DRY ROT IN SWEDES.

Shannon News, 27 February 1925, Page 3

DRY ROT IN SWEDES.

EXPERIMENTS AT GENTHAL DJiVEIL- , GPMENT FAR|M. Experiments or more than usual interest to farmers are being carried put at the Central Development F.arm this year under the direction of the Direc- '■* 01 uie mqiog-ical Laboratory (Mr R. Waters) in an endeavour to determine which of the varieties of swede upon the market is least subject to dry rot. The position in JSew Zealand in regard to this disease is a veiy serious one. The rot, which is the result of the activity o.f a fungus lias been- com, puted to take a yearly toll of 25 per cent of the swede's grown in the country, thereby .reducing the carrying capacity of the farm lands, of New Zealand by 5 per cent, owing to the inability of farmers to carry over the winter the stock required for frie spring and autumn flush of feed. Whilst the disease is common to all parts of New Zealand, Southland, which with its rigorous climate is particularly dependent on this crop for winter feed, and where incidentally swedes grew remarkably well, has been most affected. In many inthat district have been destroyed, and stances 100 per cent of the crops in the growing of swedes has become so risky as to practically rule this crop out as a winter feed. Although the disease is known in other parts of tihe world, notably in the south -of Sootland, Northern Germany and Denmark, New Zealand possesses the unenviable distinction of suffering more from the ravages of dry rot than any other part of the world, the attacks in other countries being, indeed almost negligible. In this country, < however, the position has become so serious that the Government Biologi-l cad Department Jhas (instituted re- I search as to a means of combatting the, disease, and it is in connection with | these that the experiments at the Gen- , tral Development Farm are being carried out.

Twenty-five different varieties are being grown at the Farm, tttiese being planted in long rows, side by side. The seeds have ibeen obtained from •>-> "n different firms throughout New Zealand, most of the varieties toeing duplicated through getting the same brand from different localities so that in all there ar e 48 lots sown. These include also, one variety from each of Holland, England and Sweden, which have been specially imported by the Government and which are claimed in the countries where they are grown, to be immune to the dry rot fumgus.

Wuilst the experiments at tihe Farm will necessarily not be conclusive, the result, as indicating the best seed to sow in the meantime, until a means of checking the disease with some certainty has been discovered, will be of considerable value and will be appreciated by those farmers who. iiave experienced tihe ravages of ilic disease.

The dry rot, the appearance of which is well-known to farmers, first makes its appearance as a series of whitish spots with a dark Iborder on the leaf, these being'surrounded 'by concentric rings of minute Mack speck? hardly noticeable to the naked eye, and which are the actual fungus attacking the leaf. Little of the life history of the fungus is known and how long elapses from the time it first makes its appearance on the leaf until it attacks the root has not been ascertained, but later a dry rot of tihe root at the bottom of the leaf may be noticed. The wider rot which causes the breakdown of the root, is not,,'however, the dry rot, but is ca ised bv the bacteiiia. of decomposition attacking the dead tissue. ' ' The main result of the disenpp nt present, is that, instead of the swede Toeing a certain and reliable crop for

the months of August and September when feed is at its lowest, the early appearance of the rot causes farmers to feed them off in May and June, making it necessary to provide further feed for the later m<mths. The result of the Department's researches will be awainted with the keenest interest by every 'branch of the fanning community.