THE WAIRARAPA TURNIP TROUBLE

New Zealand Times, Volume XXIX, Issue 6176, 6 April 1907, Page 3

THE WAIRARAPA TURNIP TROUBLE

I DKXTIFIEi) HY MR KIRK. The disease in some AVairarapa turnip mops uhieh has puzzled growers Ins been ideatdied-by the Unvernmcnt BhdagKt a-i phorna napo-brussicoe ros. fir-,1 Vb'vrihc'l by Bostrup in 181J3 as r!(-1 tiuiivo to turnip root’; in Denmark. A bnllm.in on tho disease was KniuM hv Mr Kirk in 1005. in consequence of mii outbreak among jmrpletr>p swedes at Bortobello. Otago. In ibis leaflet Mr Kirk remarked that tho disease was far more prevalent in tho colony than was generally supposed. Dc'-'-rilung (be trouble Mr Kirk said: •Pebiw ike crown and forming a bind oi irregular ring round the upper third, of tin* turnip arc numerous mom or loss circular depressed areas of decaying tissue varying considerably in size. They are l lght-hmwn and corky, and are generally surrounded by a welkdelined purple margin. As the disease advances these patches crack and form deep fissures which spread deeply into the interior of the turnip, complctoly ruining it. Numerous black dots <pycnidi:D now appear on the diseased patches: these dots are coneshaped and contain immense numbers of minute spores, which emerge from the apices of the fructifications in small, globular, rose-coloured masses. Tho spores then soon separate and are disseminated by various agencies, especially wind/’ As to methods of prevention it is only possible, observed tho Biologist, “to recommend those measures known to be efficacious from tho experience derived from the study of similar diseases. There seems no likelihood of being able to check tho spread of this fungus in tho bulbs themselves once they have become in. fected, but much may bo done in preventing tin* disease spreading from season to season. Great care should bo exercised in examining all roots when they are being harvested to ascertain if any show trace of diseases, and all such should at nnco bo burnt. To leave diseased roots in n field is a sure method of spreading the disease. . . .

Spraying with a suitable fungicide, such as Bordeaux mixture, might stop the disease from attacking the roots.Crops in which the presence of this phnma is suspected should bo sprayed twice—once when the plants are a few weeks old, and again when they are nearing maturity. The storage of tlio roots from diseased crops should bn carefully attended to. A thoroughly dry and well ventilated place must bo selected, for it is damp, badly ventilated situations that provide tho conditions most conducive for tho rapid spread of this fungus.’-'