A DISEASE AFFECTING WHEAT.

Lyttelton Times, Volume CI, Issue 11887, 10 May 1899, Page 3

A DISEASE AFFECTING WHEAT.

TO THF. EDITOR. Sir,—l desire to draw your attention to the presence of a most serious disease attacking wheat, noted by a Waunate farmer some six years ago and which, in.his wo to rime "now, "“ is increasing every year.” I now had a .pecimen orwarded to me from a Canterbury farmer about twelve months ago. 1 am not aware «f its having previously been recorded in New Zealand, but ')i’ cc I would point out the urgent necessity f such steps being taken as wil hasteu its eradication. A diseased sample was tor to Mr M'Alpine, of •; identification. It is the also called ” purples, or poppercorn of wheat, oats, and other grasses ; the lylen chus tritici of Bastian. c «movliat The life histoiy of the pest as follows:—A small thread-like ie Sole Term, about the mtl. ot «n >nd.long, crawls up th. stalk mi U» » ow " ing iiead of, ray, wheat. There it punctures the, central part of the, °™ ei ” . so irritates the plant that an unusual flo of sap results, which finally g'ves. mo to the - development of a gad ti „ B tinv worm. As a consequence we find the grain of wheat -replaced by a . ■ b A^ k ‘ coloured “ gall,” a little over half the size of a healthy grain. will contain half these galls and half t ood wheat grain. In this gall , the female her emus. These hatch in about fourteen days, and the resulting worms are so crowded together as to fill the interior of each black gall with a cotton-looking mass of male and female worms in all stages of growth. Here also pairing takes place, tor the .sexes are quite distinct. If, now, one of these galls be sown along with a healthy gram, the black wall ol tne gall softens and decays, setting free thousands of youn o, worms, each one (excluding males) ready to produce little galls containing more thousands of young. The little worms have been known to live after a death-like sleep of twenty-seven years inside the gall. . ~ ' If a bit of the white mass inside b.; placed in a drop of Slightly warmed water and examined, with a good magnifying glass, a tangled, seething mass of worms can be seen gradually wriggling themselves free. It is hardly pleasant to .contemplate these objects ground Up with flour; especially is this so when one considers how horribly like unto flour do the contents of each gall appear to tire naked eye. The following is from the “ Australasian,” April 29. From' the nature of the disease preventive measures alone can be attempted:—“l. The galls should be separated from the seed wheat, as'it has been proved that the galls can infect sound grain. (2)'"All galls should be' carefully gathered and burnt, for the worms may revive even after lying dormant for over a quarter of a century. 3. The ear cockles are often blown over with the chaff,, so it should be burnt as well. 4. Top-dress-ing of the land with a mixed manure, such avkainit, nitrate of soda, superphosphate of lime, and salt, has been found beneficial in infested soil. 5. As moisture is necessary for the activity'of these thread worms the land should be well drained.”

The life history of the worm requires to be further investigated, but a good account will be found in Smith’s “ Diseases of Field and Garden Crops ''; and of some closely related varieties by Cobb, in the “Agricultural gazette' of New South Wales,” Vol. I. The worm, specimens of diseased grain, etc., can be seen in the Biological Laboratory of the Canterbury Agricultural College.—l am,, etc., J. W. MELLOR, Lecturer on Natural Science. Agricultural College, Lincoln, May 6, 1898. ■’