Diseases in fruit crops

Production technology for fruit and plantation crops-
HT-244 (2+1)
PRESENTED BY:
RAKESH KUMAR PATTNAIK
Asst. Prof. Horticulture
MITS INSTITUTE OF PROFESSIONAL STUDIES
Dt- 15-07-20
LECTURE 18. DISEASES IN FRUIT CROP

Diseases of Mango
(Mengifera indica)

1. Powdery mildew:
Casual Organism: Oidium mangiferae
Symptoms:
 The infection starts from the inflorescence and spreads downwards covering
the floral axis, tender leaves and stem. Infected leaves become twisted, curled
and fall.
 Infected floral parts are severely damaged and drop off.
 If the fruits are set, they do not grow in size and may drop before attaining
pea size.
 The loss due to the disease may be as high as 70-80%.
Management:
 Two preventive sprays with wettable sulphur 0.3% before flowers open and after fruit set.
 Dusting twice or thrice with fine sulphur.
 Spraying with Karathane 0.1% before flowering and after fruit set.
Resistant varieties: Neelum, Zardalu, Banglora, Torapari-khurd and Janardhan pasand

1. Anthracnose:
Casual Organism: Colletotrichum gloeosporioides
Symptoms:
 The fungus produces leaf spots, blossom blight, wither tip, twigs
blight and fruit rot.
 On leaves circular, light yellow brown spots are produced initially
which soon enlarge with dark brown to black margins.
 On inflorescence stalks and flowers minute spots are produced which
increase in size and cause flower drop – the symptom hence is called
blossom blight.
 Sunken spots appear on fruits near the stem end as small brown areas
that enlarge rapidly and become black. Fruit pulp beneath the spots
become hard followed by cracking and decay at ripening.
Management:
 Avoid over-crowding in orchards.
 Spray carbendazim or thiophanate methyl (0.1%)
or Chlorothalonil (0.2%) at 14 days intervals
from fruit set until harvest.
 Before storage, treat the fruits with hot water (50-
55°C) for 15 minutes or dip in Benomyl solution
(500 ppm) or Thiobendazole (1000 ppm) for 5
minutes or expose them to ammonia and sulphur
dioxide gases.

1. Red rust:
Casual Organism: Cephaleuros virescens
Symptoms:
 The disease is characterized by red rusty spots on the leaves
and young twigs.
 The spots are initially circular, slightly elevated and later
coalesce and become irregular.
 The upper surface of the spot consists of numerous
unbranched sterile or fertile filaments of the pathogen which
project through the cuticle.
 Initially the spots are greenish-grey in colour but later on the
surface bears reddish-brown appearance because the algal
cells are impregnated with pigment which masks the normal
green chlorophyll.
Management:
 Avoid close plantations.
 Prune unproductive branches to improve
air circulation within the canopy of a
tree.
 Spray Bordeaux mixture 1% or copper
oxychloride 0.3%.

Diseases of Banana
(Musa spp.)

1. Yellow Sigatoka & Black Sigtoka:
Casual Organism: Mycosphaerella musicola (Yellow
Sigatoka)
Mycosphaerella fijiensis (Black Sigtoka)
Symptoms:
 Early symptoms appear on the lower leaves.
 Initially small reddish brown specks develop on leaves near
the tip or margin of lamina.
 Specks may also be produced near the midrib.
 Specks increase in size and turn in to spindle shaped spots
with reddish brown margin and gray centre surrounded by a
yellow halo.
 Spots formed near the midrib enlarge and extend towards
the margin of lamina.
 Spots coalesce and the entire spotted area appears dried.
Management:
 Planting banana in well drained soils.
 Growing moderately resistant cultivars like Karpura
Chakkerakeli.
 Prunning suckers periodically to avoid overcrowding in
the field.
 Applying recommended dose of potassium fertilizer.
 Spraying mancozeb or cholorothalonil 0.2% suspended
in mineral (paraffin) oil.

1. Panama wilt:
Casual Organism: Fusarium oxysporum f.sp. cubense
Symptoms:
 Fungus attacks roots and finds its way in to the pseudostem.
 symptoms usually appear on 3 to 5 months old plants,
although 2-3 months old plants are also killed under highly
favourable conditions.
 Affected leaves show progressive yellowing, break at the
petiole and hang down along the pseudostem.
 Longitudinal splitting of pseudostem is very common.
 Light yellow to dark brown discolouration of vascular
strands in pseudostem. Usually the discolouration appears
first in the outer or oldest leaf sheath and extends in to the
inner sheaths.
 The fungus grows and blocks the vascular system resulting
in wilting of the plant.
Management:
 Use of disease free suckers for planting.
 Planting In well drained soils.
 Application of lime (1-2 kg/pit) to the infected pits after
chopping of the plants parts.
 Dipping of suckers in carbendazim (0.1%) solution before
planting.
 Neem cake + Trichoderma viride should be applied in planting
pits.
 Growing resistant Cavendish varieties, viz., Basrai
(Vamanakeli or Dwarf cavendish),
 Poovan (Karpura chakkarakeli) etc.

