FjAFPERTY — Disease of Cultivated Flax. 



269 



Steeping in the stronger solution satisfactorily disinfected the seed, but 

 retarded and seriously reduced its percentage of germination. Steeping for 

 ten minutes in the weaker solution killed the fungus, and did not reduce the 

 germination of the seed, while steeping for five minutes only in this solution 

 did not kill the fungus. 



A repetition of the experiments gave similar results, with the exception 

 that steeping for ten minutes in the 0'09 per cent, solution did not kill all 

 the conidia ; a few were found still viable after treatment. 



Owing to the sticking together of the steeped seeds, however, it was found 

 difficult to treat a quantity sufficient for sowing purposes. Hence no plots 

 were laid down with seed steeped in formaldehyde solution. 



Formaldehyde Solution: SjJraying. — In order to avoid, if possible, the 

 disadvantages of steeping, attempts were made to disinfect ilax seeds by 

 spraying. Lots of half a pound each of affected seed, after having been spread 

 out in thin layers, were sprayed by means of an atomiser with 20 c.c. of 

 diluted formaldehyde solutions of varying concentrations. This amount of 

 liquid was not sufficient to cause the seed to become mucilaginous. After 

 atomising, the seed was dried for twenty-four hours at 40°C. It was then 

 tested for germination, and the viability of the conidia present on the seed 

 was also tested. The results are summarized in the following table : — 



It will be seen that a concentration of 0-59 per cent, of formaldehyde was 

 required in order to kill all the conidia, but the germination of the seed so 

 treated was considerably reduced. Higher concentrations had a more pro- 

 nouncedly deleterious effect on the germination of the seed, while lower ones 

 did not entirely kill the conidia. . 



