6oo Joiir)ial of Agriculture. [lo Sept., 1909. 



Regarding this Year's Seed. 



Nearly the whole of the danger of the introduction of the disease is 

 bound up in the question of clean seed. Any seed which comes from an 

 infected district is liable to be contaminated even if it is not itself diseased. 

 The spores of the fungus when once an outbreak occurs on the foliage of 

 plants are carried from plant to plant by the slightest breath of wind, and 

 should the conditions be sufficiently moist thev germinate at once, and 

 hence from a single centre of infection the disease spreads with great 

 rapidity. This is the explanation of the character of the disease which 

 has impressed itself most deeply upon the popular memory in localities 

 where it has occurred in virulent form. The common expressions — " the 

 whole paddock was blasted in a single night;" "the crop was all right 

 in the evening, but was all blackened next morning" — are absolute facts 

 which are explained by the known characters of the fungus and the rate 

 at which the spores can be disseminated over an area of several acres. 

 Wind carriage of spores will not, however, spread disease across long 

 distances from one localit>- to another, hence as the result of the Inter- 

 State Conference it has been decided to recognise a half-mile limit as con- 

 stituting the zone of practical safety. On the other hand clean seed mav 

 be contaminated by contact with diseased tubers or by being placed in the 

 same bags as were formerly used for diseased potatoes. It will therefore 

 be seen that the above recommendations with regard tO' seed potatoes, if 

 faithfully carried out, are practically certain to stamp out the disease. Cut- 

 ting the .seed is another safeguard by revealing any small patches of red 

 rust beneath the skin of the potato, which might otherwise escape obser\a- 

 tion, and while the seed potatoes are being handled watch should be kept 

 for anv softened patches. Anv soft patch should be at once cut into, and 

 if at all suspicious the potato should be thrown into a special barrel to be 

 dealt with as indicated below. In adilition to these precautions the 

 potatoes should be soaked in a solution of formalin — i lb. to 30 gallons 

 of water — for a period of two hours. Before immersing in the solution, all 

 dirt should be removed from the surface of the potato, as it is obvious 

 that a thick coating of stiff soil will prove an effective protection from the 

 action of the antiseptic to any patch of disease which mav lie immediately 

 beneath it. In addition to these precautions every grower who has alreadv 

 planted or has in his possession seed potatoes from Tasmania or South 

 Gippsland is earnestly requested to communicate at once with the De- 

 partment. If this crop is alreadv planted it will be watched and should 

 disease appear steps will be taken to eradicate it. As the Government has 

 determined that a fair share of the co.st of eradicating the disease will be 

 defrayed by this Department farmers should not be held back from placing 

 this information at the disposal of the Department in consequence of any 

 fear of financial loss. If no disease develops no harm will be done, while 

 on the other hand if the disease does develop they are certain practically 

 to lose the whole of their crop even if they inform no one whatever of the 

 fact of its existence. By means of the assistance that can be rendered bv 

 the staff of the Department it Is highlv probable that a farmer can be 

 safelv piloted through a dangerous period with a minimum of expense. 



Rejected- seed placed in the barrel should he boiled before feeding to 

 pigs. 



New Ground for this Year's Crop. 



However carefully the old crop of potatoes has been dug. it is certain 

 that manv small marbles are left behind and thus constitute the danger nf 

 carrying on disease from year to year. Under favorable circumstances, 

 every eye or even portion of an eye of .^ potato will sprout. If this has 



