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Fruits > Apple>
Diseases
Apple Scab (Venturia inaequalis)
:
Apple scab affects both leaves and fruits. Scattered,
circular brown or olive-green spots appear on
the undersurface of leaves borne on fruit-spurs.
Initially the lesions cover a large portion of
the leaf leading to premature yellowing of leaves,
defoliation and fruit drop. Early in the season,
these spots often develop around blossom end (calyx
end) of the fruit and later they are found anywhere
on the fruit surface. Cracks often develop in
the scabbed areas, which allow the entry of other
pathogens, causing rot of fruit either in the
field, or in storage.
Control :
The spray schedule recommended for effective control
of scab disease is as follows
| Stage |
Fungicide/100 litres of water. |
| Silver tip-Green
tip |
Mancozeb (400 g)/Captan (300 g). |
| Pink bud |
Contaf (30 ml)/ Baycor (50 g). |
| Petal fall |
Bavistin (50 g)/Topsin M (50 g). |
| Pea stage |
Mancozeb (300 g)/Captan (300 g). |
| Fruit development
|
Bavistin + Mancozeb (25+250 g). |
| 15-20 days before
harvest |
Mancozeb (300 g). |
| Before leaf fall
|
Urea (5 kg). |
(ICAR : 50 years of crop science
research in India, 1996)
Fire Blight (Erwinia amylovora)
:
This disease is caused by bacteria. The symptoms
are seen as distinct fire-like appearance on infected
plant parts. New shoots are highly susceptible
to infection. The shoot tips wilt and droop without
browning. Secretion of golden coloured bacterial
ooze is seen on the stem. In fruits, Necrotic
spots and oozing lesions are observed on the outer
surface of the fruit surface.
Control :
The affected trees and host plants should be collected
and burnt immediately on observing the incidence
of fire blight. Sprays of streptomycin can control
the infection in spring blossom of apple.
Powdery Mildew (Podosphaera
leucotricha) :
Powdery mildew is a serious disease affecting
buds, new shoots and leaves. The disease appears
in the dry climatic conditions. The nursery plants
are more prone to this disease. The diseases is
characterized by the presence of white powdery
(ash like) coating in patches on both sides of
the leaves, and young shoots. The affected leaves
turn pale and curl up. Affected shoots remain
weak and immature. In case of severe infection,
leaf fall and pre-mature fruit drop may occur.The
young infected fruit show signs of russeting.
Control :
The disease incidence can be reduced by pruning
and destroying the affected plant parts. In the
nurseries, spraying the young seedlings with Bayleton
(500 ppm) at an interval of 7 days controls the
disease. In the field, fungicidal sprays should
be taken after pruning of the affected plant parts.
Spraying the crop with Sulphur (0.3%) or Carbendazim
(0.05%) or Karathane (0.05%) effectively controls
the disease.
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