Apple scab is one of the most serious diseases affecting apple because the resulting loss supersedes any other losses resulting from other apple diseases. Infection by this disease can significantly reduce fruit yields and fruit quality and lower storage capacity and loss of tree shoot system.
The reduction in yields occur due to early fall of fruits caused by infection as well as by fruit distortion and irregular and incomplete growth. Loss of shoot system in severe infection stages when scab spots cover most of leave surface. Such loss often leads to tree weakening resulting in the failure of buds creation and could also lead to failure in next season fruiting. The loss resulting from reduction of fruit quality and lower storage capacity is considered the most serious aspect of the disease for apple farmers.
To prevent the disease you can use the pesticides (Amwag – Fenzol – Ortiva – Carbazim – Combedazim – Penzol) in the following periods:
- First spray: before or at bud bursting period.
- Second spray: at green budding (at the appearance of little green leaves and before the appearance of flower buds).
- Third spray: at the appearance of flower buds (before petal burst).
- Fourth spray: After the fall of 80% of flower petals (i.e. after knotting).
- Fifth spray: when fruits are the size of chickpea (i.e. two weeks after the previous spray).