298 



Journal of AgriczUtural Research 



Vol. XVI, No. II 



TablB II. — Effect of various seed treatment on germination of Irish potatoes 

 PLANTED MAY l8; COUNTED JUNE 15 



PLANTED JUNE 19; COUNTED JULY 1 5 



Charcoal 



F. oxysporum. 

 Onion luice . . . 

 Control, cut. .. 

 Whole seed. .. 



82 

 o 



55 

 88 



99 



Dusted. 



Sprayed. 



Dipped. Expressed juice of onions. 



Dipped in water. Average field performance. 



No treatment. 



a SurrH, J. L. et al. antiseptic action op hypochlorous acid and its application to wound treat- 

 ment. y» Brit. Med. Jonr., 1915, no. 2847, p. 129-136. July 24i 1915) 



In the first planting the charcoal treatment gave better germination 

 than the controls, but fell behind in the second planting. None of the 

 others were worth the trouble of treatment. The whole seed gave much 

 better stands and of more healthy vigorous plants. 



Third, in applying the best-known cultitral practice to the propagation 

 of the potato. For this no rules can be given. Each farmer should 

 judge the condition of his land, its moisture content, tilth, and apparent 

 needs. Rotation with grain and legumes is advisable, allowing the land 

 to be cropped with alfalfa as many years as possible before potatoes are 

 planted. Methods of irrigating and cultivation during the growing 

 season should be investigated at the time for the field in question. 

 Plate 41, A, shows a field planted with good seed, but owing to the dry- 

 ness of the soil at planting time infection set in, and the fungus destroyed 

 from 60 to 80 per cent of the seed, with the resulting poor stand. 



GENERAL DISCUSSION 



Infection of potatoes by F. oxysporum from the soil through the seed 

 piece has never been recorded before, so far as is known. That it is of 

 widespread general importance on alkali soils is believed, from conditions 

 noted in several potato-growing regions of the West. In parts of the 



