LEAFLETS FOR GARDENERS AND FRUITGROWERS.

Otago Witness, Issue 2250, 15 April 1897, Page 8

LEAFLETS FOR GARDENERS AND FRUITGROWERS.

No. 18. — Blauder Plu3H, Pocket Pldjis, Mock Plums, Starved Plums (Exoascus taphrina prnni, Fucke). By T. W. Kirk, P.K.M.S., F L.S., &c, London, Government Biologist. This disease is sometimes only too familiar in older countries, and is decidedly on tho incresso here. Ib attacks the fruib soon after blossoming ; the mycelium of the fungus spreads through the flesh, preventing the formation of the stone, checks the development of fruit, and causes tho elongated deformity shown in the illustration. This fungus also attacks the leaves and stems, causing swellieg and dis-

Portion of branch of plum, thowing deformed plums due to the attacks of the fungus. From Nature. tortion. These plums are hard, furrowed, and hollow, so that they have obtained the name of " pocket plums." In the early stages they look as if covered with grey felt. The Japanese plums suffered in one or two places last season from attacks of Exoascus. Treatment. — Spray early, just before tho buds begin to swell, with Bordeaux mixture ; again just before the blossoms open, and repeat later if necessary. Directions for making Bordeaux mixture : 41b sulphate of copper, 41b fresh lime, 31b common treacle, 45gal water. Dissolve the copper in, say, sgal water in a, wooden vessel. The besb way is to tie it in a loosely-woven bag, and suspend the bag from a •tick laid across the tub ; or, if in a hurry, use hot water, slack the lime iv another vessel, and add it to the copper solution ; stir well till thoroughly mixed, then add sufficient water to bring the whole up to 45gal. Now strain out any dirt ; then stir in the treacle. Apply with a proper spray-pump with a cyclone nozzle. The object of the treacle is to cause the mixture to adhere more firmly to the foliage, and so be less likely to be washed off by rain. This liquid should nob be kept for more than a day ; after that time any left over should be thrown away and fresh made. A stock solution may, however, ba made as follows: Dissolve, say, 1001b of sulphate of copper iv 25gal of water in a cask. Then, in another, dissolve 751b of fresh stone lime in 25gal of water. This, which is called milk of lime, is to be kepb airtight, and will then remain good for about a week. When the mixture is required, take l£gal of sulphate of copper solution aud strain, into 192*1 of water. Then

take lgsl of milk of lime Bud strain slowly into the copper solution; keep stirriug until a skyblue colour is obtained. The Bordeaux mixture ;* tuJ« ««-i» f™. „«» <.n,l r»iTr »,n .liin•>,,,* is then ready for use, and may be diluted further with water if full-strength solution ia nob needed. Treacle added as mentioned above. , - PiiAR-MiTG (Phytopua pyri). By T. W. Kirk, FRMS , F L S., &o , London, Government £>„-.' s •■""•> "■"■* uuuug • uioiogiso. Leaves attacked by pear-mite aro so very similar in appearance to those suffering from the microscopic fungus causing pear-scab (Fusicladium pyrinum) that many person^ mfctake the one d.saasa for the other, and thus the wrong treatment is applied, lue diseased condition being due in ono instance to a fungus and in the other to an insect-, it is manifesb thab different modes of combating them must ba adopted. The pear-mlta is vary common in this colony, as also in some parts of Australia. Its attacks •v.«., v,., n.«i. v -~n* :„ t-\, n ««»!,-,n. „.. «o-i, may ba first observed in tho spring or early summer, when tha leaves are seen to present a number of green and whitish-green blisters, which gradually increase both iv siza and quantity till thero is sometimes scarcely any portion of tho leaf which i 3 nob covered by these disfigurements which have now tamed brown in colour, and look like so m-uiy scabs The brief description of this iinte given by Dr Oobb, the eminent scientist, attrohed to

the New South Wales Department ot Agriculture, is so excsllenb, aud describes my own observations and experience in such a clear and lucid manner, that I cannob da better than quote it here : — "This liitls animal ia so sniill as to bs almbsO invisible to the naked eye. With a lens, however, they aro soon discovered on almost any leaf who3e surface is covered with their blisters. They are seen to be simll, white, elongated, slow-creepicg animal?, whose le*?, four in number, seem to bo attached near tha heads In motion they preseut the appearance of dragging their bodies alter them, or of an animal pulling a load. They are not numerous on the surface of 1 he leaf, aud Bometimeß several leaves will be examined with a lens before a mile is found ; this is because thay reside in galleries under the eurfs.ee of. tho blisters, coming out only .temporarily, and for purposes unknown. Taece cannot, however, ba much doubb that thoy do come out habitually, for moot of the blisters, and especially tha large ones, have a small circular hole at the top, which no doubt serves as a door for that purpose. Tho blifeters of a single leaf often contain several hundred mites. Ths besb way to geb a view of thtra is to let tha leaf dry up. This causes them to come out of their galleries, and they may bo obFerved wandering about in great numbers, or huddled together in some cranny of the leaf. "There is good evidence that the mites hibernate in tho buds and in galleriea on the new wcod, they having been discovered in the buds in the winter time ; and, having beeu seen to attack the leaves of the bursting bnd in spring, very likely the egg* are deposited in the buds. Thtse points, however, need further observations." The above is txiclly what I have myself many time 3 noted ; the mites winter over in the buds, and I have some now iv which mites have already taken shelter. I have counted as many as 302 mites under one scab, but the avernge, so far as my observations go, is about 200. Leaves from the warmer parts of the colony appear to contain more than tho3e from the south. The mites come from their galleries on the surface moro freely in warm dry days than at any other time. The groat damage done by these mites may not at first be apparent, but ib must be rememberod that the wholo of the attacked foliage is rendered unhealthy and distorted, resulting in the premature fall of the leaf, and this in turn c.iuses unhealthy trees and a consequent ehoit and imperfectly develop 3d crop of fruit. Treatment. — Rake up and burn all foliage from fruib trees. This will dispose of many insects besides the mites, also myriads of fungus spores, thu3 preventing tho spread of disease next season. After ths leaves have dropped, spray thoroughly with kerosene emulsion ; repeat just before the buds burst. _ The above I hay.3 found usually quite effectual, bub, should another dressing be deemed necessary, spray again jusfc atter the petals fall.