THE RAGWORT PEST

Hokitika Guardian, 31 March 1930, Page 2

THE RAGWORT PEST

SODIUM CHLORATE RECOMMENDED. The spread of ragwort in certain districts of Otago lately has been proceeding with a rapidity that has not unreasonably given rise to a good deal oi comment particularly inasmuch as the weed appears to be securing a dangerously strong bold on first qualify griming land in some parts of the province. But the position in the Otago provincial district is nothing compared with that in Southland, where the goldenflowered pest now covers acre after acie completely. In fact in some places it is impossible to discern any othei growth whatever, and paddocks look as if they had been expressely devoted to the cultivation of the weed. The members of the Dunedin Chamber of Commerce who visited Southland this week, on a short run of a few miles, encountered ample evidence to support the above statements in regard to the manner in which ragwort is flourishing and even their lay minds were struck with the seriousness of a problem which seems to be growing more grave eveiy season. On the road from Invercargill to Riverton some astonishing crops of this noxious weed were seen, more than one of them covering paddocks of many acres in extent. Good land in the vicinity of the Oreti and New Rivers was particularly badly affected, and the weed had so complete a hold that one was tempted to assume that land holders had given up the uneven struggle, and were prepared to allow their property to be overrun. It appears, also, that-this particular part of the province is by no means unique in respect to the growth of ragwort. The writer has soon the weed in great abundance in other parts of the western district of Southland and was told this week that there are other localities equally as dirty. Many parts of Otago suffer in a similar fashion, although it is doubtful whether, so much good land could be found to be affected in the northern province. .In. the Tap an u i-Crou'kston-Heriot-Ivelso district there is a let of cleaning, up to be done, and much very fine, grazing land has suffered as a result of the spread of the weed, but for the, most part the ragwort in Otago is to be found on second-class land apd rough corners which defy cultivation. And, moreover, not an inconsiderable portion of the pest in this province is to be found in places from which the State should have cleared it away.

The problem of the control and the ultimate eradication of ragwort is one that has occupied the attention of research workers at the Cawthron Institute for some years, and a good many expedients have been tried with little success. The latest assault to be made oil the pest in the south has been Carrie dout through the medium of the

cm no bar moth, hundreds of which were liberated in various parts of Otago and Southland. It was thought at first that these insects would be unable to stand the rigours of southern winters, but such fears have been proved to be without foundation, and the moths have increased their numbers very noticeably in some localities. Rut their depredations in respect to the weed have been less effective than’ anticipated, and although there is no reason to suspect that in time they would not make a very considerable impression on the growth of the pest, it cannot be gainsaid that the remedy is rather too slow. Since the moths were first liberated the position in regard to ragwort has grown steadily worse and it would seem to be imperative now that some speedier method of eradication should be found. As a result of experiments carried out by the fields division of the Department 'of Agriculture, there appears to be good reason for hoping that future attacks on ragwort will prove more effectual than have those carried out in the past. Sodium chlorate, which has already proved itself in respect to Californian thistle, and to an even more remarkable extent in regard to St. John’s wort, has been found to have a particularly deadly effect on ragwort, and it is likely that farmers who are really concerned about the serious increase in this weed will be trying out this new controlling agent during- the next few months. It must be apparent to landholders, particularly dairymen, that the use of sheep, though effective enough in many cases, is not a satisfactory solution of the problem, and it is suggested here that they will not be acting unwisely if they get into touch with the Department of Agriculture with a view to securing supplies of - sodium chlorate for the purpose of carrying out experiments for themselves. Sodium chlorate, which has no injurious effect on pastures, and can be relied upon not to affect live stock, even if it is applied on land while it is being grazed, can be used either in dry of liquid form. Used as a spray it is likely to prove more effective than if applied dry, but where there are large expanses of land to be treated it would be difficult and expensive to spray the whole of. it,, so that the farmer must of necessitly fall back upon its use as a top-dresser. However, both methods can he relied upon to make an impression on the worst stand of ragwort. When the substance is sprayed on to the weed it has a better chance to act quicidy, hut whether it be in liquid or dust livm it eventually reaches the roots of t 1 e plants and kills it right out. St. John’s wort; which has proved a not inconsiderable nuisance m many parts of Otago, is comparatively easily disposed of by means of the use of sodium chlorate, and Mllhongh the Californian thistle has proved to bo a

much harder plant to kill it is hoped that the next few months will show that stubborn growth has to give the chemical best.