WAIMATE

Timaru Herald, Volume CXXXVII, Issue 19451, 28 March 1933, Page 12

WAIMATE

THE WEATHER. The rain which commenced early on Saturday morning in Waimate registered a total of 55 points up till 9 a.m. yesterday, and as a consequence farm lands generally throughout the district already bear a much freshened appearance. Rain threatened again shortly before mid-day yesterday, at which time a strong southerly set in. but apart from a shower of very short duration, no further rain was recorded. CLUB ROOT ON FARM LANDS.

At a recent meeting of the Waimate Farmers' Union, Mr A. W. Barnett (ex-president), in response to a request from members, gave the result of his investigations in regard to the clubroot disease on farm lands, and the means to adopt for its eradication. Mr Barnett stated that he had been in communication with the Director of Fields Division, Department of Agriculture. from whom the following communication had been received:— “With reference to your communication requesting to be supplied with certain information relative to the spread of club-root and the best way to prevent its spread, research work in this connection has been under the control of Dr. G. H. Cunningham at the Plant Research Station, and consequently I have consulted Dr. Cunningham prior to replying to your letter. Dr. Cunningham advises as follows relative to the queries contained in your communication: “(1) We have not secured any evidence indicating that the disease is carried with the seed, nor is any such recorded in the literature. Field evidence would tend to indicate that it is spread in this manner, but as said, we have been unable to confirm this experimentally. “(2) Mr Gibb’s work indicates that 33cwt. of burnt lime, or 3 tons of carbonate of lime, will hold club-root in check, provided (a) the soil acidity is not unduly high, and (b) the initial spore load is unreasonably low. As success in combating club-root depends on these factors, it is perhaps advisable to enlarge upon this. It is not possible to combat club-root by liming land which has carried a heavy infection of club-root the previous season; for there is a direct correlation between the number of spores in the soil (spore load) and the degree of success which may be secured. The object of liming is to reduce soil acidity, for club-root cannot thrive in alkaline or neutral soils. Consequently when the acidity of the soil is unduly high, lime applications would have to be heavy. *The time of application is also a factor, since lime acts relatively slowly, the carbonate being much slower than burnt lime, owing to its greater insolubility. To summarise: Liming is effective only when application is made some time in advance of sowing the crop (about three months in the case of burnt lime), and then only when acidity is not unduly high, and a heavily infected crop has not been grown on the land the previous season. “(3.) Where small patches occur in the field, spread may be checked by applications in the manner outlined, and when lime is added to the manure sown with the seed. No means of preventing spread in the growing crop is known. Infection is spread to land to be used for cropping by using such areas as run-offs for stock feeding on infected crops, or carting out roots on such areas. Hence areas should be limed, whether lea land or otherwise, as this prevents the disease from becoming established from odd spores carried by means of animals, cultural implements or the like.” Mr Barnett went on to say that Lincoln College was reported to have said in regard to numerous inquiries that club-root appears to be more common in Canterbury this year than in former years, and some growers, not having had any previous experience ! with it, are unaware of the methods 1 which may be adopted to prevent the : disease spreading over the whole farm, i The following notes on the symptoms ; and control methods were supplied:— ■ Infected plants, which generally : occur in well-defined areas, are stunted ■ and somewhat discoloured, and in dry j weather become badly wilted. The most characteristic symptom is the j presence of irregular swellings varying , in size from that of a pea to that of a cricket ball on the roots and lower ( parts of the bulb. In advanced stages < these swellings frequently rot. There is | no cure for the disease once it has . started, but prevention is possible when , a farmer realises that he is dealing with a serious infectious disease.

Infection of the crop takes place from the soil. The disease may be confined to a large or small area or the whole field may be infected; but it does not spread of its own accord, beyond the area of contaminated soil. The soil becomes contaminated mainly by sheep feeding on diseased roots, and then moving on to healthy ground —either in the same field or another. The disease may also lie spread by carting diseased roots on to healthy ground or by moving stock and implements over contaminated ground. The organism causing the disease will live for several years on the soil, so that stock should not be removed from a diseased crop on to a field in which it is intended to grow turnips or rape during the next five or six years, and a similar period must lapse before growing a susceptible crop again in the same field after a diseased crop. The practice of growing one susceptible crop after another, e.g.. turnips after turnips, or turnips after rape, and so cn, is one of the most common causes of heavy infection if the disease is present in the first crop. The destruction of wild turnip, shepherd’s purse, and other cruciferous weeds forms an essential part of the treatment. By adopting these precautions the disease, if present, may be prevented from spreading and may in time be exterminated. Wet and sour soils favour the development of the organism, so that draining and liming may assist in control. Lime at the rate of one to four tons of burnt lime per acre according I to the acidity of the soil, applied at least three months, but preferably twelve months or more, before sowings will considerably reduce infection. The “Bruce” turnip recently introduced into New Zealand from Scotland has proved to be highly resistant to club-root, but the seed is not yet availab’e in commercial quantities. Mr Barnett was accorded a hearty vote of thanks for obtaining such useful information for members.