Evening Republican, Volume 18, Number 76, Rensselaer, Jasper County, 30 March 1914 — UNCLE SAM, M. D. Specialist in Cereal Diseases [ARTICLE]

UNCLE SAM, M. D. Specialist in Cereal Diseases

(Prepared by the United States De part- : ment ot Agriculture.) The total annual loss from cererl diseases in the United States is estimated to be $45,000,000. Moreover, over one-half or nearly $25,000,000 of thie loss is caused by preventable diseases, remedies for which have been developed and placed in usable form for the fanners by state and federal authorities. The department of agriculture, through the office of cereal investigations of the bureau of plant industry, has specialists in grain diseases •working in laboratory, field and greenhouse in an effort to solve many scientific and practical problems of disease control which confront the grower of cereals. The state experiment stations of Minnesota, Kansas I and Washington are co-operating with the department with a view of controlling and eliminating plant' diseases that are causing such an enormous loss in the grain fields. In addition, a well-equipped laboratory is maintained at Washington, where microscopic, cultural and other studies of the disease-causing organisms are carried on during the greater part of the year. While rusts and smuts of cereals are perhaps the most widely distributed and most harmful diseases which have been studied, there is another class of “cases” which our plant doctors must now consider. These diseases are commonly called scabs, wilts, blights, and a number of other popular names. They are nearly all of them properly called soil diseases, because their spores have the power of living in the soil, as well as pn the straw, leaf or seed of their host plant. They are caused, as is the case with rusts and smuts, by parasitic fungous plants which get their nourishment from our cultivated green plants. Among the preventable cereal diseases to the stinking smut, or bunt in wheat, common in all grain-growing sections and especially troublesome in the Palouse country of the northwest, where it is harder to control, owing to the fact that it lives over winter in the soil. The estimated average annual loss is two per cent, of the crop. This emut is easily distinguished in the field when the grain is almost ripe. The smutted plants are usually slightly stunted and the heads stand more erect than the heavy, sound heads. The chaff is spread apart more or less by the dark, swollen kernels, ’giving the head an open appearance. When the tough membrane, or skin, of such a kernel ie broken, a dark, smeary, dust-like mass is disclosed which has a peculiar fetid odor like that -of de‘Miayed, fiah..„„». o L The smut can be controlled and practically gotten rid of by any one of the seed treatments which have been worked out and recommended for a number of years by the state experimient stations. Of these the formalin treatment is probably the best. There are several ways of applying this treatment It may be either sprayed on the grain or the grain may be soaked in the solution. The following method of treatment is recommended by the Washington experiment station: Construct a water-tight trough 8 feet long, 14 inches deep and 24 inches wide. Fill this two-third’s full of the formalin solution, which has been made up by dissolving one pint (a pound) of 40 per cent, formaldehyde in 40 gallons of water. Into this pour sloVly the seed wheat until the trough is nearly half full of grain. Then stir thoroughly with'a long-handle ehovel in order to float to the surface any smut balls that may have been carried in by the grain. These should be skimmed off and destroyed. Leave the grain in the solution about onehalf hour. It may then be lifted out and piled up on a granary floor or on the bottom of a wagon box and covered with moist sacks, where it is left over night. On the following morning ft will be ready to sow. If it is desired to sow’ the grain in a dry condition, it will be necessary to spread the treated seed out on the floor to a depth of two or three inches, stirring frequently in order to hasten the drying process, If the seed is sown wet, allowance should be made for its swu.len condition by getting the drill to sow a larger quantity per acre. The oat smut, another destructive disease, is widely distributed, some fields having shown as high as 30 per cent. of smutted heads. Estimated average annual loss is about two per cent, of the crop. This smut is most easily noticed a little before the grain is ripe, when smutted plants are found to be ehorter and to stand more erect than sound ones. In place of the kernels there are dark masses of smut duet which, sometimes, are covered by the chaff or glumes and sometime? are left fully exposed and are then soon

