BY D. McALPINE. 451 



parasitic fungi and the utility of such knowledge to the grower, 

 I cannot do better than quote from a letter recently received from 

 Mr. George Quinn, Inspector under " The Vine, Fruit and 

 Vegetable Protection Act," South Australia. He writes (May 

 28th, 1895) : — " The disease {Pvccima pruni) has been very preva- 

 lent in our orchards in all parts of the Colony in the season just 

 closing, and I am somewhat in doubt as to how its spores exist 

 over the winter, for in orchards where the peach or plum trees 

 have been thoroughly sprayed with Bordeaux Mixture, with 

 excellent results, as far as the 'curl leaf is concerned on the 

 former, and I am perplexed as to where the S23ores find refuge 

 until the autumn when the pustules begin to show on the foliage 

 of the trees. Do you think it possible for the spores which have 

 fallen either before or with the diseased leaves to be ploughed 

 into the soil and then be turned up again with the summer 

 cultivator to rise with the dust among the foliage, and, the condi- 

 tions being suitable, germinate ? Do you think the spores of the 

 various parasitic fungi which injure our fruits would lose their 

 vitality completely if ploughed beneath the soil for a winter ? 

 Would they not keep, like the seeds of some more highly organized 

 vegetables, for a considerable time T 



To answer the above question, I am testing during the forth- 

 coming season, 1st, if the uredospores retain their vitality and 

 germinating pov/er during the winter, both when lying on the 

 surface of the ground and when buried to a depth of four or five 

 inches; 2nd, at what time teleutospores are capable of germination 

 and how they are affected by being buried in the ground four or 

 five inches deep; and 3rd, if they can produce the disease in an 

 otherwise healthy tree. The answer to these questions will till 

 up gaps in our knowledge concerning the life-history of this 

 parasite and enable us the more effectually to cope with it. 



That the peach leaf rust of Australia is not due to a Uromyces 

 should now be conclusively proved, because of the two-celled 

 teleutospores and the uredospores having a transverse band of 

 germ-pores instead of a single apical germ-pore. 



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