Disease forecasting

Disease forecasting based on symptoms

Ber
White mealy growth on leaves and fruits.

Disease/pest: Powdery mildew
Casual organism: Oidium erysiphoides f.sp. zizyphi
Visual symptoms:
Symptoms:
White mealy growth on leaves and fruits. The disease causes premature defoliation and heavy fruit-drop. Affected fruits remain small and become cankered and disfigured.
Remedy:

  • Spraying of dinocap 0.05 per cent or wettable sulphur 0.25 per cent should be done during first and third weeks of November or when the fruit attains pea size.
  • Triton-AE or Teepol or Sandovit may be added for adhesion.

Formation of small irregular’ brown spot on the upper surface of the leaves.

Disease/pest: Alternaria leaf spot
Casual organism: Alternaria chartarum Isariopsis
Visual symptoms:
Symptoms:
The disease is characterised by the formation of small irregular’ brown spot on the upper surface of the leaves. On the lower surface dark brown to black spots are formed.
Remedy:

  • The disease can be controlled effectively by spraying Mancozeb 0.25 per cent

Light russet vinaceous coloured, irregular spot on the fruits.

Disease/pest:Soft rot
Casual organism: Phomopsis natsume
Visual symptoms:
Symptoms:
The disease appears as a light russet vinaceous coloured, irregular spot on the fruits.

It increases in size and make the whole fruit into pulpy, brown to black in colour with soft and loose outer skin.
Remedy:

  • The disease can be-controlled by spraying with Carbendazim 0.05 per cent.

Fruits become deformed, turn brown and rot.
Period of activity: June to September

Disease/pest: Fruit flies
Casual organism: Bactrocera zonata
Visual symptoms:
Symptoms:
The infested fruits become deformed, turn brown and rot. In north India, up to 80% fruits are damaged. Thin skinned, soft and sweet cultivars are more susceptible.
Period of activity: June to September
Remedy:

  • Total 3 sprays of Dimethoate (0.03%) followed by Phosphamidon (0.03%) and carbaryl (0.1%) at 10-12 days interval should be given. In spray fluid add 0.5% jiggery.

Small holes on the fruits.

Disease/pest: Fruit borer
Casual organism: Meridarchis scyrodes
Visual symptoms:
Symptoms:
Eggs are laid on fruits at pea stage. on hatching caterpillars bore into fruits and feed on the pulp near seed.
Period of activity: October to February

Remedy:

  • Cultivated resistant varieties like Gola, Banarsi Derakhi.
  • Collect the fallen fruit and destroy. Harvest fruit at early stage when they are still green but fully mature.

Folded leaves and stunted growth on growing point.
Period of activity: August to September

Disease/pest: Leaf-eating caterpillars
Casual organism: Euprocitis fraterna
Visual symptoms:
Symptoms:
The newly hatched caterpillar attacks unopened and partially opened leaves and leaf folding with silken threads. The larvae consumes green matter by scrapping, leaving behind the papery epidermis. In severe state, the tree gives unhealthy appearance and stunted growth on growing point.

Period of activity: August to September

Remedy:

  • Application of quinalphos 2ml/liter or carbaryl 2g/liter during new vegetative flush and repeat the spray after 3 weeks found effective.

Cumin