1. Erwinia rhizome rot:
Casual Organism: Erwinia caratovora sub.sp. caratovora
Symptoms:
 Usually young plants are attacked. Under favourable
conditions even mature plants are infected.
 In newly planted young sprouting sucker the rhizome is
infected and infection progresses in to pseudostem .
 In established plants water-soaked spots develop on outer
leaf sheaths on base of pseudostem near the soil line.
 The spots turn brown and soft rotting of pseudostem tissue
and rhizomes takes place.
 Infected plants have scanty roots with dark brown lesions
and necrotic tip.
 Infection spreads to upper part of pseudostem and to
rhizomes.
Management:
 Avoid planting susceptible varieties during periods of high
rainfall or in water logged soils in problematic areas.
 Crop rotation with rice or sugarcane for three to four years.
 Ensure that only healthy suckers are planted.
 Dip the suckers in copper oxychloride (5g/lt) +
monochrotophos (2.5ml/l) solution
 Maintain proper soil aeration by intercultivation.
 Maintain optimum soil moisture by light and frequent
irrigation.
 Remove and destroy infected plants along with roots.

1. Banana Bunchy Top Virus (BBTV):
Casual Organism: Pentalonia nigronervosa
Symptoms:
 Primary symptoms of the disease are seen when infected
suckers are planted.
 Such infected suckers putforth narrow leaves, which are
chlorotic and exhibit mosaic symptoms.
 The affected leaves are brittle with their margins rolled
upwards.
 Characteristic symptom of bunchy top virus is the presence
of interrupted dark green streaks along the secondary veins
of the lamina or the midrib of the petiole.
Management:
 Use virus free planting materials.
 Remove and rouging of infected banana plants.
 Maintain clean, weed free field for early detection
of infested suckers
 The plants should be injected with 4 ml of
Fernoxone solution(50g in 400 ml of water)
 Spraying plants with phosphomidon 1ml /l or
Methyldemeton 2ml/ l or monocrotophos 1ml /l

1. Anthracnose:
Casual Organism: Gloeosporium musarum
Symptoms:
 At the initial stage, small, circular, black spots develop on
the affected fruits. Then these spots enlarge in size, turn to
brown colour.
 The skin of the fruit turns black and shrivels and becomes
covered with characteristic pink acervuli. Finally, the whole
finger is affected. Later the disease spreads and affects the
whole bunch.
 The disease results in premature ripening and shriveling of
the fruits which are covered with pink spore masses.
 Occurrence of black lesions on the pedicel causes withering
of the pedicel and dropping of the fingers from the hands.
Management:
 Spraying of Chlorothalonil (0.2%) and Bavistin (1 %)
four times at15 days interval is recommended.
 Minimizing bruising; proper sanitation of handling
and prompt cooling to 14°C are essential in
minimizing the disease in cold storage.
 Burn the infected materials
Keep the field free of weeds and provide good
drainage.

Diseases of Citrus
(Citrus spp.)

1. Gummosis:
Casual Organism: Phytophthora nicotianae var. parasitica, P.
palmivora, P. citrophthora
Symptoms:
 Disease starts as water-soaked patches on basal portions
of the stem near ground level
 Patches turn dark staining of bark brown
 Bark in such parts dries, shrinks and cracks and shreds
in lengthwise vertical strips.
 Later profuse exudation of gum from the bark of the
trunk.
 Infection extends to crown roots.
 Affected collar region is girdled and finally the infected
tree dies.
Management:
 Selection of proper site with adequate drainage
 Selection high budded grafts (30 to 45 cm or
above)
 Avoid injuries to crown roots or base of stem
during cultural operations
 Painting Bordeaux paste or with ZnSO4, CuSO4,
lime (5:1:4) to a height of about 60 cm
 above the ground level at least once a year.

