from
infected plants and fruit by rain splash, overhead irrigation and on the
hands of fruit pickers.
Favourable conditions:
- It is favoured by warm, humid
and wet conditions.
Anthracnose (black spot)
Disease symptoms: Leaf spot
- Round black or light gray
lesions on leaves.
- Numerous spots may develop but
leaves do not die.
Runners and petioles
- Dark brown or black sunken,
circular lesions on stems, petioles and runners
- Plants may be stunted and
yellow
- Plants may wilt and collapse
- Internal tissues discolored red
Crown rot
- Youngest plant leaves wilt
during water stress in early afternoon and recover in the evening
- Wilting progresses to entire
plant
- Plant death
- Reddish-brown rot or streak
visible when crown is cut lengthways.
Bud rot
- Damp, firm dark brown to black
rot on buds.
- Plants with single buds may
die.
- Plants with multiple crown may
wilt as disease progresses.
Flower blight
- Dark lesion extending down
pedicel which girdles the stem and kills the flower; flowers dry out and
die.
- Infection after pollination may
result in small, hard, deformed fruit.
Fruit rot
- Light brown water-soaked spots
on ripening fruit which develop into firm dark brown or black round
lesions
Survival and spread:
- This is a major disease of
strawberries, affecting most parts of the plant.
- It can cause serious losses
throughout the season.
- Plants that are planted in
infected soil become infected by splashing water and soil
- Fungus survives in soil for up
to 9 months.
Favourable conditions:
- It is favoured by warm wet
weather
Angular leaf spot
Disease symptoms:
- Very small water-soaked lesions
on lower surfaces of leaves which enlarge to form dark green or translucent
angular spots which ooze bacteria.
- Lesions may coalesce to form
reddish spots with a chlorotic halo
Survival and spread:
- Bacterium survives in crop
debris and overwintering plants can survive for long periods on plant
debris but cannot live free in soil.
- Bacteria can be spread by
splashing water.
Favourable conditions:
- Spring season is responsible
for the development of diseases.
Disease cycle:
Leaf
spot:
Grey
mould
Red
stele/Red core
Wilt
Powdery
mildew
IPM for Strawberry
To know
the IPM practices for Strawberry, click here.
Source: NIPHM; Directorate of Plant
Protection, Quarantine Storage
35 ratings and
Strawberry Insect
Pests
Leaf roller
Biology:
The adult
garden tortrix is a buff-brown moth that is about 1/4 inch (6 mm) long. Each of
the forewings is marked with a dark brown diagonal stripe and a marginal spot
producing a chevron pattern when at rest. A faint whitish line borders the
anterior edge of the brown stripe. This character and the overall lighter color
distinguish adult garden tortrix from orange tortrix. The slender caterpillars
of the garden tortrix are nearly 1/2 inch (12 mm) long when mature.
Caterpillars have light brown to green bodies and light brown heads. The head
has a small, distinct dark brown spot on each side. Larvae and pupae overwinter
in debris around the base of the plant.
Damage symptoms:
- It ties one or more strawberry
leaves together with white webbing to create shelters.
- Larvae can also create shelters
by binding leaves or the sepals of the calyx to fruit and may feed from
these sheltered areas on the surface or internal tissues of fruit.
White grub
Biology:
- Egg - Eggs hatch in 3 to 4 weeks. A dull pearly white
when first deposited, the oval to spherical egg turns dark just before
hatching. It may be 1.5 to 3 mm in diameter. Small masses of 15 to 20 eggs
occur in cells in the soil.
- Larva - Newly hatched grubs feed on plant roots throughout
the summer and complete 1/3 of their development before fall. These grubs
burrow below the frostline (to a depth of 1.5 meters) and hibernate. The
young grub is creamy white and about 5 mm long. The grub is about 26 mm
long, and the mature grub about 30 mm long. The C-shaped grub has a
distinct brown head; a shiny, smooth body; and three pairs of legs just
behind the head. Two rows of hairs on the underside of the last segment
distinguish May beetle grubs from similar grubs.
