THE POTATO PISEASF.

Otago Witness, Issue 2660, 8 March 1905, Page 29

THE POTATO PISEASF.

-For the first time in the history of tlie colony the potato crops are threatened w<th a serious attack of tliat disease which, on account of the- terrible devastation and famine it wrought in Ireland in 1845 and 1846, has ever since been known as ' ' the Irish blight." Mr J. Shiel, of Messrs Nimrao and Blair, who has had experience of the \lisea. c <±

in Ireland, has recently been making^ some first-hand observations concerning its ravages in this colony, and his remarks thereon, as communicated to us, s.re of considerable interest at this juncture.

"The diseas-e," said Mr Shiel, "was, I think, first noticed in the Auckland district;. and this was* followed by" an outbreak in tie Hutb district, afterwards spreading to the West Coast of the North Island. It has also made its appearance in South Canterbury and dn the West Coast of the Louth Island, but so far there has been no lvport of its outbreak in the Oamaru' distiict. Thh is, I judge, on account, of the warm, dry, limestone soil in which the potatoes are there grown. ; "My knowledge of the potato blight in, Ireland, gathered some 25 or 30 years ago, is that it is caused by the absence of a complete change in seed, accompanied by a continuity of bad wefe seasons. At that- tint'tho blig-fit got possession of the potatoes, and in some districts in Ireland tht crop was completely ruined. In some inscanees, in order to try and save part of the crop, the tops, of the potatoes — the horns — wero cut to prevent the disease from travelling down the stem into the tuber. In com* instances spraying was at*e>pte<:l, but nofc wiih a very beneficial effect. "'The disease first mak-os it«H>lf manifest on the under side of the leaf of the plant, in the chape of a wjiite floury substancp. The leaf fhen begins to wither, and as it withers the disease travels down into tlve tuber, with the result that the potatoes ultimately rot. / '• I have lately been inspecting six 'different crops of potatoes grown in river-bed soil in the Balclutha district. It is gcod free soil subject to a good deal of moisture Ont early variety showed signs of the dib^a-io more than the later varieties. A c l% cp of Northern Star — a recently-imported variety — was strong- and vigorous, and as *_r ascould be seen it was refcis-tinej the disease. From appearances it should dig up 30 iov." per acre. Another late variety, a'*o of recent importation, showed slight si,;n3 of the disease on tho back part of the leaf If this crop gels much more wet weather tha blight will travel down the stem, and ultimately reach the tuber, which will thon rol and become useless.

" The potatoes in the Clutha district are being sprayed with a mixture of su'p^ite of copper, limo, castor oil, and water in proportion?. We are also experimenting with Montauk, and will be able to report on the results shortly.

'" In my opinion, the appearance of thedisease is owing to the wet winter, fo'lowed by a net spring and wet summer. If lfexu year wo have a fairly dry season I do not think we shall bo troubled with a reappearance of the disease, except, perhaps, in low-lying si\amp land. "A large number of the crops pro affected by thp blight this summer. Ami I und-ev-

stand that the Government is taking ste-ps to check the spread of the disease by prohibiting the- sending of potatoes out of any area declared affected. This is a wise step, and the farmers everywhere should second the Government efforts by vigorous spraying, and in all other ways possible endeavour to rid the colony of the* disease."

Mr Shiel's remarks ?eem to point to one or two striking possibilities. The decreased acreage this season, to which we have already referred, together with the spread of the disease and the Government prohibition, must affect the i.rice of potatoes. And should it turn out that the Oamaru district is the only one entirely free from the blight, then it stands to reason that Oamaru potatoes will he much sought after. A few shrewd speculators, anticipating 1 such an eventuality, have already purchased largely for forward delivery at up to £4 per ton, and there is therefore the possibility that Oamaru Dcrwonts may see high prices before the season is through.

Mr Kirk, the Government biologist, has (says the North Olago Times.) paid a visit to the Oamaru district and discovered the Irish potato disease in several crops, but tho extent is not great. Nevertheless he urges the advantage of spraying, even where the crops have not been attacked.

The potato blight, although not yet general throughout the "Waimate district, has obtained a good hold (says the Christchurch Press), and already it is estimated by a Government official that over £1000 worth- of damage has been done. At Glenavy, _pn the- extreme end of tho "Waikakahi, there is only one small patch affected. There is none of the disease through the Gorge at AVaihao Downs and Kapua, but it is bad at the Hook, slight at Hannaton settlement, and almost every batch near the town is affected. One beautiful crop of three acres, estimated to be yielding 15 tons' per acre, is completely destroyed, and looks as though a fir© had swept it. Mr Garland, with a crop worth £300, will also iose heavily on it Those who grow small patches, sufficient to last them part of the year, will, in the most affected cases, lose half. Growers generally eau hardly believe that the loss will be so great, and even though strongly urged by the Stock Department to spi*ay immediately, they do not seem inclined to take the precautions the situation demands. The principal reason is that most farmers are in the middle of wheat and oats harvesting, and the uncertain weather makes them eager to finish getting it done. If spraying is at once carried out many crops will be saved yet, but the present loss alone will seriously affect the price of potatoes for a time. Crops are very good, and there may be sufficient to meet all demands, but until this is definitely known prices will keep rising.