.10 May. 1912.] ]]'//{■(!/ and its Ciilfivaiioii. 271 



higher plants. This smut fungus is parasitic in its growth, and attacks the 

 A\heat plant just when germination takes place. The mycelium of the 

 fungus then penetrates the wheat plant, lives on its host, grows with it, 

 .and ultimately produces myriads of spores which collectively form the 

 " bunt balls'" of the infected heads. The effect of the fungicides, used 

 in pickling, is to kill all the spores in any wav adhering to the grain. 



Most of the spores adhering to infected grains will be found in the 

 ^' brush "■ of the kernel, whilst a lesser number are usually found in the 

 •crease of the grain. If a number of grains of wheat be poured into a 

 vessel of water, it will be noted that small bubbles of air invariably be- 

 come entangled in the tuft of hairs constituting the '.' brush,'' and in such 

 cases the grain does not become moistened at these points, even after pro- 

 longed immersion. This will explain the need for vigorous agitation of 

 the seed whilst immersed in the pickling solution. 



Reinfection may, and often does, take place after the seed has been 

 p'ckled. This commonly occurs where the pickled .seed has been trans- 

 ferred to smutty bags which have not bt«n treated with the pickling solu- 

 tion. Again, in sowing the seed the bunt balls, left among the grain 

 by careless pickling, may be broken in the drill, and the contents of the 

 ball scattered o\er the seed. It must, of course, be borne in mind that 

 while loo.se bunt spores are killed by contact with the pickling solution, 

 the spores contained within the unbroken bunt balls, which float on the 

 surface of the pickle, are unaffacted by the fungicide. Steps must, there- 

 fore, be taken during pickling to remove or break any bunt balls which 

 may be present in the seed. 



An ideal fungicide for pickling purposes would require to be {a) 

 cheap; (b) efective, i.e., capable of destroying all the spores adhering 

 to the grain ; {c) capable of preventing reinfection of the seed ; {d) with- 

 out effect on the gerinination of the grain. The fact that so much con- 

 troversy has arisen respecting the various fungicides on the market is 

 proof that the ideal fungicide has not yet been obtained. 



Bliiestone is a most popular fungicide, and, when properly used, is 

 verv eft"ecti\e. 



The stronger solutions have a very deleterious effect on the germination 

 of the grain, as they not only reduce the germinable power of the seeds, 

 but also delay the germination considerably. Manv instances were observed 

 last season by the writer when judging farm crops and farm competitions, 

 in which crops were badly affected with bunt, although the seed had been 

 pickled with bluestone. In all these cases, however, the cause was un- 

 doubtedly the arbitrary method of pickling adopted. Instead of using a 

 solution of fixed and definite concentration, the practice followed w^as that 

 of dissolving a handful of bluestone in a small but unknown quantity of 

 water and pouring it over a bag of seed. Such a method of procedure 

 is most unsatisfactory, ^^'hat the grower needs to realize is that the strength 

 or concentration of the solution is all important to successful work, for 

 there is an optimum concentration at which the best results are obtained. 

 Below this strength the fungicide is ineffectual, and with higher concen- 

 trations the germinat'on of the seed is greatly interfered with. 



In practice the amount of bluestone which gives the best results is 

 i| lbs. 'to 10 gallons of water, i.e., i| per cent. Of course, smutty seed 

 may require as much as 2 lbs. to 10 gallons, but the farmer should make 

 it his business not to sow dirty seed. He should make it an habitual prac- 

 tice to reserve each j^ear the very cleanest and best-grown portion of his 

 crop for next season's .seed. 



Various substances ha^e been used to lessen the corrosive action of 

 the bluestone, and among these the u.se of lime and salt have been 



/ 