1. Citrus canker:
Casual Organism: Xanthomonas axonopodis pv. Citri
Symptoms:
 Initially, disease appears as minute water soaked round,
yellow spots which enlarge slightly and turn brown, eruptive
and corky.
 These pustules are surrounded by a characteristic yellow
halo.
 Canker lesions on the fruit do not possess the yellow halo as
on leaves. Several lesions on fruit may coalesce to form
larger canker.
 Due to severe infections the there may be defoliation, and
twig and stem may show die-back symptoms.
Management:
 Select healthy seedlings and grafts for planting in new
areas
 Prune out and burn all canker infected twigs before
monsoon
 Periodical spraying of Streptocycline (1 g) + Copper
oxychloride (30 g) in 10 litres of
 water at fortnightly interval in nurseries and at fortnightly
interval in orchards during rainy season
 Use canker tolerant varieties like “Tenali selection” and
“Balaji”

1. Tristeza or quick decline:
Casual Organism: Citrus Tristeza Virus (CTV)
Symptoms:
 Disease affected tree leaves becomes chlorotic in
the early stages. Gradually the leaves drop and the
defoliated twigs show die-back.
 Diseased trees usually blossom heavily.
 Under the tree bark stem pitting can be observed.
 Trees with stem pitting are stunted and set less
fruits.
 The fruits are of smaller size and of poor quality
Management:
 Use certified budwood free of CTV to prevent primary
(vertical) spread of disease
 Remove all diseased trees as and when the disease is noticed.
Fresh plantings to be taken with virus free materials on
tolerant rootstocks.
 For Andhra Pradesh, Maharashtra and Karnataka, Rangapur
lime is recommended as a root stock resistant to Tristeza.
 Periodic sprays of insecticides like dimethoate or methyl S
demeton at 2 ml/l to reduce the secondary (horizontal) spread
of the disease in the orchard.

1. Greening or Huanglongbin:
Casual Organism: Liberobactor asiaticum (Phloem limited
bacteria)
Symptoms:
 Affected leaves show small circular green islands within
the chlorotic areas.
 Heavy leaf fall occurs with the onset of summer.
 Twig die-back may also occur.
 Affected areas of the fruits remain green and gives bitter
taste
 Affected fruits show reduction in size, loopsided growth
and oblique columella.
 Seeds are poorly developed, dark coloured and aborted.
Management:
 Select certified disease-free seedlings. Use
pathogen free bud wood for propagation
 Remove and destroy infected trees
 Control psyllids with insecticides like
dimethoate, or methyl s demeton
 500 ppm tetracycline spray, requires fortnightly
application.

1. Citrus scab:
Casual Organism: Elsinoe fawcetti
Symptoms:
 Initially small, semi-translucent dots like lesion develops on
leaves which become sharply defined pustular elevations.
 The opposite surface corresponding to the warty growth shows
a circular depression with a pink to red centre.
 On the fruit, lesions consist of corky projections which often
break into scab affecting larger areas on the fruits
Management:
 The diseased leaves, twigs and fruits should be collected and
destroyed.
 Spraying of Carbendazim 0.1% is quite effective

Diseases of Grapes

1. Powdery mildew
Casual Organism: Uncinula necator
Symptoms:
 Powdery growth mostly on the upper surface of the
leaves.
 Malformation and discolouration of affected leaves.
 Discolouration of stem to dark brown.
 Floral infection results in shedding of flowers and
poor fruit set.
 Early berry infection results in shedding of affected
berries.
 Powdery growth is visible on older berries and the
infection results in the Cracking of skin of the berries
Management:
 Prophylactic spray with B.M. 1% or Lime sulphur at
dormant stage delays development of disease by decreasing
initial inoculum
 Spray wettable sulphur @0.3% or Dinocap or Tridemorph
@0.1%
 Oxythioquinox (Morestan) @0.03% sprayed at 4 days
interval starting from last week of December to 1st week of
March
 Grow resistant varieties like Chholth Red, Chholth white,
Skibba Red, Skibba White

1. Downy mildew
Casual Organism: Plasmopara viticola
Symptoms:
 Irregular, yellowish, translucent sports on the upper
surface of the leaves.
 Correspondingly on the lower surface, white,
powdery growth on leaves.
 Affected leaves become, yellow, brown and gets
dried. Premature defoliation.
 Dwarfing of tender shoots. Brown, sunken lesions
on the stem.
 White growth of fungus on berries which
subsequently becomes leathery and shrivels.
 Later infection of berries results in soft rot
symptoms. No cracking of the skin of the berries.
Management:
The disease can be effectively managed by giving 3-5
prophylactic sprays with Bordeaux mixture 1% or
Fosetyl -Al (Aliette) 0.2% or curative spray with
Metalaxyl + Mancozeb (Ridomil MZ 72) 0.2% or
Azoxystrobin 0.1%

