The feeding of apples is important, particularly potash feeding Generally speaking, you can tell what foods are deficient in the so by watching the trees. If a tree grows well and makes long new ti to its leaders and plenty of leaf growth, it has a sufficiency of nitrogen If it flowers well it has sufficient phosphates. If it appears generally healthy, free from disease and with plenty of colour in flower and foliage and fruit, it has sufficient potash. If the edges of the leaves turn brown, potash is probably lacking. If the centres of the leaves turn brown, the tree needs phosphates.
An annual dressing of lime in the winter, and of kainit in autumn or winter, is advisable on apples, and both supply potash (kainit contains potash, and lime releases it from the soil).
Sulphate of ammonia or nitrate of soda applied in spring will supply nitrogen. Basic slag in autumn on heavy, rich soils, or super phosphate of lime in spring on light sails, will supply phosphates.
Apples fed and pruned carefully are not troubled so readily by pests and diseases, but a certain amount of preventive spraying should be done. Bordeaux mixture or lime sulphur are useful mildew and similar diseases, but care should be taken not to apply these too strong.
Pests include such general pests as greenfly and woolly aphis Greenfly is controlled by any ordinary insecticide used as a spray or dust. Woolly aphis, which resembles bits of cotton-wool on the bark, is best attacked by painting the patches with methylated spirit or petrol. The maggot of the apple sawfly causes fruits to drop in early summer. The remedy is to dust Derris powder over the branches and leaves in the late evening.
Cedlin moth causes fruit dropping later in the season, and this is a troublesome pest to eradicate. The use of soil fumigant in early spring, tar-oil winter wash, and traps of sacking are ways to treat it. Sacking should be folded fanwise and pushed into the fork of the branches in August. In winter the sacking can be removed and burnt or dropped into strong insecticide. The alternative treatment for codlin moth is to use arsenic spray before and after the flowers open, but as there is a slight danger of the spray remaining after the fruit ripens, this should be considered only as a last resort in the home garden.