46 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Season 1917. 



In commencing the 1917 season's experiments we decided to put 

 down plots' on a larger scale and make the attempt to exterminate 

 the disease throughout the nursery. Three houses were treated with 

 mercury chloride solution wherever disease remained, one house with 

 sodium cyanide (for potassium cyanide was not procurable), four 

 houses with liquid carbolic acid, two with creosote emulsion, one 

 with a liquid, called Twiset, which had been kindly presented to us, 

 and one with pyridine. Of the vermicidal power of the last two 

 we knew nothing. 



Table XV. — Substances Used on Plots in Season 1917, 

 with Quantities and Costs per Acre. 



Plots. 



73, 74 

 63, 64 



25, 26, 27, 28 

 53, 66, 72, 55, 

 65,20,19,54, 

 7 1 , 56,67 



62 

 476 



34, 35, 36, 37, 

 42, 43,4!, 39 

 44, 45 



32, 69, 68, 70 

 57, 58a, 58b, 



59, 60 

 17, 5i, 14 

 5°, 48, 9, 7, 6 , 



5, 3, 4 



Substance Applied. 



Mercury bichloride 

 ,» 

 ,» 



j- Sodium cyanide 

 Cresylic acid 



} : 



Creosote emulsion 



Pyridine 

 1 Twiset 



Quantity 

 per acre. 



Dilution. 



Price. 



Cost 

 per 

 acre. 







1/500 







£ 



1*2 



cwt. 



35. 



per lb. 



20 



3 



,, 



1/500 



35. 



1, 



5° 



3 



,, 



1/500 



3S. 



,, 



50 



24 



,, 



l/l5° 



IS. 



per lb. 



135 



427 



gal. 



l/8o 



35. 



per gali. 



64 



4*5 



,, 



l/8o 



35- 





62 



465 



,, 



I/80 



35. 



it 



70 



385 





l/8o 



35. 



,, 



58 



S70 





1/45 



IS. 





43 



700 



,, 



i/45 



IS. 



, , 



35 



16 



cwt. 



1/100 



2S. 



6d. „ 



20 



165 



gal. 



1/100 









All plots which were supposed to be cured were left untreated. 

 Of these certain plots had shown no disease since the first treatment, 

 their history being epitomized in Table XVI. 



Table XVI. 



Plot. 



Application. 



1915. 



1916. 



1917. 



I 



Nitric acid 



X 



0 



0 



8 



Potassium permanganate 



X 



0 



0 



1 1 



Kainit 



X 



0 



0 



21 



Chromic acid 



XX 



0 



0 



22 



Potassium bichromate 



XX 



0 



0 



23 



Mercury bichloride 



xxxx 



0 



0 



24 



Potassium cyanide 



XXX 



0 



0 



29 



Mercury bichloride 



XXX 



0 



0 



3i 



Phenol 



X 



0 



0 



46 



Kainit and caustic soda 



X 



0 



0 



