THE SOIL.

Nelson Evening Mail, Volume XLIII, Issue XLIII, 20 September 1909, Page 4

THE SOIL.

MR KIRK'S LATEST ADVICE. WHEN AND HOW, AND THE COST. Almost a surfeit bf matter has been published regarding potato blight, including much about preventive measures. The- latest information, however, by Mr T. W. Kirk, the New Zealand Government Pathologist, who stands as the highest authority on this disease in Australasia, contains, points that potato growers will find worth taking to heart. In an interview in Hobart the other day, he gave the. latest experiences of combating the blight' in New Zealand. Mr Kirk was asked if he had found spraying successful. "Yes, very successful," he said, with emphasis, adding, "but there are some who grow potatoes in New Zealand who will still tell you that spraying is no good, just as, I suppose, there are some fruitgrowers who will say that 6praying for the codlin moth has no effect. Some of those New Zealand potato growers took this stand a couple ef years ago, and trusted to Providence, faring fairly in a, dry season, but this year they got I badly hit with the disease. Spraying is a great success where it is well and lifted sound in a. disease-infected district, and in every, case where the grower has reported the spraying a failure, he has either used bad chemicals in making his Bordeaux mixture, or he has done the spraying, improperly, or both." Questioned as to how many times spraying was necessary, his reply was, "That depends on the season, and the weather. If the weather is wet throe to aix times. In a dry season twice or three times." As to the cost of spraying a crop Mr Kirk said : "From 5s to 5s 9d an acre witE a big machine. Of i course, if a man only uses a knapsack I sprayer over a good-sized paddock it costs more. Often a grower does not start spraying until the disease has got a good hold, and that is another mistake made. Spraying is to be looked upon as a preventive measure, and, accordingly the first spraying must be applied before any disease appears. It is also important to use the proper, sprayin gnozzle, which is the 'Cyclone' nozzle, withi which the under surface of the leaves is reached." * .' At what period of growth is the first spraying done — "When the potato halums are between six and nine inche? | high, and again when in flower. If the disease is bad, and the weather wet, if is necessary to spray oftener, at inter vals of about 10 days. Should rain fall within three or four hours after spraying it will, of course, be necessary to repeat the dressing as soon as possible. i If this treatment is carefully carried out | it will prove effectual in preventing attacks of Irish and early blights, and will reduce most other fungoid diseases, as Bordeaux mixture prevents the germination of fungus spores. It is very important to spray all potato crops which

do 1 not appear to have contracted th« disease in a district ■ whore the disease is found. Such sprayings should be looked upon "as" an insurance policy. It prevents disease. .-' Mr. Kirk produced printed copies of letters '• from numerous New Zealand growers, of which the following from a Wanganui farmer may be taken as an average sampl» :— "With the exception of the 'Hobart Town' variety, I have saved the whole crop, and they seem a truly splendid lot of. tubers. As tho result of experience,:! need hardly say that T.'anv'a- firm -fceliever in' the efficacy of spraying— the more so, as everyone else' .wJio' failed to spray, or who sprayed only once when- the." crop was badly affected with blight, had to face a totalloss of iheir crops." Asked what other remedial measures there were, if any, Mr Kirk said tlwt some varieties of potatoes .resisted the disease morethan others. . TasmaiuanDerwents (Circular Beads), iad often been the first ito. go do%vn in Nevr Zealand. By spraying !the.:disease-graduaUy became P leJivi^lent, Josinff to a certain es. tent its ■epidemic character. After emphasising^the impoftanee of. selecting Hlean s«d, he said that it .was -found, atvantageous to diif seed, potatoes m Bcredaux mixture Wore storing, out rot to do so before planting. _ .--. '■■,