Scab: Venturia inaequalis
Symptoms
- Symptom appears on leaves and fruits.
- On lower side of the leaf lesion appear 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 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 |
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