- Pupa - The grubs become fully grown by late spring of the
third year. At this time, they dig cells in the soil and pupate.
Approximately the same size as the adult, the pupa may be creamy white,
pale yellow, or dark brown. Pupae become adults by late summer but the
beetles do not leave the ground.
- Adult - Known as May beetles, the shiny reddish-brown
to black adults are 19 to 26 mm long. The adult attack strawberry during
spring. New May beetles overwinter in their earthen cells and emerge the
following spring to feed and mate.
White
grubs complete one generation every 3 years.
Damage symptoms:
- Plants affected by this insect
can show early signs of wilting, remain small, weak, and both yield and
fruit quality is affected.
- Soil disclosure at the bottom,
the larve is seen gathering on the roots.
- If large numbers of insects are
present, plants may die
Thrips
Biology:
- Egg: Eggs are laid in plant tissue, both in flower
bottoms and in leaves.
- Larva: Subsequently, the larvae develop in stages. This
development also occurs both in the leaves and in the flower bottoms of
the plant.
- Pupa: In the pre-pupating stage the greater part of the
thrips drops on the ground and looks for some dirt or creep under plastic
to pupate. When the pupae have come out, the adult thrips will move to the
plants again and after a number of days they will start laying eggs.
- Adult: Thrips wings are fringed with setae, small hairs.
They are also known to be specially active in flying during hot and close
weather. The best way to find thrips is by removing petals and the stamina
of the flowers.
Damage symptoms:
- Both nymphs and adult thrips
can injure the plant by rasping the
plant bud,
flower, leaf tissues and then sucking the exuding sap. - Thrips feeding on strawberry
blossoms cause the stigmas and anthers to turn brown and wither
prematurely, but not before fertilization has occurred.
- With high populations, the
surface of the berry may become cracked and discolored.
- Fruit damage includes surface russeting
around planting materials from late green to ripe fruit. The fruit can
take on a seedy bronze-like appearance.
- Larvae and adult thrips will be
sucking on the fruits.
- Brown scaly sucking patches
round the planting materials planting materials planting materials.
Red spider mite
Biology:
The
two-spotted spider mite can live on strawberries, but also on numerous
different crops. It is also present in different weeds, such as Black
Nightshade, small stinging nettle and gallant soldier. The adult females
overwinter in sheltered places in the crops. In spring they become active.
Recognizing them, not the color is decisive but rather the two black spots on
their body. Life stages comprises of egg, larvae, protonymph, deutonymph and
adult. Life cycle will be completing in around 5-20 days depending on
temperature.
- Egg: From mid April eggs are laid on the underside of
the leaves. Female lays 100 eggs in around 10 days, round clear initially
and turn whitish as it matures
- Nymph: The nymph vary in color, from yellow to light and
dark green. Sometimes they are even orange in color.
- Adults: males are wedge shaped 0.33mm and females are
oval 0.4-0.5 mm, single dark spot on either side of body and generally
yellow or greenish in color.
Life
Cycle:
Damage
symptoms:
- Spider mites rasp away leaf surfaces
to feed on plant sap
- The first signs of damage are
speckling and mottling on the surface of leaves.
- In heavy infestations, leaves
turn purple, with white webbing between leaves.
- Plants that sustain
infestations of greater than 75 mites per leaflet may become severely
weakened and appear stunted, dry, and red in coloration.
- Severely damaged leaves die and
drop
Root knot nematode
Biology:
- Most species of plant parasitic
nematodes have a relatively simple life cycle consisting of the egg, four
larval stages and the adult male and female. They are microscopic in size.
- Development of the first stage
larvae occurs within the egg where the first moult occurs. Second stage
larvae hatch from eggs to find and infect plant roots or in some cases
foliar tissues.
- Under suitable environmental
conditions, the eggs hatch and new larvae emerge to complete the life
cycle within 4 to 8 weeks depending on temperature.
- Nematode development is
generally most rapid within an optimal soil temperature range of 70 to
80°F.