1. Anthracnose / Birds eye disease
Casual Organism: Elsinoe ampelina
Symptoms:
 The disease appears first as dark red spots on the berry.
 Later, these spots are circular, sunken, ashy- gray and in late
stages these spots are surrounded by a dark margin which
gives it the “bird’s-eye rot” appearance.
 The spots vary in size from 1/4 inch in diameter to about
half the fruit.
 The fungus also attacks shoots, tendrils, petioles, leaf veins,
and fruit stems.
 Numerous spots sometimes occur on the young shoots.
 These spots may unite and girdle the stem, causing death of
the tips.
 Spots on petioles and leaves cause them to curl or become
distorted.
Management:
 Removal of infected twigs
 Spraying Bordeaux mixture 1% or COC @ 0.25%
or carbendazim @ 0.1%.
 Varieties like Banglore blue, Golden Muscat,
Golden queen and Isabella are resistant

1. Alternaria leaf spot:
Casual Organism: Alternaria vitis
Symptoms:
 In the initial stage, minute, yellow spots appear on the upper
surface of leaves
 Later, spots enlarge and form brownish spots with
concentric rings in them
 Individual spots appear rarely in the middle of the leaves
 Appearance of patches of spots mostly along the margin of
leaves
 In severe cases of attack, leaves dry completely and
defoliation occurs
Management:
 Sanitation of the orchard
 Selection of disease-free planting
material
 Foliar spray of mancozeb@0.25%

1. Rust
Casual Organism: Phakopsora euvitis
Symptoms:
 Minute yellow coloured pustules are formed initially
on lower surface and later on upper surface
 These pustules turn in to orange powdery spores on
the underside of mature grapevine leaves
 Under severe infection, the entire leaf surface is
covered by sori leading to premature defoliation
Management:
 Field sanitation
 Destruction of alternate host
 Spray zineb@0.2% or dust
sulphur@25Kg/ha or Oxycarboxin 0.2% or
Triadimefon 0.1%

Diseases of Guava

Diseases of Papaya

Diseases of Pomegranate

Pineapple Diseases

Bacterial heart rot and fruit collapse Erwinia chrysanthemi
Symptoms
Water-soaked lesions on the white basal sections of leaves in the central whorl which may spread to all leaves in the
central whorl; midportions of leaves become olive green in color with a bloated appearance; infected fruits exude
juices and the shell becomes olive green; cavities form within the fruit
Cause
Bacterium
Comments
Disease is thought to be spread from the juices of infected fruits; bacteria in the juice can enter leaves through
wounds; ants acts as vectors for the bacteria
Management
Remove and destroy infected fruits; avoid the use of infected crowns for seed material to prevent spread of the
disease; planting to avoid flowering when adjacent field is fruiting can reduce disease development; use of miticides
and control of ants can significantly reduce disease incidence

Butt rot, Black rot & White leaf spot Chalara paradoxa
Symptoms
Soft black rot which begins at the area where the seed piece detaches from the mother plant; entire
seed piece may be rotted; black rot of fruit causes a soft, watery rot which darkens with time; small
brown, wet spots develop on leaves; leaf spots enlarge and turn gray-brown with light brown margins
Cause
Fungus
Comments
Fungus survives in soil and pineapple residue; infects plants through fresh wounds
Management
Seed material should be stored on mother plants during dry weather and with good air circulation;
freshly removed seed material should be dipped in an appropriate fungicide within 12 hours of
removal from the mother plant; avoiding bruising and wounding of fruit during harvest helps to
reduce black rot; harvested fruit should be dipped in an appropriate fungicide within 6-12 hours of
harvest to prevent disease development during shipping

Symptoms
Leaves turning red; tips of leaves become withered and turn
brown; plants can be easily removed from the soil
Cause
Virus
Comments
Virus is transmitted by mealybugs; ants protect mealybug
populations from predators and parasites and can allow
mealybugs populations to reach very damaging levels if left
uncontrolled
Management
Ants should be controlled with an appropriate insecticide
Mealybug wilt Pineapple wilt virus (PWV)

Phytophthora heart and root rot Phytophthora spp.
Symptoms
Young leaves failing to elongate and turning chlorotic; heart
leaves wilting and turning brown; terminal whorl can be easily
pulled from mother plant; water-soaked tissue at base of leaves;
foul smell; leaves may be turning red and yellow with necrotic
leaf margins and leaf tips; plants can easily be pulled out of the
ground; fruits color prematurely
Cause
Oomycete
Comments
Fungi can survive in soil and plant debris for many years
Management
Planting in raised beds helps to drain the soil and reduces
incidence of the disease; mulch from pineapple debris should be
avoided; pre-planting dips and foliar applications of Fosetyl Al
are very effective at controlling the disease

Diseases in fruit crops

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