SILVER LEAF DISEASE

Wairarapa Times-Age, 22 December 1939, Page 3

SILVER LEAF DISEASE

NO GARDEN SAFE. No garden is safe from silver leaf disease, which turns fruit tree foliage from the natural deep healthy green to a sickly, silvery hue. Peaches, nectarines, plums and cherries are the trees to suffer most. If you see a branch bearing silver foliage, cut that branch clean out and burn it at once. Cut well below the silvered part and back to a point where no dark brown staining in the cut surface can be seen. The brown stain in the wood denotes that the fungus is there. At once cover the cut with a good lead paint. Only a small branch may show the symptoms now, but unless action is taken, the trouble will quickly spread from branch to branch and before long the whole tree will be ruined. When leaves have fallen from branches killed by the disease, it shows in the form of small leathery, mauvetinted encrustations on the bark; these spread the infection by means of spores. Sometimes a whole tree looks suspiciously like silver blight, with its foliage anaemic-looking, but hardly

silvered. Very often such a tree may be pulled round, for it may not be the real fungus disease, but a complaint known as “false” silver leaf, due to malnutrition.

First cut' out every piece of dead wood in the tree. Next mix sulphate of ammonia one part and sulphate of potash three parts. Apply this mixture to the ailing tree at the rate of four ounces to each square yard of ground. Scatter it evenly over the soil beneath and all round the tree and hoe into the top soil. Give a good watering and finish off with a thick mulch of animal manures laid on the soil over the roots. Leave this dressing to rot in. If you already have a tree badly “silvered," with pieces of branches dying back, burn the tree, otherwise near by trees will soon be going the same way. Silver leaf can spread from one tree to another only by means of dead wood and it can enter a healthy tree only through some wound or bark abrasion, or through bark punctures by pests. Do not, therefore, leave any primings or branch stumps lying around. Protect every kind of wound or bark abrasion, however small, with a good coating of lead paint. Spray the trees to ensure freedom from pests and to keep down the aphis which “lets in” the disease. Keep the trees growing healthily by judicious manuring, especially applying lime and potash, where these are lacking.