blown about by the wind, leaving the stalk of the head bare. ' , < Oat smut may be prevented by a similar seed treatment to the one given for the stinking smut of wheat. ■ There is not as much danger from smut balls remaining in the treated seed, but if any smut masses are seen they, of course, should be skimmed off and destroyed just as in the case of wheat smut. The covered smut of barley is another cereal disease with an estimated average annual loss of two per cent, of the crop. This smut is most noticeable several days after the barley has fully headed out. The smutted heads are darker in color than sound heads and the kernels are composed of greenish-black masses of smut. These are not blown away by the wind but remain until the grain is harvested and threshed, when the smutted heads are broken up. Many of the smut masses are not blown out by the threshing machine but remain with the grain, smearing it with smut The spores of the smut get on to sound seeds and are lodged in cracks and crevices of the seed coat until the seed germinates in the spring, when the young smut plant also begins to grow inside of the barley plant. This smut also can be prevented by treating the seed with formalin in the same manner as for the stinking smut of wheat and oat smut. The kernel smut of sorghum is serious in crops of kafir, broomcorn and the sweet sorghums (cane), particularly in the ari’d regions of the West and Southwest. It is not so easily observed by the farmer as are most of the other grain smuts. The young smut head takes on a gray or whitish appearance, and as it develops the smut masses in the kernels become dark brown or black. Usually smut masses are not broken and blown about to any extent in the field but remain as they are formed until harvest and threshing time. They are then broken up and the smut spores get on to clean eeeds, where they stay, just as in the case of stinking smut of wheat, until the seed is planted and the spores grow and infect the young seedlings. As in the stinking smut of wheat, careful seed treatment will kill the smut spores on the outside of the seeds. The treatment recommended is as follows: Mix one pint (one pound) of fullstrength 40 per cent, formaldehyde with 30 gallons of water and use this solution in the same manner as directed for stinking smut of wheat. The loose smut of wheat is widely distributed wherever wheat is grown. The estimated average annual loss is one per cent, of the crop. This smut is most noticeable at the heading time of the grain. In smutted heads the kernels and chaff are replaced by dark sooty masses, which are soon blown away by the wind, leaving bare stems that are usually not noticed at harvest time. The smut matures and ripens its spores when the wheat is in bloom, that is, soon after heading time. The spores do not remain inclosed by the chaff, but are loose and are immediately blown about by the wind, fall on healthy wheat heads and some of them get on to the young ovary or seed of the wheat flower. Here they germinate and send little filaments or germ tubes into the young forming kernels. As the kernels grow and en-

large tiny smut plants are formed inside of them, but remain hidden and allow the kernels to develop and fill out like other, seed. The loose smut cannot be prevented by the ordinary formalin seed treatment, as it lives over the winter inside of the seed instead of on the outside of the seed coat. The only seed treatment which has proved to be a preventive for this smut is the hotwater treatment. This is a delicate operation for the average farmer to perform, as the death point of the wheat seed itself is so close to the death point of the smut in the seed that very accurate thermometers and careful handling are necessary. The estimated average annual loss of loose smut of barley is two per cent, of the crop. The time of appearance and other characteristics of this smut are almost Identical with the loose smut of wheat described above. This smut cannot be prevented by the formalin treatment because the smut passes the winter inside the seed. , Th? hot water treatment will prevent it, but it is not recommended for the average farmer who must treat a large amount of seed in a short time at his busiest time of the year. The study of corn smut is receiving considerable attention by the department, The losses are variable, being largely dependent upon the locality and the season, but are often serious. No adequate means of control are at present available, though it is known that the losses from corn smut are less where a rotation of crops is practiced and where care is taken not to feed smutted corn tb livestock and then use the fresh manure on corn land; because corn smut spores pass through the digestive tract of farm animals uninjured and can live and multiply in the manure. Each of the cereal crops has one or more kinds of rust affecting them. The black, or stem, rusts of wheat, barley and oats are the mose serious. Each of these three crops has an early or so-called leaf rust, which nearly always is present, but seldom does serious damage. The rusts, as their name would indicate, first appear as reddish or yellowish spots on the leaves or stems of the grains. The stem rust forms long spots of this yellowish powder, which turn black as the grain ripens. It is this black rust stage with which most farmers are familiar and which they fear the most The rusts are perhaps the most serious of all cereal diseases, for no practical preventive measures are at present know, other than the use of wheats of the durum group, and the selection and breeding of new varieties reslsteht'ldrusL' No seed treatment is of any use whatever, as the rust is an external parasite, not living over in or on the seed. Neither has any spray for the growing plants been devised which results at all in proportion to the cost of its application on a large scale. In fact, experiments carried on with sprays on small plots have not given very promising results. It is hoped eventually to furnish the farmers of the great grain-producing sections with new varieties which shall be equal to the old, commonly grown sorts and, in addition, will have the added value of being immune, or at least resistant or tolerant to rust.