Disease of Cucurbits plants
Anthracnose of Cucurbits
Causal organism: Colletotrichum lagenarium.
Symptoms
Seedling stage Cotyledons drop and wilt, lesions on stem near the ground.
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| Sypmtoms of Anthracnose of Cucurbits |
Foliage
1. Spots as small yellowish or water soaked areas enlarge rapidly and turn brown almost cucurbits.
2. The dry dead tissues break and shatters; whole leaf dies.
3. Petioles become affected. Stem Elongated lesions with foliage destruction kill whole vine. Fruits and
Pedicel
1. Affected young fruit darken, shrivel and die (water melon).
2. Fruits are roughly circular, sunken, cankers and black.
3. When moisture present, centre of black lesion is lined with coloured gelatinous mass and spores.
Host crop Cantaloupe, squash and pumpkin are less susceptible to anthracnose.
Favorable Condition
Warm, humid and rainy weather at frequent intervals is necessary for disease development.
Transmission
Wash water, cultivating equipments, cucumber beetle can carry the spores.
Control Measure
♦ Use resistant varieties.
♦ Field sanitation should be done.
♦ Crop rotation should be followed.
♦ Eradication of alternate host like Weeds, Wild Cucurbits etc.
♦ Using proper fungicide and insecticides.
Powdery mildew of Cucurbits
Causal organism: Erysiphe cichoracearum.
Symptoms
Leaves
1. Foliar first sign as a whitish talcum like powdery growth under surface of the shaded crown leaves.
2. Areas of white powdery growth expand and coalesce and cover leaf surface.
3. Affected leaves wither and finally become dry and die.
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| Sypmtoms of Powdery mildew |
Fruits
1. Premature ripening.
2. Poor flavour and texture.
3. Poor quality of fruits.
4. Pimping/patches of white mold on fruits.
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| Sypmtoms of Powdery mildew |
Favourable condition
♦ Temperature 25 C or above.
♦ Relative humidity 70%.
Control Measure
1. Use resistant varieties.
2. Plant in areas with good air drainage and allow for maximum air circulation.
3. Crop rotation and fall plowing are of no benefit because the fungus does not survive in the field.
4. Sufficient spray of Thiovit (S containing)/Sodium bi carbonate @ 0.2 % solution.
5. Field sanitation.
Downy mildew of Cucurbits
Causal organism: Pseudoperonospora cubensis.
Symptoms
1. First symptom appears as mosaic; Pale green areas separated by darker green, turn into yellow angular spots bounded by leaf veins.
2. In moist weather; Corresponding lower surface of leaf, covered with purplish fungus fruiting layer.
3. Colour changes almost white to black, entire leaf dries quickly.
4. May be dwarf with poor flavor (Muskmelon).
5. Fruit is covered with fungal growth.
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| Sypmtoms of Downy mildew |
Control Measure
♦ Wide spacing between plants.
♦ Good drainage system.
♦ Spray fungicide Dithane M45/Redomil/Dithane Z78 @ 0.2 % solution.