Apple: Diseases, Symptoms and their Management
Apple is a major fruit crop grown primarily in temperate climates around the world. Among temperate fruits, the apple is a highly cultivated fruit crop in India. The apple is also known as the “King of Temperate Fruit,” the “Symbol of Health,” the “Premier Fruit of the World,” and “An Apple a Day Keeps the Doctor Away.”
In this post, we discussed some of the most important diseases of apple that impair fruit yield, as well as their causing organism, symptoms, and management.
Diseases of Apple
1. Apple Scab
Causal Organism: Fungus; Venturia inaequalis.
- First reported from Sweden (1819).
- In India first reported on the Ambri variety of Apple in Kashmir valley (1935).
- Epidemic in Kashmir valley in 1975 and in Himachal Pradesh in 1981.
- Apple scab affects both leaves and fruits.
- The lesions first cover a substantial area of the leaf, causing premature yellowing, defoliation, and fruit loss.
- On the undersurface of leaves, the spots are velvety and may coalesce to cover the whole leaf surface.
- Severely affected leaves may turn yellow and drop.
- Use Resistant varieties: Emira, Red free, Ambstraking, Ambroyal, Ambrich and Ambred.
- Spray captain @ 0.2% or dodine @ 0.25% at short intervals after petal fall.
- Single application of difolaton @ 0.3% at green bud stage followed by captain @ 0.2% at petal fall.
2. Fire Blight
Causal Organism: Bacteria; Erwinia amylovora
- The symptoms are visible on infected plant parts with a unique fire-like look.
- New shoots are extremely vulnerable to infection.
- The shoot tips wilt and droop but do not discolour.
- On the stem, golden-coloured bacterial ooze is secreted.
- On the exterior surface of the fruit, necrotic patches and seeping sores can be seen.
- Sprays of streptomycin can control the infection in the spring blossom of apple.
3. Powdery Mildew
Causal Organism: Fungus; Podosphaera leucotricha
- Powdery mildew affecting buds, new shoots and leaves.
- The disease appears in dry climatic conditions.
- White powdery (ash-like) coating on both sides of the leaves and young shoots are characteristic of the disease.
- The affected leaves turn pale and curl up.
- Spraying the crop with Sulphur (0.3%) or Carbendazim (0.05%) or Karathane (0.05%) effectively controls the disease.
4. Blue Mold
Causal Organism: Fungus; Penicillium digitatum.
- Affect mature fruit only (Post-harvest disease)
- Watery areas begin around injuries or lenticels on the fruit surface.
- Characteristically mouldy odour and flavour.
- Greyish-blue masses of spores appear on the fruit surface.
Hello, I am Sonu Verma, M.Sc. (Horti.) Agriculture content writer, and an enthusiast who loves to share knowledge. No Culture Without Agriculture.