BED BUST IN WHEAT.

Southland Times, Issue 1017, 7 September 1868, Page 3

BED BUST IN WHEAT.

(From the " Farmer.")

Having recently received some letters from Australia, inquiriug "■ whether the red rust, which injuriously affects the growth of wheat and other cereals, as well as pasture grasses, is a vegetable fungus, produced by atmospheric influence, or an insect parasite ? " we have to state that it is a vegetable belonging to the lowest tribe of fungi, in which are associated those most minute and destructive vegetable parasites known as rust, blight, mildew, smut, &c, which, although not produced by atmospheric influences, are yet greatly dependent upon them for their devastating extension, or restriction within harmless bounds. Much uncertainty still exists in regard to the production, characteristics, and habits of these minute members of the vegetable kingdom, as well as in regard to the changes which they undergo in different stages of their existence. Thus the linear red-rust — TJredo linearis — . of some authors, is held by others to be identical with Puccinea graminis, or wheat mildew, in its earlier stages, or before it becomes changed in color and formation by age. The true red-rust, red-gum, or red-robin of agriculturists is termed Uredo rubigo, and appears in the form of reddish or orange colored powdery spots on the leaves, stems, and inflorescence of graminse, especially wheat, in the glumes or chaff of which it is frequently present without injuriously affecting the grain. The anthers of the wheat flowers, when arrested in their growth by the wheat midge,- as well as the young larva of that minute but destructive insect, are not unfrequently mistaken for red-rust by superficial observers.

In walking through rust infected fields of wheat, oats, and hay grasses, between the period when their young leaves first cover the soil, and that" when the young ears make their appearance, the boots, provided the foilage is dry, may be seen covered with a reddish brown or deep orange-colored dust, which, on examination, will be found to have proceeded from either linear or roundish minute patches on the leaves — frequently only one of these forms being present, and occasionally both. But so little is this rusty appearance dreaded by British farmers, that we have heard some assert that they looked upon it as beneficial rather th"an otherwise, and that such rust coloring of their boots almost invariably preceded a good wheat crop. In Australia, the Cape of Good Hope, and some parts of Continental Europe, as well as in other wheat-producing countries, the red rust is, however, by no means so innocuous, and it is there looked upon as one of the moat disastrous of field scourges. "We have frequently grown samples of wheats from these countries, as well as from Northern India, South Africa, and the shores of the Black Sea, among which some were so rust-infected that a sufficiency of perfect seed could scarcely be got to perpetuate the kinds; but even with the worst of these the rust became much less virulent in the second year, while in the third and succeeding years it either entirely disappeared, or became so mild as to be almost harmless. It is always dangerous to found definite theories upon imperfectly authenticated observation and experiments connected with the lower orders of cryptogamic vegetation ; but these results, seem to indicate that the red rust is capable of being transmitted to distant countries with the seed, and that our climate is not suited for the malignant development of the red rust disease. It may also be here remarked that neither the different races or species of wheat, nor their varieties, were affected with equal severity, but those of the beardless Triticum hibernicum generally suffered least. The strong-growing bearded turgid wheats (T. turgidum) Buffered rather more, the varieties of the bearded spring wheat (T. festivum) to a much greater extent, and those of the hard finely-grained (T. durum) were generally the worst of all. It is generally remarked that dry cold weather, which retards the growth of the young grain and grass plants, is that in which the red-rust appears most abundantly ; that plants grown upon soils in which salt is deficient are more susceptible to its attacks than others, and rank manures are also favorable to its production, it being almost invariably worst in plants growing upon the old sites of dunghills and other over-enriched places. Had British farmers suffered as much from red-rust as they at one time did from that other minute wheat-deteriorat-ing fungus, the TJredo caries, which is known in different localities as bunt, smut, or blackball, they would, doubtless, have long since discovered equally efficacious steeps or other remedies for its prevention or cure. Australian Colonists and others who really suffer severely from the red-rust, will do well to intimate that perseverance in the search for remedies, which enabled Home growers to combat so successfully against a no less insidious and hurtful enemy.

Some of the foregoing remarks may prove useful in indicating effectual modes by which the rust plague may be overcome, such as the application of salt as a manure iv places remote from the sea, the sowing of clean or uninfected seed, and its disinfection by steeps and other applications, among which that of sulphur, either in mixture for a considerable time before mowing, or as a semi-adhesive coating to the grains, is suggested, from its well-known destructive effects upon other minute parasitical fungi