354 DESTRUCTION OF CHARLOCK. 

cent. solution. Plot. III., 25 gallons per acre of a 4 per 
cent. solution. 
The spraying was carried out by two members of the 
college staff, and each centre was visited at intervals on 
three different occasions. The dressings were applied at two 
of the centres on May 23rd., and at the third centre on 
June 6th. 
It appears that none of the solutions employed in these 
experiments were entirely successful at any centre, for all 
failed to destroy the charlock. On Plots I. and II., which 
received 50 gallons per acre of a 2 per cent. and of a 3 per 
cent. solution respectively of sulphate of copper, the dressings 
destroyed a large proportion of the weed, possibly about 
60 per cent. of it, at two of the centres, and checked the 
growth of the remainder, the 3 per cent. solution being most 
effective. The results obtained on Plot III. showed that 
even when a strong solution is used, it must be applied in 
greater quantity than 25 gallons per acre if it is to be 
successful. 
The results are reported to have been, on the whole, rather 
disappointing. Although the conditions were very favour- 
able at two of the centres, the dressings were only partially 
effective. In experiments conducted in 1899, 50 gallons of a 
2 per cent solution of sulphate of copper give the best results, 
but only succeeded in destroying part of the charlock. In 
1900 the results were very similar. Where the wild turnip 
occurred the results were the same as in 1899, further tending 
to prove that the charlock plants are attacked because the 
dressings adhere to their rough leaves, whereas the smooth- 
leaved plants are but little affected. The corn at the 
different centres was discoloured more than was the case 
last year, but at no centre did the crop appear to ultimately 
suffer. The grass and clover seeds growing in the corn a; 
two of the centres were also unaffected by the dressings ; 
indeed, at one place they appeared to have been improved. 
But although the results were not so favourable as some 
obtained elsewhere, it is claimed that they show that the 
operation is one which wili do much more than repay the 
outlay, and justify the belief that if the spraying be carried 
out for a number of years the charlock will ultimately be 
got rid of. 
