IRISH GARDENING. 



93 



together the average yearly increase of sound 

 tubers in the main crop varieties is between two 

 and three tons per acre, or from 20 to 30 per cent. 

 The custom of spraying with copper sulpliate 

 solutions having originated in France the com- 

 pound of copper sulphate and lime is known as 

 "Bordeaux mixture," and that of copper sulphate 

 and washing soda as " Burgundy mixture " ; 

 both are thoroughly efficient fungicides. 



The common practice adopted on all up-to-date 

 Potato farms is to spray as early as possible ; 

 that is, as soon as possible after the haulm has 

 recovered from the final earthing up of the Potato 

 ridges. Then to spray again, and yet again, if the 

 weather and growth permits, the third spraying- 

 being as late as some time in August with the 

 main crop varieties. The apparent injury done to 

 the hauhn and soil by the passage of the horses 

 and machine wheels is more than recompensed by 

 the additional crop secured by this treatment. 

 • The continual practice of spraying has graduallv 

 brought an important feature to light, and one 

 which, owing to the advance in the price of 

 cliemicals, is of importance, and that is that 

 solution known as one per cent, solution, namely, 

 one pound of copper sulphate to 10 gallons of 

 water (equal to 1001b. water), are practically as 

 effective as the two per cent, solutions commonly 

 used, but this specially small quantity of suli^hate 

 of copper must be dissolved even more thoroughly 

 than ever, and is another argument to use only 

 the best and most easily dissolved preparation. 

 Some Warnings. — As there are other diseases 

 of the Potato plant besides that known as the 

 " blight " an illustration is given of the pre- 

 liminary signs of " blight *' as shown on the 

 Potato leaf taken from the illustration sent with 

 their pamphlet on " Potato Disease," by the Food 

 Production Department of the Board of Agricul- 

 ture and Fisheries, and it should be pointed out 

 that spraying is not a preventive of other 

 Potato diseases. 



Spraying shovild never be done on mornings in 

 summer when frost is present, nor late in the 

 afternoon when a frosty nightjis threatened, nor 

 in a hot period when the Potato plant is stunted 

 and suffering from drought. 



It is not advisable to spray plants on plots 

 situated in an atmosphere containing acid fumes, 

 or those attacked by aphis, and it is necessary to 

 be very careful to use the right proportions of the 

 ingredients in making your own mixture, and to 

 use only the purest obtainable. 



As one who carried out some of the earliest field 

 experiments in this country on the Potato crop 

 with the Knapsack sprayer for the Royal Agricul- 

 tural Society of England, and who subsequently 

 used the very first horse-spraying machine (made 

 by Mr. G. F. Strawson) on some hundreds of acres 

 of Potatoes, and later conducted the first field 

 experiments against charlock, the writer cannot 

 too strongly advise those who do not purchase 

 some well-known standard proprietary mixture 

 to purchase for their own mixing only the very 

 purest and best raw materials, whether sulphate 

 of copper, lime, or soda. In all one's experience of 

 spraying, and in the early days we had to do our 

 own mixing of copper svilphate with lime — soda 

 was not used then — there was only one satis- 

 factoryj^source of linie, and that was fi'om Buxton, 

 and to attempt to use other lime meant trovible 

 both with the solution and the machine. Again 



there were delays from all sources, difficulties in , 

 getting ordinary commercial svUphate of copper 

 to dissolve, and also to obtain the right proportion 

 of lime to soluble sulphate of copper — a most 

 important point on which the success or failure of 

 the operation of spraying entirely depends ; again, 

 the sulphate frequently contains iron sulphate, 

 which may prove injurious, and is lumpy, whereas 

 it should be in the form of a powder and thus 

 dissolve readily in cold water. 



Our enterprising manufacturers are fully alive 

 to the necessity of the times and acquainted with 

 the best treatments suitable to all crops in this 

 country, and as their businesses are dependent 

 upon good results their recommendation and 

 goods may be relied upon Avith every confidence. 

 As these firms specialise in sprays, they use only 

 the best and most soluble sulphate of copper and 

 washing soda, or the purest and finest lime, and 

 in all cases they give directions as to the propor- 

 tions and use of their goods. 



Special Spraying Machinery. — The require- 

 ments of a first-class Potato spraying machine, 

 whether in the form of a Knapsack or horse-driven, 

 are to produce the finest spray with the greatest 

 force so as to cover the foliage most searchingly 

 with a fine spray which will dry quickest upon the 

 surface of the leaf and not run off and waste or 

 wash off easily. This means that the two most 

 essential points in a machine are a strong punip 

 and a suitable nozzle, and in the case of the 

 Bordeaux mixture, that is, copper sulphate and 

 lime, there should be a good agitator to keep the 

 lime in suspension. 



The finer the spray the more it economises the 

 quantity of fluid required to spray, and the more 

 effectively is the work done. This should prove 

 conclusively that the best machine is almost 

 invariably the cheapest in the long run. The spray 

 should be directed upwards from a low level, so 

 as to catch the underside of the leaf, where it is 

 better protected from the rain, but as both 

 surfaces of the leaf are liable to infection the upper 

 surface should also receive its share, and this 

 occurs when a good sprayer is used. 



Remember it is an expensive mistake to apply 

 too much fluid ; all that is required is that after 

 spraying the thinnest possible covering of the 

 fungicide should be spread evenly on the leaves, 

 and this is best done by maintaining a high 

 pressure in the spraying machine. 



The hugely increased acreage of Potatoes and 

 the vital necessity of producing a large crop of 

 sound tubers, which by Government action are 

 assured a good price, have brought a multitude 

 of new growers into the business who have little 

 or no equipment for spraying, and the demand 

 upon the makers of sprays and sprayers is, even 

 at this early date, a noteworthy feature ; pre- 

 sently it will be ahnost overwhelming. The Food 

 Production Department state that " It is essential 

 that all those who are not already provided with 

 Knapsack spraying machines shall place their 

 orders without delay, that the prices of copper sul 

 phate in 1918 will be controlled in such a way that 

 purchasers ordering for early delivery in the year 

 will have a distinct advantage over those ordering 

 later, and that there will be a shortage of soda 

 crystals in the coming season. Hence it is 

 absolutely essential that early steps be taken to 

 ensure the necessary supply for spraying pur- 

 poses." — Modern Farming, May, 1918. 



