LEAFLETS FOR GARDENERS AND FRUITGROWERS.

Otago Witness, Issue 2309, 2 June 1898, Page 8

LEAFLETS FOR GARDENERS AND FRUITGROWERS.

No. 23. — Plum Rust (Puocinia prani). By T. W. Kirk, P.L.8., &o. } London, Govern"ment Biologisfe. This disease attacks quite a number of slone fruits, causing fche leaves to fall prematurely,

Upper aad under sides of plum leaves, showing at>«i ihe tree being defoliated, the crop na tarsi! j 1 suffers evso it it is »ot quite loaf?. The rust firsS appears on tha upper side of the leaf in the form of yellowish or browc, sometimes reddish-brown, spots ; on the u-ndev side these spots are usually brown or' black, sometimes with a yellowish tinge. Iv advanced stages — i.e.i when the fungus has developed — ■ ; the surface as%umes the true rusty appearance, and looks as though coyered with brown or black powder. Very coosiderablc loss is caused by rusS. With this, as with all fungas diseases, the treatmentTsliould be preventive — viz., prune in autumn, taking case to rako up and burn all prunings, and as far as possible all fallen leaves. Then, juet before the bads burst, spr&y with ! Bordeaux mixture, full etrongth. As sooif as 5 the petals have fallen in spring spray with j ammonia catbonate of copper solution, or, if not at hand, with Bordeaux mixture diluted to 60gal fetrength ; and again three or four werks later with the lasl-named mixture. The directions foe making these mixtures are : FUNGICIDES, ETC. Bordeaux Mix!;ure, an Excellent Standard Formula, Convenient for Reducing to anyRequired Strength. Take fulpbate of copper (perfectly pure), ! 61b ; fresh unslaked lime, 4!b ; water, 22gal. I Pi&ce the sulphate of copper in a piec% of sack- ; ii.g ov any light* cloth. Suspend it by a string from the toy of the barrel, a few inches bslpw the surface of the w&ter, to dissolve, using 18gal of water. Ttien slake in & wooden tub 41!» of perfectly fresh lime in as small a quantity cf. water aa possible, adding the water little by lifctla — never enough to corer the lwmgs — until slaking has been completed, when slowly make up to4gal. When osol, thoroughly stir and strain glowiy the aiilk ot lime into the poppet solution, stirring thoroughly when caix- ; ing »»d for aa additional minute or fcwo, when ifc is ready for ute as s winter spray, aad is Called a 22gai mixture. By adding the requisite quantity of water, at the same time observing to keep the mixture thoroughly stirred, ib can be diluted to a 30gaJ, 50gal, or 60*ai mixture for spring and summer use. : ; 1% is important to obsesve the method of combjning the ingrt Joints ; also, .that the qwppec should pc pure, ?.'. thufc, unslaked lime should be used, not air .slaked. It is further important to note thau in order to obtain the best results the mlxtutp should bo applied within eight hours from the time it is prepared, 01 afc rcosc 22 hours, owing to a complex chemical < change which takes pl»ce. I In the application of Bordeaux mixture a I general lino of treatment to be recommended is : { j-During winter, or before the buds sfcarfc in j spring, spray all the frnifc trees with the 22gal strength ; again, just ad the pet&ls drop, with the 60gal mixture. - If Bordeaux mixture is made and applied as above it adheres teueciou3ly to the wood and foliage ; there seems no need foi the addition 1 of treacle. I Stock Solution, Bordeaux Mixture. Owing to ordinary Bordeaux mixture requiring to be used at least, within 24 hours from j the time it is made, stock solutions are now : prepared ready for mixing of both milk of Jime and sulphate of copper. Thib is found a great convenience for use in largo orchards. These stock solutions are prepared na follows : Eksfcly, by dissolving in a barrel 1001b of sulphate ot" copper U> 50gttl water by exact measurement, go that each gallon will hold in solution 2lh of eopper-dulphafce ; secondly, a slock solution of Edlk o? lime is prepared b"y dissolving slowly in water 100!b of fresh stone lime, to be made up to 50gal, so thfct esch gallon of the solution will contain 21b of lime. This solution cf milk of ' [ lime, if kept airtight, will remain fit for uee for j 1 } several d&?B. After about fehe fifth day it [ : would !'ft better to make freah. j ; In preparing Bordeaux mixture from the : stock preparation^ Zvi'i take 3gal from the J 1 stock solution ox. sulphide of copper, and add to 1 17 gal water in a barrel. Second, from the ! afeoek solution of milk of lime, after thoroughly 1 stirring, take 2gal, more or lesß, and pour • elowly into the sulphate of copper solution placed in the barrel, all the time stirring aud ■ carefully watcliipg the colour ; when a clear | i j sky-blue colour shows, immediately stop adding ' ' the milk of lima. It ia tketi cefcdv tor use, The

foregoing may be considered a 22gal formula. For a 30gal formula add additional 8g»l water, or for a 60gal formula add 38gal water, «»cirriog thoroughly all the tinm.

Carbonate of Copper Solution.

Procure a tub or barrel, and in this dissolve 61b of copper sulphate or blnesfcone 5d 4g».J or sgal of water. la another vessel dissolve 7ib of washing or 3al soda, using hot water for the purpose. When the solution is cool pour ii slowly into the vessel coatainitsg the copppr sulphate 'liquid, at ir the mixture thoroughly, then allow it to stand 24- hoars. Now syphon off the clear liquid, and allow tbe sediment, which is carbonate of copper, to stand for a day or two until it becomes pasty. For every 7oz of this paste add three pints of strong ammonia water (which may be bought of any chtmisfc), or enough to dissolve the sediment. Tha liquid thus obtained is concsntr&tsd ammoniacal solution. To prep ire ib for spraying it is only necessary to dilute each three pints with 45gal of water.

In order to avoid stuning the fruit, etc.. do not use more strong ammonia than is absolutely necessary to dissolve the carbonate of copper. A valuablft fungicide.

The powder oT carbonate of copper can now be purchased from tha New Zealand Drug Company," or the ammoniacal carbonate of capper solution put up in bottles with instructions ready for diluting to standard strength. To prepare the powder of carbonate of copper for u=ie, firs'-; make into a thin paste by adding a pint and a-half of water, then add slowly three pints of strong aqua ammonia, and thoroughly stir until a clear, deep -solution is obtained, when dilute with water" to 4-sgal.