Life
cycle:
Life
stages are microscopic in size
Damage
symptoms:
- Infected plants in patches in
the orchard
- Formation of galls on host root
system is the primary symptom
- Roots branch profusely starting
from the gall tissue causing a ‘beard root’ symptom
- Infected roots become knobby
and knotty
- In severely infected plants the
root system is reduced and the rootlets are almost completely absent. The
roots are seriously hampered in their function of uptake and transport of
water and nutrients
- Plants wilt during the hot part
of day, especially under dry conditions and are often stunted
- Seedlings infected in nursery
do not normally survive transplanting and those surviving have reduced
flowering and fruit production
- Nematode infection predisposes
plants to fungal and bacterial root pathogens
Survival and spread:
- Primary: Egg masses survive in infected plant debris and soil or
collateral and other hosts like Solonaceous, Malvaceous and Leguminaceous
plants act as sources of inoculum
- Secondary: Autonomous second stage juveniles that may also be
water dispersed
Favourable conditions:
- Loamy light soils
IPM for Strawberry
To know
the IPM practices for Strawberry, click here.
Source: NIPHM; Directorate of Plant Protection, Quarantine
& Storage
32 ratings
Strawberry Pests
Pests of National Significance
Insect and mite pests
- Red spider mite: Tetranychus urticae (Koch)
(Trombidiformes: Tetranychidae)
- Leaf roller: Ancylis comptana Frölich (Lepidoptera:
Totricidae)
- Thrips: Scirtothrips dorsalis Hood (Thysanoptera:
Thripidae)
- White grubs: Phyllophaga spp. (Harris)
(Coleoptera: Scarabaeidae)
- Fruitfly
Diseases
- Leaf spots: Mycosphaerella fragariae (Lindau)
- Grey mold: Botrytis cinerea (De Bary)
- Wilt: Verticillium albo-atrum (Wollenw)
- Powdery mildew: Sphaerotheca macularis (Braun and
Takam)
- Alternaria spot: Alternaria sp
- Red stele/Red core: Phytophthora fragariae Hickman
- Black root rot: Complex disease (fungi
nematodes)
- Anthracnose (black spot): Colletotrichum fragariae A.N.
Brooks, Colletotrichum gloeosporoides (Penz.) Penz. .
Sacc, Colletotrichum acutatum J.H. Simmonds
- Angular leaf spot: Xanthomonas fragariae Kennedy King
Weeds
Grass weeds:
- Burmuda grass: Cynodon dactylon (L.) Pers. (Poaceae)
- Goose grass: Eleusine indica (L.) Gaertn.
(Poaceae)
- Signal grass: Brachiaria ramosa (L.) Stapf
(Poaceae)
- Crab grass: Digitaria spp. (Poaceae)
- Couch grass: Elymus repens (L.) Gould (Poaceae)
Broadleaf weeds:
- Sorrel: Oxalis latifolia Kunth (Oxalidaceae)
- Burclover: Medicago denticulata (Fabaceae)
- Carpet weed: Trianthema portulacastrum L.
(Aizoaceae)
- Corn spray: Spergula arvensis L.
(Caryophyllaceae)
- Mock strawberry: Duchesnea indica (Andr). Focke
(Rosaceae)
- Lambs quarter: Chenopodium album L. (Chenopodiaceae)
- Sweet yellow clover: Melilotus indica (L.) All. (Fabaceae)
- Toothed Dock: Rumex dentatus L. (Polygonaceae)
- Little mallow: Malwa parviflora L. (Malvaceae)
Sedges
- Yellow nut sedge: Cyperus esculentus L.
(Cyperaceae)
- Purple nut sedge: Cyperus rotundus L.
(Cyperaceae)
Rodents
- Soft Furred Orchard Rat: Melardia meltada
Pest of Regional Significance
Insect pests
- Cutworms: Agrotis ipsilon Hufnagel (Lepidoptera: Noctuidae)
- Hairy caterpillars: Euproctis chrysorrhoea (Linnaeus)
(Lepidoptera: Lymantriidae)
- Aphids: Chaetosiphon fragaefolii Cockerell; Aphis Forbesi
Weed (Homoptera: Aphididae)
- Root louse: Aphis Forbesi (Weed) (Homoptera:
Aphididae)
- Gram pod borer
- Tobocco caterpillar
- Lygus sp.
