THE POTATO BLIGHT

New Zealand Times, Volume XXVIII, Issue 6042, 29 October 1906, Page 5

THE POTATO BLIGHT

SOME EXPERIENCES AND SUGGESTIONS. (To tie Editor, “N.Z. Times.”) Sir,—As the season for cultivating potatoes has again arrived, accompanied by the same disease that played such havoo last season, permit mo, per medium of your valuable- columns, to draw tho attention of potato farmers ‘to the following peculiarities appertaining to- the disorder. For instance, last season, tv'o acres in one field were planted witlT potatoes, all the seed being of one kind. The growth was, not sprayed with Bordeaux • mixture, o-r any other specific for so-called late Irish blight. When the crop had grown for about half tho time irequircd for full development, there appeared, from tho strong and rapid growth, to bo promise of a good return, but a change took place; the crop (with tho exception of a small strip of about twenty feet -wide running down the whole length of tho centre of tho field) commenced to wither; presumably the disease had been present from the first appearance of tho plants above ground, but had required this length of time to give effect to ito presence. .Result, the crops on each side of the narrow strip were destroyed, but the strip mentioned, notwithstanding the presence and close proximity of disease on each side, grew well, giving a good return. All the potatoes were sound when dug up, and are being used for deed this season. ■

Another instance. A farmer planted eight acres in potatoes, using a variety of seeds, some being called blight-remsting (advertised as Such). The whole crop was carefully sprayed .several times -with Bordeaux mixture by himself, as the crop was intended for sale purposes. Restilt, at end of season, or digging up'time, the whole of the crop was ruined and' lost—the loss being attributed to the presence of the so-called potato blight. Yet another. A farmer plants one aero in potatoes, and fellows up the Bordeaux mixture treatment carefully. Result, some patches of this potato plot matured properly, but the balance was completely destroyed by said blight. In the New Plymouth district a potato grower publishes that, during five years, he has treated his seed by soaking them in the dame kind of mixture that his father previously used, as a specific against late Irish blight; no further treatment in the way of spraying, etc.; result, return of a good crop each year. This treatment, if correct would, I should think, show that the disease was present in the potato seed only, and is not a blight that is contagious or carried about by the wind.

Our scientists "tell us to spray the under portion cf the plant leaf, for it is there the blight takes) shelter. Personally, I know it is there the aphides take shelter in countless num-. hers, and these insects. live by sucking up the ■ sap from the plant, though nature intended this sap for tho development of the tubers), and the deprivation of this nutriment causes premature decay. In some- instances where the Bordeaux mixture has been used and ended in failure, the explanation given was that the mixture had not been properly applied; in other cases where Bordeaux mixture had been used and failed, it was said the ingredients were of an inferior kind. I have not yet (Ten it stated in print that the different; classes of soil and locality were responsible for success or failure in the growth of potatoes, though I have been told by practical farmers that potatoes during’ the prevalence of the present disorder thrive well in light dry boil, and that aphides or insects do not thrive on this claaa of soil. On the other hand, it is surprising how quickly these insects multiply on potato plants where the soil is heavy, and more especially so where tho locality is damp. ■ ’ ' In conclusion, allow me to state that the potato blight can not bo found present, without also .finding aphides present. and, to say the least, these insects. which exist in countless millions, in different stages of growth, ought to ho dealt with in. some way, if only because they kept company with tho potato plague or blight. The potato disease, though yet early in the season, is now very bad in all the props I have seen in Otaki, and from general appearances promises to bo worse than during last season, and will probably destroy most of the crops. Tho present time gives a good opportunity for deciding onoe for all if the Bordeaux mixture, when properly applied, is really a specific for potato disease or blight. Let some person experienced in the use of the mixture come along, spray a few rows in each of the affected crops, and not touch others in the same plots, pegging off those treated, and later on repeat the treatment and await result. As tho expense would be small, there is ho doubt our local potato growers would not object to a small contribution each, after which, or in future seasons (if said treatment is successful), tho potato producer would not require to continue experimenting at 3iis own cost* wliilst the blight is destroying tho crops.—l am. etc., A. J. KNOCKS. Otaki, Otrtober 24.