LOSSES CAUSED BY FUNGUS

Southland Times, Issue 23816, 13 May 1939, Page 18

LOSSES CAUSED BY FUNGUS

Ryegrass Crops In

Southland

RESULTS OF LATEST RESEARCH

During the last season the losses suffered by Southland farmers because of attacks on ryegrass crops by fungus crops reached serious proportions. The attacks were heaviest on the true perennial strain of certified ryegrass, many of which had a very low germination response when placed under test. The ordinary Southland strain was also badly affected by the unusually wet conditions during the ripening period, this variety being fairly generally immune from the complaint. The failure of certified ryegrass seed grown in the south to give a good germination respqjise has caused farmers in this province a good deal of concern, because it has prevented them from recovering the important trade in seed production. At one time Southland produced a considerable percentagei of the ryegrass seed grown in New Zealand, but the discovery about 10 years ago that the Hawke’s Bay strain was of superior carrying capacity gave the southern farmers a serious set-back. Many of them decided that they would renew their pastures with the Hawke’s Bay variety and so recover the seed trade, but the germination results from Southland-grown seed have frequently been so unsatisfactory that very little business has been done. Wet seasons experienced in the province have been disastrous for the seed grower as perennial ryegrass appears to be particularly susceptible to the attacks of fungi. Inland districts of the province have not fared so badly in previous years, but all parts of the province have suffered during the last season. The seed is most frequently affected in some parts of New Zealand with ergot, a fungus which distorts the shape of the seed and turns it black and hard. If the seeds affected with this fungus are eaten at one stage of their growth by cattle, the ergotin which they contain causes abortion and often a sloughing of the extremities—the hoofs, horns and sometimes the end of the tail At its snore-producing stage, when the ergoted seed is lying on the ground surface and the fungus is stimulated to growth by the warm autumn rains, ergot is also suspected of causing serious losses of lambs through its effect in promoting abortion among ewes. “BLIND SEED DISEASE” Recently a study of a further fungus affecting ryegrass and called “blindseed disease” by the investigators, Messrs J. C. Neill, mycologist to the Plant Research Bureau, and E. O. C. Hyde, seed analyst of the Department of Agriculture, Palmerston North, has been made, and their findings are fully reported in the February issue of The Journal of Science and Technology. A further and somewhat similar fungus associated with ryegrass is also described under the name of “Lolium Fungus No. 2.”

The effect of the blind-seed disease fungus is to prevent the proper development of the seed when it is attacked in the earlier -stages of its development, and to kill the germ in that affected when nearer maturity. Often, affected seed will have germination figures of less than 20 per cent., and it, therefore, makes the grass seed crop quite unprofitable to harvest, and the seed practically useless to sow. Unfortunately the appearance of 1 a sample of cleaned and dressed seed affords no indication of the extent to which it may be affected by blind-seed disease. Outwardly these seeds are indistinguishable from healthy seeds, and a heavily-infected sample may appear plump and bright and of good bushel weight. Only when tested for germination is the incidence of infection discovered.

A service has been established by the seed analyst whereby growers may send samples of immature heads for examination and report on the estimated infection of the crop when, if the florets prove to be badly affected and not worth harvesting, (he grower may use the crop for hay or for grazing. So far no method of control of this disease has been discovered, but • the investigators are hopeful of discovering a type of ryegrass resistant to the attacks of the fungus.