A DISEASE AFFECTING WHEAT.

Otago Witness, Issue 2360, 18 May 1899, Page 6

A DISEASE AFFECTING WHEAT.

A TIMELY WARNING

Mr J. W. Mellor, lecturer on natural science at Lincoln College, writes to the Chrislchurch Press as follows: —

I desire to draw your attention to tho presence of a most serious disease attacking wheat, noted by a Waimate farmer some six years ago, and which, in hiswords to ma now, "is increasing every year." I alsc had a specimen forwarded to me by a Canterbury farmer some 12 months ago. I am not aware of its having previously been recorded in New Zealand, but once here I would point out th« urgent necessity for such steps being taken as will hasten its eradication. A diseased sample was forwarded to Mr M'Alpine, of Victoria, for identification. It is the " ear cockle," also called "purples" or "peppercorn" of wheat, oats, rye, and other grasses; the Tylenchus tritici of Bastian.

The life history of the pest is somewhat as follows: A small, thread-like female worm, about one-sixth of an inch long, crawls up the stalk, and reaches the flowering head of, say, wheat. There it punctures the central part of the flower. This so irritates the plant that an. unusual flow of sap results, which finally gives rise to the development of a gall, enclosing the tiny worm. As a consequence, we find the grain of wheat replaced by a blackish-coloure<J " gall," a little over the size of a healthy grain. Sometimes an ear will contain half of these galls and half good wheat grain. In this gall tho female lays her eggs. These hatch in. about 11 days, and the resulting worms are so

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crowded together as to fill the interior of each } 29, 1899: — "From the nature of the disease black gall with a cotton-looking mass of male preventive measures alone can be attempted. siss^s: as Sftiss Six •\ »• *-» be -*-?£?£• -? distinct. If now, one of these galls be sown wheat > as at nas been Proved that the galls " along with a healthy grain, -the black wall of can mfect sound wheat. 2. All galls should he "the gall softens and decays, setting free thou- carefuu y gathered and burnt, for the worms sands of young, each one (excluding males) ' may revive even a i ter lying dormant for over a:eady to produce little galls containing more a <l uart er of a century. 3. The ear cockles are thousands of young. The little worms have °ft en blown over with the' chaff, so that it ■fceen known to live after a death-like sleep of should be burnt as well. 4. Top-dressing of B7 years inside the gall. , the land with a mixed manure, such as kainit, If a bit of -the white mass inside be placed nitrat « of soda, superphosphate of lime and an a_ drop of slightly warmed water and ' Ba^> .^ een f° un^ beneficial in infected soil, examined with a good magnifying glass, a &. As moisture is necessary for the activity of tangled, seething mass of worms can be seen these thread-worms, the land should be well I?raaually wriggling themselves free. It is drained.' " faardly pleasant to contemplate these objects The life history of the worm requires to be • ground up with flour; especially is this so further investigated, but a good account will -wnen one considers how horridly like unto be found in Smith : " Diseases, Field and Garilour^aoes the contents of each gall appear to den Crops " ; and of some closely related Th/ fnil ey - 6'6 ' • * - . varieties by Cobb in the " Agricultural Gazette Ahe following is from the Australasian, April of New South Wales," vol. 1.