1921.] Prevention of " Bunt " in Wheat. 



1017 



Field Experiments in 1919. — The seed used in these experi- 

 ments was obtained from the crop of " Red Standard " wheat 

 found to be severely attacked by ' ' bunt ' ' during the summer of 

 1918 (see p. 1013). Four samples of this wheat were taken; one 

 sample was left untreated for the control plots and the others 

 treated as follows : — 



(1) One per cent. Solution of Conner Sulphate. — Commercial 

 copper sulphate (98-99 per cent, purity) was dissolved in water,* 

 so as to make a one per cent, solution (i.e., at the rate of 1 lb. 

 to 10 gal.) which was sprinkled over the seed and well stirred in 

 until all the grains were wetted; the seed was then spread out 

 to dry. 



It was found that the volume of solution necessary to wet the 

 grains thoroughly was 1 part to 16 parts of the seed, i.e., at the 

 rate of 1 gal. of the solution to 2 bush, of the wheat, and the 

 solutions used in all the experiments described below have been 

 applied at this rate. 



(2) Tico and a half per cent. Copper Sulphate. — This solution, 

 prepared at the rate of 2 J lb. copper sulphate in 10 gal. of water 

 was applied in the same manner as the one per cent, solution. 



(3) Formalin 1 : 240. — One part of formalin (40 per cent, 

 formaldehyde) was added to 240 parts of water (i.e., at the rate 

 of 1 pint to 30 gal., or, for small quantities, 1 fluid oz. to 1J gal.) 

 and stirred in until the formalin was uniformly distributed. The 

 solution was then applied in the same manner as the copper 

 sulphate solution, but instead of immediately spreading out the 

 wetted corn to dry, it was placed in a heap and covered over with 

 sacking which had been soaked in formalin solution of the same 

 strength as that sprinkled over the corn. After four hours the 

 wheat was uncovered and spread out to dry. 



The seed was treated on 16th November, 1918. dried over- 

 night, and on the following day the four samples were sown 

 broadcast at the rate of about 3 J bushels to the acre, on dupli- 

 cated plots, each measuring 40 ft. by 10 ft. The plots were 

 numbered as follows : — 



Plots 1 and 5 seed treated with 1 per cent, copper sulphate. 

 , 2 „ 6 „ „ „ 2-5 „ , 

 ,, 3 7 ,, „ „ formalin 1:240. 

 ,, 4 ,, 8 ,, untreated. 



Samples of the treated and untreated seed were sent to the 

 Seed Testing Station in order to have determined the effect of 



* In dissolving copper sulphate in water, a wooden or earthenware re- 

 ceptacle must be used, not metal. 



