THE POTATO BLIGHT.

Taranaki Daily News, Volume XLVII, Issue 81847, 14 September 1906, Page 3

THE POTATO BLIGHT.

ITS CAUSE, A THEORY DEMONSTRATED. There are few people who have given the potato blight more careful study than Mr David Teed, the we'l known New Plymouth matfufactur ing chemist. He has carefully observed the working and effect of the blight and conducted experiments of a varied nature, with the idea of discovering the cause of the disease Knowing this, a Dailv News representative called on Mr Teed for some particulars of his investigations and conclusions., Reeling they would be of value to the general public, and these he courteously supplied, going to some pains to show in his laboratory the microscopic and other work connected with his research.

Asked what led up to his experiments, Mr Teed said that about 12 months a-'0 his attention was drawn to some misses in the rows of a pc tato patch, and an examination of the tuber found very small white insects, which he mounted for microscopic examination. Many persons interested at the time saw the en larged insects, which were very much alive and running about for two days, but arc still distinctly visible undei the cover glass. Many who saw them called them "rabbits." The diseased tuber he put into a tightly covered tin, and after three months thousands of these insects had developed, and, further on, a tiny fly was seen, but disappeared, together with nearly all the "rabbits.'-' The latter are again increasing, living on the rotten potato.

The blight had made its appearance over most of the' colony, and many theories were advanced as to its cause; e.g., an Auckland paper reported its appearance at the Great Barrier, stating that no potatoes had been imported there, and that consequently the blight must have been carried by the atmosphere, overlooking the fact that the germ might have been in a fruit case, flour bag, or the garments of a visitor, etc. Further, the atmosphere, being loaded with such germs, animal life would hardly escape its baneful influence.

The Government Agricultural Department advised spraying with the Bordeaux mixture, and at the appearance of blight in his own crop Mr Teed used the mixture and no< ticed at once the beneficial effect. Again and again the blight appeared, at intervals of about a fortnight; again and again the spray' was used and the blight beaten,' His neighbour adjoining, Mr Teed continued, had the same results with the same material. Another, close by, sprayed once only, but lost his whole crop, which the previous year had produced sufficient for his house requirements, after disposing of several sacks. All around who ignored the spray lost all. Mr Teed's own small patch produced sufficient for his house requirements for the year, with more seed potatoes than required for early and late crops for the present season.

THE CAUSE OF THE BLIGHT. Referring to the cause of the blight, Mr Teed said: ''ln my early observation, I thought the 'rabbit' was the destroyer, being found, as before stated, in the act of consuming the tuber, which, ceasing to nourish the foliage, the stem decayed at the surface of the ground. On spraying the leaves, 1 now and again di'turb(d an almost imperceptible moth (or fly), and the idea arose that these might have something to do with the spotted leaves, by the injection of a poisonous ferment. 1 thought of the African tsetse fly on the destruction of horses, the sting of the bee, katipo, snake bites. Although a most minute portion of tlie poison is injecteil into the bloocl it carries dire effects by ferment or'otherwise, and is sufficient to cause death,

">jow, ;is (he blood is the life of animals, so the sap is the life of plants. In the Old Country, the farmers' anxious endeavour is to get the swede turnip crop so forward that the rough leaf should be well advanced before midsummer day. for fear the dreaded fly should attack and destroy the winter crop. "SlmuM not this b'- an indication

that the potato fly mentioned above injects by its sting a poisonous Rub stance (ferment.) into the sap, caus ing the spotted leaf, which, if left un checked, destroys first the leaf anc afterwards the tubers below?" qucr

ieel Mi Teed. PREVENTATIVE MEASURES. '•What do you recommend by way of prevention, Mr Teed'r" asked the News man. "Well," replied Mr Teed, "I re -

commcd the following First, seed should not be saved from diseased fields, and should be < ;-.v fill v selected. Second, a change of'sce'd is de-

sirab'e and a change of land. Third, neither disease-resisting varieties nor cultivation can be trusted to ward off the disease, but repeated spraying with copper mixture, e.g., Bordeaux mixture has been found most effective in Ireland. Vifth, strong' nitrogenous manure, especially nitrates of pota-li 01 mml.i ;md ammonia, should not be used, and th" potato 'sets' should not be cut."