COCKSFOOT PEST

Press, Volume LXXIII, Issue 22004, 30 January 1937, Page 17

COCKSFOOT PEST

SERIOUS DAMAGE TO CROPS

INVESTIGATIONAL PROGRESS

Cocksfoot growers are very much concerned this season' at the appearance of an unidentified disease in their crops. The trouble is reported to be worse on the Plains than on the Peninsula, but it is general, and estimates have placed the reduction in the seed output as a result of it at 50 per cent. In some cases, indeed, the loss is expected to be much larger. Naturally the severity of the trouble has set afoot investigations as to the cause of the disease, and Messrs J. W. Calder (field husbandry officer at Lincoln College), and his assistant, Mr I. D. Blair, have been working on the problem., Mr Blair supplies the following as a result so far of his investigations:— With regard to the symptoms of the disease it seems that there are two conditions:—First, the seed heads, though normal in size, usually contain small or shrivelled seeds and exhibit varying degrees of sterility. Second, there is a stem blight characterised by the presence of small, circular brown lesions on the upper part of the stem and branchlets of the seed head. These latter signs of the disease are not present when the crop is coming into ear but appear and increase in severity as the crop matures and ripens. Presence of Insects

A number of growers have noticed small insects in seed samples harvested from affected crops. They suspect these as being responsible. It is known that a number of insects, including the grass thrip, may be found on the seed heads of most grasses. They suck the sap of the plant in the region of the developing seed but it is only when present in very large numbers that they cause damage to seed crops by preventing the seed from developing. At an earlier stage they may actually prevent the seed from setting by destroying the flowers. An enquiry made with the authorities at the Imperial Bureau of Plant Genetics at Aberystwyth, Wales, produced the information that the only insects which were known to cause significant damage to cocksfoot seed were three species of gall midges (quite distinct from thrips). An examination of several local lines of affected cocksfoot has failed to reveal these gall midges. Thrips have been found but unless they are present in very large numbers they are not likely to cause appreciable damage. All the thrips in New Zealand are introduced —there are no native species. If these species are not destructive to cocksfoot in England, they are not likely to cause damage here.

A more likely cause may be found associated with the diseased stems described above. During an investigation of this stem blight condition at the college, a number of fungus organisms have been isolated. At least two of these are known to belong to families which are parasitic on plants. Further work is being conducted to find which ones are actually responsible. The infection of the stems is external in origin. The diseased areas are found only on exposed portions such as the upper stem. There is no sign of it where the stem is protected by the enfolding leaf sheaf. Also microscopic examination shows that the infection first of all causes death of the outer green cells of the stem. It may affect the inner conducting tissue later, thus blocking the passage to the seed heads and causing the light seed yields which are being reported. If this supposition of infection by wind-borne fungi is tenable it is possible that spraying or dusting may protect the plant from infection. Spraying’ Results One grower is so convinced of the severity of the disease that _ he has sprayed his crops this year with a lime sulphur mixture. He is of the opinion that this treatment, although not strikingly effective, has been worth while. The spraying was performed well after the heads had appeared and he intends to spray earlier next year. The effect of spraying at different times will be examined for there seems to be a definite period of susceptibility. Preliminary trials in spraying at different times were carried out at the college this year, but the results were not conclusive. A more extensive trial is being planned, based on the experience we have already gained. The matter is of interest to all growers, but is still in the stage of critical investigation. Those who are interested and who can offer relevant information are invited to communicate with Mr Blair, at the College.

SMITHFIELD FAT

STOCK SHOW

SUCCESS OP SUFFOLK CROSS

A report just to hand shipws one© again that in carcase competitions the Suffolk and its crosses are at the top of the tree. So much is this the case that there is a class provided for any crossbred carcase from which the Suf-folk-Southdown cross alone is excluded, a practical admission that for super quality meat this cross is in a class by itself. As there are some 25 separate breeds in Great Britain from which about 500 crosses could be made this is a marked distinction. In the carcase competition confined to the Suffolk-Hampshire and Oxford Downs, the Suffolk was placed first, as usual. •

AUSTRALIAN HARVEST

REDUCED CROP

A final estimate, made by the Commonwealth Statistician indicates that the 12,609,000 acres under wheat in Australia during 1936-37 will yield 134,182,000 bushels.

Despite the cultivation of 684,000 acres more than for the previous season. the yield, according to the official estimate, will be 8,400,000 bushels, or 6 per cent, lower than that for the 1935-36 season.

The Australian output, however, will represent a substantial proportion of

the world production, which is estimated at 3.304,000.000 bushels by the International Institute of Agriculture. A statement made available by the Commonwealth Statistician fixes the yield from New South Wales at 45,500.000 bushels: Victoria. STjOO.CSO; South Australia, £23.600,000; West Australia, 19,800,000; Queensland. 2.250.000 and Tasmania and the Federal Capital Territory. 470,000 Apart from a substantial decline c& last season, the nroductioa for 1936-37 will be 29,500,000 bushels, or 12 per cent, lower than the average for the 10 seasons ended in 1935-36.

The average yield an acre in all Australian States is estimated at:—Sew South Wales, 11.05 bushels: Victoria, 15.00: Queensland. 6.72; South Australia, 9.17; West Australia. 7.9. and Tasmania, 21.5.