:o Sept.. 1909.] 



The Victorian Potato hidiistrv. 



599 





The first is the accuracy of the ori- 

 ginal description of the disease as it 

 affects the leaf and tuber, as well 

 as the microscopic appearance of 

 the fungus. This should be com- 

 pared with similar figures in the 

 Bulletin just issued by this De- 

 partment. The second point 

 worthy of note is the difference in 

 the leaf of the potato 65 years ago 

 as compared with the typical leaf 

 taken from Bulletin No. 7 recently 

 issued by the New Zealand De- 

 partment of Agriculture. With- 

 out insisting too much on the ex- 

 tent of the changes which have 

 been brought about by half a cen- 

 tury of selection and breeding, 

 there is no doubt that the foliage 

 has been developed in the direction 

 of size and denseness step by step 

 along with the corresponding in- 

 creases in the total yield per acre. 



The Steps to be Taken. 

 To meet the present emergency 

 in the potato business the hearty co- 

 operation of every potato grower in 

 Victoria, whether his plot is a few 

 yards square or his farm contains 100 acres of potato land, must be 

 secured. No effort must be spared to stamp out the disease. A reduction in 

 the yield for a single year must be cheerfully borne in view of the enormous 

 interests at stake. On an average there are 50,000 acres under potatoes in 

 Victoria each year. Should the disease become established, spraying with 

 Bordeaux mixture is the only method to adopt to check it, but this method 

 will not eradicate the disease. The plants have to be sprayed when they 

 are a few inches high, and the spraying requires to be repeated two or 

 three times or perhaps more frequently during the growing season. The 

 total cost works out at a minimum of j[^2 per acre, the maximum may be 

 over ^3. The additional cost of growing the Victorian crop will therefore 

 be at the very least ;^i 00,000 per annum, but this expenditure of ^100,000 

 does not in any way lead to an increased return similar to what might be 

 expected if the same money were spent in fertilizers for the crop. So far 

 as the blight is concerned it is all dead loss. Should the Victorian industry 

 be handicapped by a yearly charge of £^2 per acre there is no doubt that 

 very many districts will have to abandon potato growing. 



Such being the alternative, the following measures must be adopted : — ■ 



I St. Only clean seed should be used, and this must come from 



districts which are known to be free from disease. In addition 



to this all seed must be cut and soaked in formalin or other 



antiseptic. 



2nd. All potatoes, ivithout any exception ivhatcvcr, for the next two 



seasons should be grown on new ground. 

 3rd. In future years a more systematic rotation of crops should be 

 carried out than what has been the case up to the present. 



EARLY STAGE OF DISEASE, SHOWING 

 CHARACTERISTIC BLACK BLOTCHES 



ON LEAF (from Bull. No. 7, 1907, 

 N.Z. Dept. of Agric). 



