Ppt on Major Diseases Of Apple And Their Management Strategies

This presentation covers major diseases of apple, focusing on their causal agents, symptoms, disease cycles, and management strategies. Emphasis is placed on accurate identification and integrated management for sustainable apple production. Key topics include apple scab, powdery mildew, fire blight, and crown gall. Important academic keywords: pathogen, symptoms, disease cycle, management, resistant varieties.

Introduction to Apple Diseases

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Apple is susceptible to various fungal, bacterial, and physiological diseases.
Major diseases impact yield, fruit quality, and tree longevity.
Effective management requires understanding pathogen biology and disease cycles.
Integrated approaches combine cultural, chemical, and genetic methods.

Apple Scab – Pathogen and Distribution

Caused by Venturia inaequalis (fungus).
First reported in Sweden (1819); in India, Kashmir valley (1935).
Most economically important apple disease worldwide.

Apple Scab – Symptoms

Black, circular, velvety spots on upper leaf surface; may coalesce.
Leaves become twisted, yellow, and may drop prematurely.
Fruits develop sooty, gray-black lesions, later sunken and tan.
Infected fruits may crack and become deformed; young fruits may drop.

Apple Scab – Disease Cycle and Spread

Primary inoculum: ascospores from fallen leaves in spring.
Ascospores dispersed by wind and rain during wet periods.
Secondary spread: conidia dispersed by wind and rain.

Apple Scab – Management

Sanitation: remove and destroy fallen leaves.
Use resistant varieties: Emira, Redfree, Ambstraking, Ambroyal, Ambrich, Ambred.
Fungicide sprays: captan (0.2%), dodine (0.25%) after petal fall.
Apply difolatan (0.3%) at green bud stage, followed by captan at petal fall.

Powdery Mildew – Pathogen and Symptoms

Caused by Podosphaera leucotricha (fungus).
White or grey powdery patches on young leaves, shoots, and fruits.
Leaves become narrow, curled; twigs covered with powdery mass.
Fruits remain small, deformed, with roughened surface.

Powdery Mildew – Disease Cycle and Management

Overwinters as mycelium in buds; spreads by wind-borne conidia.
Sanitation: remove infected shoots and plant debris.
Pre-bloom spray: lime sulphur (1:60); fungicides: dinocap (0.05%).
Resistant varieties: Maharaja Chunth, Golden Chinese, Yantarka Altaskya, Dolgoe.

Fire Blight – Pathogen and Symptoms

Caused by Erwinia amylovora (bacterium).
Affects blossoms, shoots, branches, fruits, and rootstock.
Blossoms become water-soaked, turn brown/black, shrivel.
Shoots wilt, forming “shepherd’s crook”; leaves blacken along veins.
Milky, sticky ooze may appear on infected tissues.

Fire Blight – Disease Cycle and Management

Bacteria overwinter in cankers and woody tissue.
Spread by insects (bees, flies, ants) and rain splash.
Prune and destroy infected parts 30 cm below visible symptoms.
Disinfect tools with 10% sodium hypochlorite after each cut.
Dormant sprays: copper sulphate or Bordeaux mixture; streptomycin for blossom protection.

Crown Gall – Pathogen and Symptoms

Caused by Agrobacterium tumefaciens (bacterium).
Galls form on roots and stems near soil line; initially white/flesh-colored, later hard and corky.
Plants become stunted with chlorotic leaves.

Crown Gall – Management

Use disease-free planting material; avoid wounding roots and stems.
Crop rotation with cereals or maize.
Biological control: Agrobacterium radiobacter strain K1026 applied to wounds.
Penicillin or vancomycin offers partial control.

Summary: Integrated Disease Management in Apple

Combine cultural, chemical, and genetic resistance strategies.
Regular monitoring and early detection are essential.
Sanitation and removal of infected material reduce inoculum.
Use of resistant varieties minimizes chemical dependence.

Author: admin

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