DISEASED PLUMS.

Timaru Herald, Volume LXXXII, Issue 848, 2 December 1905, Page 7

DISEASED PLUMS.

A week or so ago we published a paragraph regarding a peculiar disease which had affected some plum tree*; in tie neighbourhood of Timaru, and stated that specimens had been sent to Wellington through Mr Huddleston, for examination. Mr Huddleston has received' a'reply from;- Mr- T. W. Kirk, the Government Biologist, stating that- the phnn trees are attacked by a fungus disease known as "plum pockets," and a leaflet was enclosed which, deals with tb Thif S 18 of the Leaflets for Gardeners and Fruitgrowers," first; issued in 1897, and revised' and; reissued on March last. It states that the- disease is variouslv named "bladder plums," "pocket plums," " mock plums," " 6tarved plums," end " Exoascus 'pTuni" ; and it is described: as follows-.

This destructive plum-tree dfeease, closely allied to the peach-curl, is only too familiar in older countries, and is greatly on the increase here.. It , is caused by a minute fungs that lives parastically. in the tissues of tie young branches. In the spring, just as the trees *ure beginning to blossom, part of the mycelium of the fungus, extends from the interior of the branches and enters the young ojaxies'of , the flower. It then permeates thr6t»gb ; the developing fruit and' prevents the formation of the stone, and, instead of developing into normal plums, the fruit becomes deformed and / hollow. These bladdier o; pocket plums, -as .they; are called, are of variable size and shape, being hard, furrowed, and generally,curved and flattened. They finally, diy up and fall from the, tree. - In the earlier stages they appear * to be covered with a grey, felty bloom; this is, in reality, the fruit, of the fungus, and if examined" under a microscope it will foe seen to eonsist of immense -numbers _of club-shaped cells, in each of which are developed eight spores. These cells or asci.arise from the mycelium*, of the fungus imbedded in. the bladder-plums, and they burst through the skin so that the spores may the more easily be disseminated. Japanese plums, are especially liable to the attacks of this disease. As tie mycelium perennates within the tissues of the young branches, and as only the spores are developed on the surface of

the plant, it follows that external applications are not in themselves entirely satisfactory in repressing this disease. Tress which are not badly diseased should have all the affected branches carefully pruned back beyond the point where the fungus shows itself, and the prunings should be carefully .burnt. If this pruning is systematically carried out the perennial mycelium will soon be destroyed, and thus the disease eradicated. All fallen and diseased fruit should be raked up and burnt, while all very bady affected and neglected trees should be destroyed, as they only serve as nurseries for the infection of healthy orchards. Spraying with Bordeaux mixture is exceedingly beneficial, both in repressing the growth of the fungus and also in preventing the infection of healthy branches and trees by means of the spores. All trees should therefore be dressed with Bordeaux mixture before the buds expand and; at intervals until the fruit is set-.

Directions for making Bordeaux mixture : 41b sulphate of copper, 41b fresh lime, 50 gallons ef water. Dissolve the copper in, say, 5 gallons of water in a wooden vessel. The best way is to tie it in a loosely woven bag, and suspend the bag from a stick laid across the tub; or, if in a hurry, use hot water, slack the lime in another vessel, and; add it to the copper solution; stir well till thoroughly mixed, then add sufficient water to bring the whole up to 50 gallons. Now strain out any dirt. Apply with a proper spray-pump with a cyclone or Bordeaux nozzle. Tiis liquid should not be kept for more than a day; after that time any left over should be thrown away and fresh mad?. , A stock solution may, however, be inade' |ps follows: Dissolve, isay, 1001b of sulphate <>f copper in 25 gallons of water. This, jvhich is called milk of lime, is to be kept airtight, and will then remain good for J-bout a week. When the mixture is required, take I 5 gallons of sulphate of copper solution and strain into 19 gallons of water. Then take 1 gallon of milk of lime and strain slowly into the copper solution; -keep stirring until a sky-blue colour is obtained. The Bordeaux .mixture is thai ready for use, and my be diluted further with water if full strength solution is not needed.