CLUB ROOT IN SWEDES.

Cromwell Argus, Volume LXI, Issue 3162, 11 May 1931, Page 3

CLUB ROOT IN SWEDES.

CHECKING THE DISEASE. RESEARCH WORK RESULTS. Investigations are being carried out by the Plant Research Association, in co-operation with Massey Agricultural College, Palmerston North, into means of checking clubroot in swedes. The woi-k is in the hands of Mr G. Gibbs and the results have been very encouraging, and farmers in the Manawatu and other districts with similar climatic conditions can now be definately advised of the steps to be taken to reduce the losses caused by the ravages of the disease. The investigations show, says the Manawatu "Daily Times," that club root can be kept in check by the sowing of a variety of swede that is resistant to the disease, and by the application of burnt lime to the ground at least three months before the crop is sown. Basis of the •Experiment. Crops grown on the Massey College area under this treatment and those in the control plots indicate clearly what .is being accomplished. Mr Gibbs states that the area was affected last season with a fairly severe attack of club root, and in the ordinary course of events would not have been sown in swedes this season. The experiment was based on the results of peliminary trials conducted on the Plant Research Station farm, and consisted of the application of burnt lime at the rate of 1 2-3 tons per acre and carbonate of lime at the rate of 3 tons per acre, broadcast over the ground and harrowed in three months "before drilling the seed. The seed was sown by a double ridger with Herning's swede in one box and. Crimson King swede in the other. One-half of each block was dressed with superphosphate and carbonate of lime in equal quantities, at the rate of 6 cwt per acre, and the other half with basic slag at the rate of 3 cwt per acre. The Results.

Although only a few roots have yet been pulled and examined, the Herning's swede in the burnt lime plots is apparently practically free from the disease and growing vigorously, especially in the plot that was treated at the rate of three tons per acre of burnt lime. In the carbonate of lime area the growth is not so good, but very little club root can be found. A number of the roots are diseased in the unlimited control area. The Crimson King swede in the three tons of burnt lime area is only materially affected with the disease where the fertiliser has been super and lime, but where slag was used as a fertiliser . the plants are very healthy and compare favourably with the resistant Herning's. In the 1 2-3 tons of burnt lime area the super has very seriously increased the amount of club root, and a lai'ge number of the plants are dying out, while those fertilised with slag are of much better development. In the carbonate of lime plots on control plots practically no difference can discerned by the eye between those plants manured with super and those manured with slag. Both appear to be suffering from severe club root. It is pointed out that the idea of applying the lime three months before sowing the seed that sufficient time would elapse to enable the soil solution to be changed from acid to alkaline, in which the club root oi'ganisms would not develop. It is thought that the very dry period during late November and December reduced by a month the time that the lime was actually working in the soil, and that had this period been more, moist a better control would have resulted. This amply supported by the reports of an experiment on similar lines carried out at Gore, where from a superficial observation both the burnt lime plots appear to be practically free from disease, while the unlimed plot is badly clubbed, especially where the super and lime was sown with the seed. In this experiment the whole crop was sown with slag except a small portion of the unlimed control, which was sown with super and carbonate of lime on a 50-50 basis at 6 cwt per acre.