1020 



Prevention of " Bunt " in Wheat. 



[Feb., 



can be drawn on this point.* As the plants approached maturity 

 the difference was not maintained, and when harvested the crops 

 were equally vigorous apart from the plants infected with 

 " bunt." 



In August, 1920, bundles of plants were pulled from each plot 

 and the number of ' ' bunted ' ' ears determined as in the previous 

 year. Five bundles, however, were taken from each plot so that 

 for each method of treatment 1,000 ears were examined. The 

 results are shown in the table : — 



Plot. Method of No. of Bunted No. of Bunted Percentage 



Treatment. Ears in : 



1 Copper sulphate 1 per cent. 29 ) 

 « „ „ „ » 42 J 



2 Copper sulphate 25 per cent. 12 ) 



7 „ m » h 10 > 



3 Formalin 1 :240 j 

 S 2 5 



4 Formalin 1 :320 ) 



9 ■ i) 



5 Untreated 117 ) 



10 „ 202 S 

 The only precautionary measures adopted at the time of sowing 



to prevent re-ihfection of the treated seed by spores from the 

 untreated seed, consisted in sowing the former and raking it in 

 before the latter was sown. Considering the fact that all the 

 plots were sown on the same morning, and that the two formalin 

 plots in which 1 and 2 " bunted " ears, respectively, were found, 

 adjoined the control plots, the extremely low number of cases of 

 infection on the formalin plots is remarkable. The results 

 obtained show that the formalin treatment as employed in these 

 experiments is completely effective in controlling " bunt " in 

 wheat. 



As the formalin treatment is not generally practised in this 

 country the following notes on its use, based on the experiments 

 recorded above, may be useful : — 



(1) The diluted solution recommended for use is prepared by 

 adding one part of formalin (40 per cent, formaldehyde) to 320 

 parts of water (e.g., one pint formalin to 40 gal. of water, or, 

 for small quantities, 1 fluid oz. to 2 gal.). 



(2) This is slowly sprinkled over the seed wheat at the rate of 

 1 gal. of solution to 2 bushels of seed; the seed is moved about 

 and stirred until the grains are thoroughly w r etted.t 



<3) The seed is then placed in a heap and covered with sacks 



• Fitdd Trials using formalin at lower concentrations ar« in progress, 

 f Under no circumstances mnst the solution be allowed to form pools 

 under the heap in which grains might soak. 



500. Ears in 1000. Bunted. 



71 7-1 



22 22 



2 0-2 



1 0-1 



319 319 



