1016 



Prevention of " Bunt " in Wheat. 



[Feb., 



to the Ministry's Seed Testing Station for germination tests. 

 The untreated sample germinated 98 per cent, in four days. The 

 treated sample germinated only 47 per cent, in ten days; after 

 15 days it gave 57 per cent, and finally reached 60 per cent. 



The extremely injurious effects, viz., the killing of a con- 

 siderable percentage of the seeds and general retardation of the 

 germination which is caused by a 10 per cent, solution of copper 

 sulphate makes the latter, in the authors' opinion, far too 

 dangerous a remedy for use against " bunt." This strength of 

 solution, however, is at present commonly employed in England.* 

 It is to be feared that many cases of a " poor plant " in wheat 

 may have been caused by the seed having been " pickled " with 

 too strong a solution of copper sulphate. 



In preliminary germination tests carried out at Wye College 

 it was found that a 10 per cent, solution of copper sulphate 

 sprinkled over seed wheat so as to wet all the grains, reduced 

 the vitality of the seeds to such an extent as to render the treat- 

 ment impracticable. Solutions containing copper sulphate at 

 concentrations of 5 per cent., 3.5 per cent., and 2.5 per cent, 

 were then tried, samples being sent to the Ministry's Seed 

 Testing Station for germination tests. The report received was 



It was finally decided not to employ copper sulphate at a 

 concentration higher than 2.5 per cent, in the experiments 

 described below. 



Another chemical substance, however, viz., formalin t pos- 

 sesses equally fungicidal properties against " bunt," and it is 

 the object of this article to show that this substance, not at 

 present used by farmers in this country for the prevention of 

 " bunt," is well worthy of trial, since in the two years' field 

 experiments described below, its use has been attended with 

 satisfactory results. + 



• eq., in Kent, Sussex, Surrey, Berkshire and Herts. 



f Formalin is the trade name for a 40 per cent, solution of the gas formal- 

 dehyde in water. 



% In an article on the prevention of "Covered Smut" of barley (see this 

 Journal, March, 1 918, XXIV) the writers have shown that treatment of the 

 seed with formalin gives complete protection against this disease, while the 

 result of treatment with a 2-5 per cent, solution of copper sulphate was 

 »uch inferior. 



as follows : — 



Percentage of 

 Germination. 



Method of Treatment. 



5 per cent, copper sulphate 



80 

 86 

 88 

 95 



