Diseases
Apple scab: when to protect
The disease that decides many spray plans, and the stages that matter most.
Relevant stages: Green Tip, Tight Cluster, Pink Bud, Flowering, Petal Fall, Fruit Let, Fruit Development IV.
Scab causes dark spots on leaves and fruit and spreads in wet weather.
The critical stage
The SKUAST guide calls pink bud "a crucial stage for primary scab infection". Monitor closely and watch the weather.
Protection through the season (from the guide)
- Green tip: Mancozeb 75WP, 300 g per 100 L, before the onset of full-day rain. Skip if it has been dry 7+ days.
- Tight cluster: Mancozeb again if rain is forecast, skip if dry 7+ days.
- Pink bud: Zineb 68% + Hexaconazole 5%, 125 g per 100 L, if the weather is dry.
- Petal fall: Difenaconazole 25EC, 30 ml per 100 L, before rains.
- Fruit let: Zineb + Hexaconazole before rains.
- Fruit development IV: Zineb + Hexaconazole 4% if scab or Alternaria is present.
Wet spells
Long wet spells can cause a secondary spread of scab in summer. Inspect leaves and fruit after prolonged rain and follow current SKUAST-Kashmir advisories.
Good practice
- Remove scab-infected leaves before the rains, and infected fruits at fruit let.
- Keep the orchard clean of debris.
- Always read the label and check the pre-harvest interval.
General guidance. Always read product labels and consult an agronomist for problems specific to your orchard.
