RYEGRASS FUNGUS

New Zealand Herald, Volume LXXVI, Issue 23338, 5 May 1939, Page 16

RYEGRASS FUNGUS

germ in seed killed NO OUTWARD INDICATION experiments in dominion by oumniK Perennial ryegrass (lolium pcrenne), probably the most widely sown of any of the introduced pasture grass specie® in New Zealand, appears to be particularly susceptible to the attacks of fungi. Of all the grasses, excepting perhaps tall fescue, its seed is most frequently affpcted 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 spore-producing stage, when the ergoted seed is lying 011 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 e\j,'es. j Effect on Germination Recently a study of a further fungus affecting ryegrass and called "blind-seed disease " by the investigators, Messrs. J. C. Neill, mycologist of the Plant Research Bureau, and E. 0. C. Hyde, seed analyst, 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 siiyilar fungus associated _ ryegrass is also described under the name of "Lolium Fungus No. 2." Tlio 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. Service for Growers Unfortunately the appearance of 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, the grower may use the crop for hay or for grazing. So far no method of control of this disease has beeii discovered, but the investigators are hopeful of discovering a type of ryegress resistant to the attacks of the. fungus.