6.^.8 



Journal of Agriculture, Victoria. [ii Sept., 191 i. 



XIII. — CoLAc Plot— Peroentagb of Irish Bi.ioht. 



Black Piiiic 1' 



Bedford 



Norfolk 



Sussex 



Wellington 



Marlborough 



St. Albans 



Sutton's Abundani-i' 



Adirondak 



Brown's River . . 



Orr's Wonder 



Green Mountain 



Up-to-Date 



New Zealand PlnUcyi 



per cent. 

 38-4 

 36-5 

 38-4 

 4-5 

 100 

 100 

 100 

 20 

 5-8 

 100 

 100 

 Nil 

 55 

 55-3 



57-9 



Average. 



per cent. 

 44-2 

 42-7 

 44-2 

 6-4 

 100 

 100 

 100 

 17-2 

 9-1 

 100 

 100 



48-6 

 44-4 



58-1 



XIV. — Leoxgatha Plot. — Percentage of Irish Blight. 



Bruce . . 



Black Prince 



Adirondak 



Scruffle 



Green Mountain 



Champion 



Brownell's Beauty 



Vanguard 



Scotch Gny 



State of Maine . . 



Average. 



per cent. 



70 

 100 



72-2 



54-8 

 100 



69-6 

 100 

 100 

 100 



36-6 



80-3 



Conclusions. — Opinions differ as to the period in the life of the plant 

 when it is liable to attack; also as to the attack of the tubers, and the 

 actual resistance to attack of certain varieties. 



From careful observation on the.se points in the field, it was found to 

 attack the plants from 2 in. high up to the last stages of growth. It 

 was evident that when the spores are being carried through the crop it 

 matters little, if weather conditions are fa\ourable, whether the plants are 

 just over ground, or in the last stages of growth, except that in the latter 

 case the injury to the plant is not .so great. 



In the case of the disease in the tubers, it is controlled entirely by the 

 weather conditions that prevail after the disease has struck the crop. If 

 rain falls shortly after the crop goes down, the tubers are sure to show 

 a high percentage of disease, unless they have reached a stage when the 

 skins are set. 



The resistance of cei'tain varieties does not appear to be as satis- 

 factory as could be wished. An instance is given of a variety in one dis- 

 trict showing a total loss, whilst in another district among a badly 

 diseased crop composed of nine or ten varieties, it escaped altogether. 

 A"-ain, Up-to-Date. a recognized resi.stant variety, failed in one plot from 



