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, and fire blight. Important academic keywords: pathogen, symptoms, disease cycle, management, resistant varieties.
Introduction to Apple Diseases
  • Apple is affected by several fungal and bacterial diseases.
  • Major diseases include apple scab, powdery mildew, fire blight, and crown gall.
  • Effective management requires understanding pathogen biology and integrated control methods.
Major Apple Diseases and Causal Agents
  • Apple scab: Venturia inaequalis
  • Powdery mildew: Podosphaera leucotricha
  • Fire blight: Erwinia amylovora
  • Crown gall: Agrobacterium tumefaciens
  • Other diseases: Black rot, sooty blotch, flyspeck, Phytophthora crown rot
Apple Scab – Pathogen and Distribution
  • Caused by Venturia inaequalis (fungus).
  • First reported in Sweden (1819); in India, on Ambri variety in Kashmir (1935).
  • Favored by cool, moist conditions during spring.
Apple Scab – Symptoms
  • Black, circular, velvety spots on upper leaf surface; may coalesce.
  • Leaves become twisted, yellow, and may drop prematurely.
  • Fruits show sooty, gray-black lesions that become sunken and tan.
  • Severely affected fruit may crack and drop early.
Apple Scab – Disease Cycle and Spread
  • Primary inoculum: ascospores from fallen leaves in spring.
  • Secondary spread: conidia dispersed by wind and rain.
  • Infection favored by wet weather during bud break and early fruit development.
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 gray powdery patches on young leaves, shoots, and fruits.
  • Leaves become narrow, curled, and distorted; twigs covered with powdery mass.
  • Affected fruits are small, deformed, and roughened.
Powdery Mildew – Disease Cycle and Management
  • Overwinters as mycelium in buds and fruits.
  • Spread by wind-borne conidia in spring and summer.
  • Sanitation: remove infected shoots and plant debris.
  • Spray lime sulphur (1:60) pre-bloom; dinocap (0.05%) or wettable sulphur.
  • Resistant varieties: Maharaja Chunth, Golden Chinese, Yantarka Altaskya, Dolgoe.
Fire Blight – Pathogen and Symptoms
  • Caused by Erwinia amylovora (bacterium).
  • Affects blossoms, shoots, branches, and sometimes rootstock.
  • Blossoms become water-soaked, then brown to black and shriveled.
  • Shoots wilt, forming "shepherd’s crook"; leaves blacken along veins.
  • Infected fruit shrivel, turn black, and may remain attached.
Fire Blight – Disease Cycle and Spread
  • Bacteria overwinter in cankers and healthy woody tissue.
  • Spread by insects (bees, flies, ants) and rain splash.
  • Infection occurs during warm, humid weather, especially at bloom.
Fire Blight – Management
  • Prune and burn infected twigs and branches 30 cm below visible symptoms.
  • Disinfect tools with 10% sodium hypochlorite after each cut.
  • Control insect vectors.
  • Use resistant varieties where available.
  • Dormant sprays: copper sulphate or Bordeaux mixture; streptomycin for blossom protection.
Other Important Apple Diseases (Brief Overview)
  • Cedar apple rust: Gymnosporangium juniperi-virginianae – orange leaf spots, fruit lesions.
  • Crown gall: Agrobacterium tumefaciens – tumor-like galls on roots and stems.
  • Black rot: Botryosphaeria obtusa – fruit rot, leaf spots, cankers.
  • Sooty blotch and flyspeck: superficial fruit blemishes, reduce market value.
  • Phytophthora crown, collar, and root rot: Phytophthora spp. – root decay, tree decline.
Summary: Integrated Disease Management in Apple
  • Combine cultural, chemical, and genetic approaches for effective control.
  • Regular orchard sanitation and pruning are essential.
  • Use disease-resistant varieties when possible.
  • Apply fungicides and bactericides judiciously, following recommended schedules.
  • Monitor orchards regularly for early detection and management.