When spraying trees, thorough coverage of all foliage and fruit is essential. It is necessary to apply a spray to the point of run-off to accomplish this. When applying pesticides, avoid spraying during brisk winds or during rain as coverage will be poor and so will retention of the product in the tree. The first problem of the season, and the one most often overlooked until it is too late is apple scab. There are now apple varieties that are resistant to this disease and do not have to be sprayed for control of apple scab.
Apple scab is caused by a fungus that thrives during wet weather.
To control this disease a protective fungicide layer must be maintained over the leaves and fruit during the season. This protection must start when the first green tissue just begins to peek out of the buds. It is better to spray before a rain so there is fungicide protection present to stop any potential infection. Begin spraying with a fungicide at green tip and repeat every 7 days until the blossoms open and the tree is in flower. Dikar WP also has the added advantage of controlling another fungus disease called Powdery Mildew and suppressing an insect called the European Red Mite.