Controling Fruit Tree Diseases
The woolly aphis has its own particular parasite-the Aphelinus mall. Some people collect apple shoots in late October, bearing the parasitized woolly aphides in order to store them in a shed where they can be kept at a temperature of 38-40 F.
For instance, a disease known as Silver Leaf in plums, and maybe in other top fruits also, may be cured by slitting the bark with a pruning knife right down the main branches and stem, preferably on the north side.
A sensible scheme is to remove alternate trees diagonally in the rows, as shown in the plan.
The work should be done in May or early June, if possible, and if the tree is seriously affected with silver leaf, it may show some sign of the disease next year. In this case, the bark should be re-split from top to toe and that should do the trick. In very bad cases one may have to continue this bark cutting for four years.
The compound when warmed was applied by a woman using a short stick, both to the spurs and branches and, in fact, anywhere- where it was considered a bird could conveniently perch.
Therefore, it is worth while tackling neglected trees carefully and gradually getting them right. The only exception to the rule, perhaps, is in the case of an orchard where there are gaps which amount to 25 per cent.
