1. Fruit disease
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2. Introduction:
Fruit diseases are the disease that infects fruit (ripening stage).
Infection may occur in the mother tree itself but symptom expression may be in mother tree/ during harvesting time or during storage.
Fruits in the unripened stage show resistant reaction to pathogen but once, they ripened become susceptible to pathogen infection due to changes in the biochemical constitutes of fruits.
Since fruits are the final product of the plant any infection in plant directly affects the income of a farmer.
Examples for the fruit diseases are fruit rot, anthracnose and mould diseases.
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3. The period between point of infection and point of symptom expression are known as latent period.
Latent period is mostly in the tree itself and symptom expressed in storage or during marketing.
To minimize the infection pre harvest spraying with fungicides in the tree itself is important and also avoiding mechanical injury during harvesting and handling and cold storage are important.
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4. Calvibacter michiganese:
Fruit canker:
Calvibacter michiganese:
Symptoms:
On the fruit, the infection starts as is cut, creamy yellow bacterial ooze is seen.
On the fruit, the infection start as water soaked lesions, with a white halo, later turning dark brown, corky and cankerous.
At times these cankers may deep seated and cover a large portion of fruit.
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5. Control: Scab: Symptoms:
Spraying the plants with 500 ppm of streptomycin, two or three times at the fruiting stage, would also help to reduce the intensity of the disease.
Scab:
Symptoms:
The fruits are severely attacked and highly deformed. Early attacks on the fruit are very damaging.
Early lesions on fruit occur near calyx and stalk end lesions occur later.
The lesions develop on fruits even under storage.
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6. Control:
The scab disease controlled by spraying with systemic and protective fungicides such as
Benlate ( per cent),
Captan (0.2 per cent) and
Diathane M-45 (0.25 per cent).
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7. Bird eye spot: Symptoms:
The disease is first noticed by irregular corky spots on the fruits.
The spots may be a few mm up to one cm in diameter.
They become warty, erupted with cracks a scabby, hence the name.
On the fruits the warty growth are surrounded by yellowish or chlorotic haloes.
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8. The color of the spot turns from yellow to orange brown finally black.
Several spots run together to form large patches of corky out growths.
The scab may be a few or many on each fruit and the market value of the fruits is considerably reduced because of the infection, though the fungus rarely affects the fruit flesh below the skin.
Control:
The disease is controlled by spraying once or twice with Bordeaux mixture.
Other fungicides are:
Difolatan,
Benomyl,
Perenox and
Ferbam.
Sanitary practices also reduce the disease.
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9. Anthracnose: Symptoms:
The fungus attacks all plant parts above ground level and at any stage of plant growth.
Firstly water soaked lesions appear on the fruits later becoming brown, and enlarging to form circular spots of varying size.
The spots usually depressed with dark centers, and bright red, yellow or orange margins.
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10. Control:
Treating the seeds with organo mercurial will help to eliminate the external seed borne inoculums.
Spraying of the plants with Bordeaux mixture or other fungicides at 15 day interval markedly reduces the disease.
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11. Fruit canker: Symptoms: Mode of spread:
The lesions appear first as minute water soaked roundish spots, which enlarge slightly and turn brown, eruptive and corky.
The canker lesions on the fruits also vary in size and often several lesions coalesce to form a patch.
The market value of the fruits is considerably reduced by the canker spots, though such infections are mostly confined to the fruit skin.
Mode of spread:
Rain water also splashes the bacteria, which become wind – borne and spread from place to place.
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12. To sum up
Fruit diseases are the disease that infects fruit at ripening stage.
Fruits in the unripened stage show resistant reaction to pathogen but once, they ripened become susceptible to pathogenic infection due to changes in the biochemical constitutes of fruits.
Important fruit diseases are fruit rot, fruit canker, scab, bird’s eye spot, anthracnose and mould diseases.
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13. Assessment: 1. Yellow Bacterial Ooze is observed in which diseases?
a. Fruit Canker b. Anthracnose C. Scab
2. What is the chemical used for seed treatment to control the external seed borne inoulum? –Organ mercurial
3. Anthracnose affects the young fruits at the distal ends of fingers True/False True
4. Leions appear first as minute water soaked croundish spirt observed in Fruit Canker
5. Fruit Canker controlled by Streptomycin sulphate at 500 ppm
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