This document summarizes several common diseases that affect musk melon crops. It describes over 20 different diseases caused by fungi, bacteria, viruses, nematodes, and other pathogens. Each disease entry provides the symptoms caused on the plant and identifies the causal organism. The diseases discussed threaten musk melon yields by causing leaf spots and blights, wilting, stem rots, fruit rots, and in some cases killing the entire plant. Proper identification of diseases is important for implementing effective management strategies.

2. Musk melon Diseases
A
Lecture To ToT trainees ( FFS)
By
Mr. Allah Dad Khan
Provincial Coordinator IPM KPK
MINFAL Pakistan

4. Root knot nematode
Meloidogyne spp.
Symptoms
 Galls on roots which can be
up to 3.3 cm (1 in) in diameter
but are usually smaller;
reduction in plant vigor;
yellowing plants which wilt in
hot weather
 Cause
 Nematode

5. Southern blight (Stem and fruit
rot)
Sclerotium rolfsii
Symptoms
 Sudden wilting of leaves;
yellowing foliage; browning
stem above and below soil;
browning branches; stem
may be covered with fan-like
mycelial mat
 Cause
 Fungus

6. Fusarium wilt
Fusarium oxysporum
Symptoms
 Yellowing and wilting of runners;
lesions on the runner extend from
crown to tips; lesions on roots and
stems; internal red to brown
discoloration
 Cause
 Fungus
 Comments
 Disease emergence favored by warm,
wet soil
 Management
 Plant in well draining soils and avoid
waterlogging; plant fungicide treated
seed; rotate crops on 4 year rotation

7. Gummy stem blight
Didymella bryoniae
Symptoms
 Circular brown or tan spots of
various sizes on leaves; leaves
covered with lesions; stems
splitting and forming cankers;
wounds exude a brown, gummy
substance; wilting vines; death
of stems; small water-soaked
lesions on fruit which enlarge
and exude gummy subatnace;
black fruiting bodies often
present in lesions
 Cause
 Fungus

8. Anthracnose (Leaf spot, Fruit rot)
Colletotrichum orbiculare
symptoms
 Lesions on fruit and leaves which
may develop salmon pink spore
masses during periods of wet
weather
 Cause
 Fungus
 Comments
 Favors wet conditions
 Management
 Rotate crops with non-cucurbits
every 1-2 years to prevent disease
build-up; plant only disease free,
treated seed

9. Alternaria leaf spot
Alternaria spp.
Symptoms
 Irregularly shaped or circular
dark brown lesions on leaves;
lesions may occur in
concentric circles
 Cause
 Fungus

10. Charcoal rot
Macrophomina phaseolina
Symptoms
 yellowing, dying leaves;
water-soaked lesion on stem
at soil line; stems oozing
amber gummy substance;
stem drying and turning tan
brown in color; lesion may
girdle stem and kill plant;
 Cause
 Fungus

11. Downy mildew
Pseudoperonospora cubensis
Symptoms
 Dead or dying leaves; yellow
to brown lesions on the upper
side of leaves; purple growth
developing on the underside
of leaves
 Cause
 Fungus

12. Watermelon mosaic
Watermelon mosaic virus (WMV)
Symptoms
 Symptoms vary widely
depending on species,
cultivar, virus strain and
environmental conditions;
symptoms on leaves may
include green mosaic
patternation, green vein-
banding, chlorotic rings and
disfigured leaves
 Cause
 Virus

13. Zucchini yellow mosaic
Zucchini yellow mosaic virus (ZYMV)
Symptoms
 Infected plants are severely
stunted and leaves can
exhibit a variety of symptoms
including yellow mosaic
patternation, severe
deformation, blistering,
reduced size and necrosis;
fruits are deformed
 Cause
 Virus

14. Monosporascus vine decline
Monosporascus cannonballus
Symptoms
 Leaves turning chlorotic;
sudden collapse of plant
canopy 1-2 weeks before
harvest; root lesions generally
become evident several days
after plant death; lesions
become covered in black dots
(fungal fruiting bodies)
 Cause
 Fungus

15. Powdery mildew
Podosphaera xanthii
Erysiphe cichoracearum
Symptoms
 White powdery growth on the
upper surfaces of leaves and
stems; infected areas stunted
and distorted
 Cause
 Fungus

16. Squash mosaic
Squash mosaic virus (SqMV)
Symptoms
 Symptoms vary with variety
being grown but plants can show
symptoms which include
include green veinbanding,
mottled leaves, blisters, ring
spots or potruding veins at leaf
margins; some squash varieties
may develop leaf enations;
infected plants are often stunted
and fruits may be malformed
with mottled skin
 Cause
 Virus

17. Angular leaf spot
Pseudomonas syringae
Symptoms
 Small water-soaked lesions on
leaves which expand between
leaf veins and become angular in
shape; in humid conditions,
lesions exude a milky substance
which dries to form a white crust
on or beside lesions; as the
disease progresses, lesions turn
tan and may have yellow/green
edges; the centers of the lesions
dry and may drop out leaving a
hole in the leaf
 Cause
 Bacterium

18. Bacterial wilt
Erwinia tracheiphila
Symptoms
 Wilting of individual runners
or entire plant; leaves and
stems of affected parts turn
dark green; wilting is
irreversible; affected parts
turn necrotic
 Cause
 Bacterium

19. Cucumber mosaic
Cucumber mosaic virus (CMV)
Symptoms
 Plants are severely stunted;
foliage is covered in distinctive
yellow mosaic; leaves of plant
curl downwards and leaf size is
smaller than normal; flowers on
infected plants may be deformed
with green petals; fruits become
distorted and are small in size;
fruit is often discolored
 Cause
 Viruses

20. Verticillium wilt
Verticillium dahliae
Symptoms
 Symptoms generally appear
after fruit set; chlorotic leaves
which develop necrotic areas;
leaves collapsing; symptoms
only on one side of vine;
discoloration of vascular
tissue in roots
 Cause
 Fungus

21. Fusarium Wilt (Fusarium
oxysporum f. sp. niveum)
 Eventually, the plant dies. The
roots are not affected. In older
plants, leaves wilt suddenly and
vascular bundles in the collar
region become yellow or brown.
 Control: Three sprays of
Karathane (6 g in 10 litres of
water) or Bavistin (1 g /litre of
water) immediately on
appearance of initial symptoms
at 5-6 days interval controls the
disease. Leaves of fully grown
vines should be thoroughly
drenched during spraying.
Symptoms:

22. Alternaria leaf blight
Alternaria cucumerina
Symptoms
 Small, yellow-brown spots
with a yellow or green halo
which first appear on the
oldest leaves; as the disease
progresses, lesions expand
and becone large necrotic
patches, often with
concentric patternation;
lesions coalesce, leaves begin
to curl and eventually die
 Cause
 Fungus

23. Cercospora leaf spot
Cercospora citrullina
Symptoms
 Initial symptoms of disease
occur on older leaves as small
spots with light to tan brown
centers; as the disease
progresses, the lesions enlarge to
cover large areas of the leaf
surface; lesions may have a dark
border and be surrounded by a
chlorotic area; the centers of the
lesions may become brittle and
crack
 Cause
 Fungus

24. Septoria leaf spot
Septoria cucurbitacearum
Symptoms
 Initial symptoms of disease are
small dark water-soaked spots
on the leaves which turn beige to
white in dry conditions; lesions
develop thin brown borders and
the centers may become brittle
and crack; small white spots may
erupt on the surface of infected
butternut and acorn squash and
pumpkin fruit
 Cause
 Fungus