MISCELLANEOUS. 



61 



The variation in the amount of cyanide depends to some extent 

 on the character of the plants that are being treated, on their strength, 

 whether they are dormant or active, evergreen or deciduous, and also 

 on the season. In the case of tender plants, i oz. of cyanide may 

 serve for 500 cubic feet of space, while hardy plants may be treated 

 with i oz. of cyanide to 200 cubic feet of space." 



Hitherto I have always used and recommended the following 

 formula 1 : 2 oz. cyanide, 4 oz. acid, and 7 oz. water to every 1,000 

 cubic feet of space, and I have invariably found it satisfactory. Had 

 anything like the quantities recommended by Mr. Froggatt been 

 employed, the results would have been disastrous. 



In this connection I may perhaps cite a series of little known, but 

 very interesting experiments made by Mr. H. H. Cousins. 2 



The first three experiments were made on vineries, which were 

 suffering from a severe attack of Mealy Bug. The particulars are as 

 follows : 



The results obtained were as follows : 



A. The Mealy Bug was destroyed and the foliage unhurt, but 

 three quarters of the bloom was injured. A few Mealy Bugs appeared 

 at the close of the season, and a second fumigation was decided 

 upon, which, so late as the following April, was described as com- 

 pletely satisfactory. The vines were in full bloom and the fumiga- 

 tions given after sunset. 



B. Here the Mealy Bugs were destroyed without any injury to 

 the vines. A few appeared in the autumn, and a second fumigation 

 was given, with the same success as in the previous case. The first 

 fumigation was given before the vines bloomed and after sunset. 



X 2nd Report on Inj. Insects, 1905, p. 62. 

 2 Journ. S.-E. Agric. Coll., 1895, pp. 67-70. 