Diseases
- Anthracnose: Colletotrichum sp (Brooks)
- Wilt: Fusarium spp
- Post harvest rot: Rhizopus nigricans (Ehrenberg)
Nematodes
- Leaf nematodes/Strawberry crimp
nematode: Aphelenchoides
fragariae (Ritzema Bos and
Christie)
- Stem nematodes: Ditylenchus dipsaci (Kuhn)
- Root knot nematodes: Meloidogyne spp (Goldie)
IPM for Strawberry
To know
the IPM practices for Strawberry, click here.
Source: NIPHM;
Directorate of Plant
Protection, Quarantie Storage
28 ratings
Strawberry Beneficial
Insects
Natural
Enemies of Strawberry
Insect Pests
Parasitoid
Predators
IPM for Strawberry
To know
the IPM practices for Strawberry, click here.
Source: NIPHM ;
Directorate of Plant
Protection, Quarantine Storage
28 ratings
Strawberry Crop
stage-wise IPM
|
Management |
Activity |
Pre planting
|
|
|
Common cultural practices:
|
|
|
Nutrients |
|
|
Weeds |
|
|
Soil borne pathogens, nematodes,
resting stages of insects |
Biological control:
|
Planting
|
|
|
Nutrients |
|
|
Weeds |
|
|
Soil borne pathogens, nematodes,
resting stages of insects |
Cultural control:
|
Bud and pre-bloom
|
|
|
Nutrients |
|
|
Weeds |
|
|
Red Spider Mite |
Cultural control:
Biological control:
|
|
Alternaria Leaf spot |
Cultural control:
|
|
Powdery Mildew |
Mechanical control:
|
|
Leaf Spot |
Mechanical control:
|
|
Red stele |
Cultural control:
|
|
Black root rot |
Cultural control:
|
|
Anthracnose (black spot) |
Cultural control:
|
|
Angular leaf spot |
Cultural control:
|
Bloom
|
|
|
Nutrients |
|
|
Weeds |
|
|
Red spider mite |
|
|
Leaf Roller |
Cultural control:
|
|
Root Louse |
Cultural control:
Biological control:
|
|
Aphids |
Cultural control:
Biological control:
|
|
Cut worms |
Cultural control:
Mechanical control:
|
|
Wilt |
Cultural control:
|
|
Alternaria leaf Spot |
Cultural control:
|
|
Powdery Mildew Leaf Spot Red stele
Black root rot Anthracnose (black spot) Angular leaf spot |
|
|
Petal fall/ fruit stage |
|
|
Red Spider Mite |
|
|
Leaf Roller |
|
|
Wilt |
Cultural control:
|
|
Alternaria leaf spot |
Cultural control:
|
|
Powdery Mildew Leaf Spot Red stele
Black root rot Anthracnose (black spot) Angular leaf spot |
|
Fruit development stage
|
|
|
Weed |
|
|
Red spider Mite |
|
|
Vine weevil |
|
|
Leaf roller |
|
|
Root louse |
|
|
Thrips |
Cultural control:
|
|
White grubs |
Mechanical control:
|
|
Wilt |
|
|
Powdery mildew, Leaf Spot Red stele
Black root rot Anthracnose (black spot) Angular leaf spot |
|
|
Alternaria leaf spot |
|
|
Gray mold |
Cultural control:
|
|
Rodent |
Cultural control:
|
|
White buds |
Cultural control:
|
Post-harvest
|
|
|
White grubs |
Cultural control:
Biological control:
|
|
Root louse |
Cultural control:
Biological control:
|
|
Nematode |
Cultural control:
|
|
Wilt |
|
Source:NIPHM Directorate
of Plant Protection, Quarantine & Storage
COMMENTS