water melon a lecture on tot training of ffs by mr allah dad khan provincial coordinator ipm kpk...
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Water Melon Diseases A
Lecture To ToT trainees ( FFS) By
Mr. Allah Dad Khan Provincial Coordinator
IPM KPK MINFAL Pakistan
Root knot nematodeMeloidogyne 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
CauseNematode
Southern blight (Stem and fruit rot)Sclerotium rolfsiiSymptoms
Sudden wilting of leaves; yellowing foliage; browning stem above and below soil; browning branches; stem may be covered with fan-like mycelial mat
CauseFungus
Fusarium wiltFusarium 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
Gummy stem blightDidymella bryoniaeSymptoms
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
CauseFungus
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 FungusComments Favors wet conditionsManagement Rotate crops with non-cucurbits
every 1-2 years to prevent disease build-up; plant only disease free, treated seed
Alternaria leaf spotAlternaria spp. Symptoms
Irregularly shaped or circular dark brown lesions on leaves; lesions may occur in concentric circles
CauseFungus
Charcoal rotMacrophomina phaseolinaSymptoms
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;
CauseFungus
Downy mildewPseudoperonospora cubensisSymptoms
Dead or dying leaves; yellow to brown lesions on the upper side of leaves; purple growth developing on the underside of leaves
CauseFungus
Watermelon mosaicWatermelon 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
CauseVirus
Zucchini yellow mosaicZucchini 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
CauseVirus
Monosporascus vine decline
Monosporascus cannonballusSymptoms
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)
CauseFungus
Powdery mildewPodosphaera xanthiiErysiphe cichoracearumSymptoms
White powdery growth on the upper surfaces of leaves and stems; infected areas stunted and distorted
CauseFungus
Squash mosaicSquash 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
CauseVirus
Angular leaf spotPseudomonas syringaeSymptoms
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
CauseBacterium
Bacterial wiltErwinia tracheiphilaSymptoms
Wilting of individual runners or entire plant; leaves and stems of affected parts turn dark green; wilting is irreversible; affected parts turn necrotic
CauseBacterium
Cucumber mosaicCucumber 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
CauseViruses
Verticillium wiltVerticillium 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
CauseFungus
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:
Alternaria leaf blightAlternaria 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
CauseFungus
Cercospora leaf spotCercospora 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
CauseFungus
Septoria leaf spotSeptoria 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
CauseFungus
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