Major Apple diseases are given below:-
1.Apple Scab: Venturia inaequalis
Symptom:
- Symptom appears on leaves and fruits.
- On the lower side of the leaf, the lesion appears as olivaceous spots which turn dark brown to black and become velvety.
- On young foliage, the spots have a radiating appearance with a feathery edge.
- On older leaves, the lesions are more definite in outline.
- The lesion may form a convex surface with the corresponding concave area on the opposite side.
- In severe infection leaf blade curved, dwarfed and distorted.
- Fruits show small, rough, black circular lesions.
- The centre of the spots become corky and on mature fruits, yellow halo is seen around the lesions.
Management:
- Clean cultivation, collection and destruction of fallen leaves and pruned materials in winter to prevent the sexual cycle.
- Spray Tridemorph 0.1% before flowering.
- Spray Mancozeb 0.25 % at bearing stage.
- Spray 5 % urea prior to leaf fall in autumn and 2 % before bud break to hasten the decomposition of leaves.
|
S.No |
Tree stage |
Fungicide/100lit |
|
1 |
Silver tip to given tip |
Captafol 200 gm (or) Captan 300 g or Mancozeb 400 g |
|
2 |
Pink bud or 15 days after 1 st spray |
Captan 250 g or Mancozeb 300 g |
|
3 |
Petal fall |
Carbendazim 50 g |
|
4 |
10 days later |
Captan 200 g.or Mancozeb 300g |
|
5 |
14 days after fruit set |
Captofol 150 g |
-
Add stickers – teepol or triton 6 ml/10 lit of spray fluid.
2.Powdery mildew: Podosphaera leucotricha
Symptom:
- Small patches of white powdery growth appear on the upper side of leaves.
- In a severe case, the symptom appears on both the sides.
- Twigs are also infected. Affected leaves fall off in severe infection.
- Fruit buds are also affected and deformed or remain small.
Management:
- Spray Dinocap 0.05% or Chinomethionate 0.1%
3.Fire blight: Erwinia amylovora
Symptom:
- The initial symptom usually occurs on leaves, which become water soaked, then shrivel turn brownish to black in colour and fall or remain hanging in a tree.
- The symptom spread to twigs. Terminal twigs wilt from tip to downward and also spread to branches.
- Fruits become water soaked, turns brown, shrivels and finally becomes black.
- Oozing may be seen in the affected area.
Management:
-
Removal and destruction of affected parts.
-
Removal of blighted twigs
-
Spray with Streptomycin 500 ppm.
4.Soft rot: Penicillium expansum
Symptom:
- Young spots start from stem end of the fruit as light brown watery rot. As the fruit ripens area of the rotting increases,
- Skin becomes wrinkled.
- A peculiar musty odour is emitted
- Under the humid condition, a bluish green sporulating growth appears.
- Infection takes place by wounds in the skin caused by insects and during handing in storage and transport
Management:
- Careful handling of fruits without causing any wounds.
- Dipping the fruits aureofunginsol @ 500 ppm for 20 min gives the best control.
5.Bitter rot: Glomerella cingulata
Symptom:
- Faint, light brown discolouration beneath the skin develops. The discolouration expands in a cone shape. The circular, rough lesions become depressed. The lesions increased and cover entire areas of fruits.
- Tiny black dots appear beneath the cuticle which gives rise to acervuli
- Pink masses of spores are found arranged in defined rings.
Management:
- Spray Mancozeb 0.25 % in the field.
- Treatment with Mancozeb 0.25 % to check the disease in storage.
Source-
- TamilNadu Agritech Portal
