1921\] Prevention of " Bunt " in Wheat. 1021 



which have been soaked in the formalin solution; the sacks 

 should be uniformly wet but not dripping. 



(4) The treated seed is left covered up for 4 hours, then 

 spread out to dry on a clean floor ; if the floor has been previously 

 used for untreated corn it should be wetted all over with the 

 formalin solution and allowed to dry before the treated seed is 

 spread on it. 



(5) Precautions should be taken to prevent the re-infection of 

 the treated seed, e.g., sacks which have held untreated infected 

 wheat should not be used for the treated seed, unless they have 

 undergone treatment by being soaked in the formalin solution or 

 boiled in water. 



Summary. — 1. There is reason to believe that the common 

 practice of " pickling " seed wheat with a 10 per cent, solution 

 of copper sulphate (1 lb. to 1 gal. water) as a preventive against 

 " bunt " results in serious damage to the germination of the 

 seed.* 



2. Experiments carried out at Wye College on wheat of the 

 " Ked Standard " variety grown on duplicate plots during two 

 seasons have shown that : — 



(a) Formalin 1 : 240 solution or 1 pint to 30 gal. water, 

 when sprinkled over the seed, w T hich is then covered by sacks 

 soaked in the same solution for 4 hours before being spread 

 out to dry, completely controls " bunt " in wheat. 



(b) A 2.5 per cent, solution of copper sulphate (2 J lb. to 

 10 gal. water) reduces the amount of infection considerably 

 but is less effective than the formalin solution. 



(c) A 1 per cent, solution of copper sulphate (1 lb. copper 

 sulphate to 10 gal. water) also reduces the amount of infection, 

 but is far less effective than either the formalin solution or 

 the 2.5 per cent, solution of copper sulphate. 



3. Formalin, 1 : 320 solution or 1 pint to 40 gal. water, has 

 proved to be as effective in controlling the disease as the stronger 

 (1 : 240) solution, and is therefore to be preferred. 



4. The quantity of solution necessary to wet thoroughly 4 

 bushels fa sack) of wheat has been found to be 2 gal. 



5. The formalin solutions at the above strengths and also 

 the 2.5 per cent, solution of copper sulphate show a tendency 

 to reduce slightly the percentage of germinating seeds, so that 

 treated seed should be sown a little thicker than normal. 



° For this reason the Ministry of Agriculture in its Leaflet No. 92 

 recommend a weaker solution even though it is known that with this solution 

 the control of bunt is not so complete. — Editor Journal. 



C 



