REPORT OF THE HORTICULTURIST. 



101 



tion. My report of 1891 on spraying shows the value of adding Paris green 

 to the solutions of ammoniacal copper, but no exact figures have been gathered 

 showing the effect of adding lime. Exact data will be obtained on this point as 

 soon as possible. With regard to small fruits, Mr. Tweddle says " some encouraging 

 results came from the use of Bordeaux mixture and Paris green for the destruction 

 of the currant worm, and for the prevention of mildew on gooseberries — some of 

 them English varieties. The first brood of the larvse appeared in myriads on the 

 currant bushes shortly after fruit set. A single application of the above was made 

 soon after the worms were hatched when ^ inch in length, but not all were 

 destroyed. When in two or three days, but before the worms were large enough to 

 devour the foliage rapidly, two more applications were made on the same day, going 

 ojDposite directions on the rows and completely covering the foliage. This was 

 entirely successful in destroying the first brood, and also the second, for the lime in 

 the Bordeaux mixture stuck the whole thing to the foliage so well that it remained 

 all season, and if any of the second brood were hatched, they immediately received 

 their dose and vanished." He says further : '* No mildew or sunscald appeared on 

 the English gooseberries (although none even were left unsprayed as checks on my 

 place), yet both mildew and sunscald affected my neighbour's plantation alongside 

 under similar conditions, where no fungicide was applied." It is hoped that the 

 experience gained as the result of another season's work will clear up some points 

 which at present appear contradictory and unsatisfactory. 



EFFECTS OF DILUTE SULPHURIC ACID ON FOLIAGE. 



The use of sulphuric acid has been suggested by prominent horticulturists on 

 the grounds that it contains the essential elements of a fungicide, and being prepared 

 by simple dilution would therefore be more easily applied than the copper salts. 



Some preliminary experiments were inaugurated this season in order to ascer- 

 tain the maximum strength at which it could be safely applied to the foliage of 

 various plants. 



The information obtained is embodied in the following tabular statement: — 



Plants Treated. 



Grapes . 

 Plu:iis.. 

 Apples . 



O C 



a 



June 5. 

 do 5. 

 do 5. 



'Rose foliage,]Mar. 14. 

 mature. 



Rose foliage, 

 young. 



c J 



Strawberry . 

 Geranium .. 

 Hibiscus. . 



do 



do 

 do 

 do 



I per cent. 



Injured. . . 



do .. 



do .. 

 No injury 



do 



do 



do 



Slight in- 

 jury. 



Strength by WEroHT. 



i per cent. 



1 per cent, l^ per cent. 



Badly in- 

 jured. 



Injured. 



No injury . 



Slightly in- 

 jured, 

 do 



Injured. 



Consid'rably 

 injured. 



Slightly in- 

 jured. 



Badly in- 

 jured. 



Badly injured. 



Considerably 

 injured. 



Remarks. 



Badly burned and 



shrivelled. 

 Injury severe. 



Burned in spots. 



Injury gradually in- 

 creased. 



Half -grown leaves 

 uninjured. 



Badly injured. Young as well as old 

 leaves injured. 



Badly injured. 



Scorched in spots. 



The injury to the foliage in every case appeared to be duo to the concentration 

 of the sulphuric acid by the evaporation of the water used as the dilutent. 



The rate of evaporation would of course be largely governed by the humidity of 

 the atmosphere and would be relatively slower under greenhouse conditions than 



