nmm sP

More documents

Recommendations

Info

$WI LD R LATI\IES CROP PLANTS IN INDIA$

$~\\~SAnfF~~~ ,$

46 THE BRITISH SMUT FUNGI Wilkinson & Kent (1945) used 0-7 per cent, triethanolamine oleate to reduce the surface tension. The development of galls in artificially inoculated maize may be inhibited by certain bacteria antibiotic to smuts in culture (Johnson, 1931; Bamberg, 1931). Modifications of the hypodermic injection method have been used for bunt of wheat, the loose smuts of wheat and barley, and loose kernel smut of sorghum (Fans & Reed, 1925; Milan, 1928 ;.Bodine & Durrell, 1930; Lange de la Camp, 1936, 1940). Suspensions of germinating chlamydospores, or mixed sporidia from appropriate cultures, form the inoculum which must be inserted near meristematic tissue. Chlamydospores of U. striiformis, injected as near as possible to the apex of shoots of Poa pratensis, gave good infection, and the method is likely to be useful in breeding for resistance to stripe smut (Leach, Lowther, & Ryan, 1946). The use of low temperatures and artificial illumination to extend the season for experimental work on smuts deserves further study, since the results are somewhat conflicting. Lengthening the period of light gave a marked increase in the percentage bunt in two varieties of spring wheat (Rodenhiser & Taylor, 1940) and caused a breakdown in the resistance of another variety to some races of bunt (Rodenhiser & Taylor, 1943). A small increase in the amount of smut on Dakold rye occurred under long day conditions (Ling, 1941), but artificial illumination failed to alter the degree of infection by smut on oats (Reed, 1938). Snell (1938) found that early varieties of summer wheat could be tested for bunt resistance in six weeks by maintaining a temperature ofl6°-17° C. during germination, and 20° C. during subsequent growth and constant (day and night) illumination. VemaUzed winter wheat may give a lower bunt infection than the control seed (NemUenko, 1935; Lasser, 1938). Marquis wheat artificially inoculated with loose smut gave the same incidence of disease when vernalized and not-vernalized (Hanna, 1936). Bever (1947) used vernalized seed and grew two experimental crops of wheat in one year in his work with loose smut. CONTROL (a) To determine the smut spore load on cereal seed. Forty gm. of seed are placed in a 500-ml. Erlenmeyer flask to which 60 ml. of distilled water containing 0-1 per cent, of a proprietary wetting agent are added. The flask is then shaken vigorously 30 times, taking care to overturn thoroughly the seeds in the flask. Ten ml. of the washings are immediately poured into a centrifuge tube, centrifuged for four minutes at 2,400 r.p.m., and the supernatant liquid is then siphoned off to within 0-3 ml. To this residue is added 0-2 ml. of a 4 per cent, gelatine solution maintained at 45° C, making a total of 0-5 ml. of spore suspensions. The spores are dispersed by stirring and a loopful is withdrawn quickly and placed on a special slide and immediately covered with a cover glass. If smut spores are numerous, count eight microscopic fields, if scarce, eight swaths, across the central square of the slide. In order to compute the spore load of the grain sample, the counts are compared with standards prepared from artificially smutted grain samples carrying a range of known spore loads (Cherewick, 1944; •BusseU, 1946). (6) Seed treatments. Historical reviews have been given by Woolman & Humphrey (1924), Sampson & Davies (1925), Koehler (1935), Dillon Weston
TECHNIQUE 47 (1939), Holton & Heald (1941), and Buttress & Dennis (1947). Holton & Heald (1941) give references to over 200 different substances which have been tested for the control of bunt. They also review in some detail the laboratory method first introduced by Gassner (1923) for determining the chemotherapeutical index of fungicides. Seed treatment when infection comes from spores carried on the seed. Formaldehyde. Grain is sprinkled with a solution made by mixing one part of 40 per cent, formaldehyde (formalin) in 320 parts of water and covered for two to four hours before it is spread out to dry. From one to two gallons of the solution is required to moisten four imperial bushels of grain. Injury to germination sometimes follows, especially in wheat if the pericarp lying over the embryo is cracked (Hurd, 1921). Grain should be sown within a few days of treatment (Moore, 1945; Dillon Weston & Taylor, 1948). This method is particularly useful for small lots of grain to be used in laboratory experiments requiring smut-free seed. If the seed is to be reinoculated, it is washed in running water for 30 minutes before drying. • Dusts are now preferred for treating grain in bulk. Dusts. Copper carbonate applied usually at the rate of two ounces per bushel is effective for the control of wheat bunt provided the grain is not too heavily contaminated with spores. It is less effective than organo-mercury compounds for other seed-borne diseases of cereals, and has been superseded by proprietary products which are sold under trade names such as Uspulun, Semesan, TUlantin, Ceresan, Agrosan, &c. The ingredients of these dressings vary widely (Dillon Weston & Booer, 1935; Martin, 1940) and under a scheme initiated in 1943 those tested and approved by the Ministry of Agriculture bear a special diamondshaped mark (Dillon Weston & Taylor, 1948). To treat small samples of any cereal with either copper carbonate or one of the organo-mercury dusts it is only necessary to shake the grain with some of the powder and to remove the excess by sieving, but for treatment on a larger scale special machines must be used. These vary from hand-rotated chums to more elaborate power-driven machines (Holton & Heald, 1941; Moore, 1945; Dillon Weston & Taylor, 1948). Organo-mercury dusts are poisonous and should not be inhaled or handled with wet hands. In the slurry method of treating seed flying dust is eliminated. The fungicide, in a wettable form, is applied to the seed in a heavy suspension which leaves only 0-5 to 1 -0 per cent, of moisture on the seed and this soon evaporates (Leukel, 1948). In Britain some growers make a practice of applying an organo-mercury dust to seed oats, wheat, and barley before dispatch. Treated grain can be stored for months in a dry, cool, and wellventUated place and the chemicals are said, to deter rodents. Injury does not follow unless the seed is damp when treated and excess adheres to the seed or if seed has been mechanically injured in thrashing. Seeds may be killed outright or grow with abnormally thickened and much-stunted shoots and roots (DiUon Weston & Brett, 1944; Moore, 1945; Hoppe, 1948). Organo-mercury dusts owe some of their popularity to the fact that they exert a fungicidal action against some other pathogenic fungi such as Helminthosporium avenae and tend to promote good estabhshment in the field (Sampson & Davies, 1925, 1926; Muskett & Cairns, 1932; Moore, 1945). They have been recommended for the control of Ustilago bullata in forage grasses which are liable to suffer injury from formaldehyde (Moorwood, 1935; Fischer, 1942).
Page 1 and 2: THE BRITISH SMUT FUNGI ^ (USTILAGIN
Page 3: FOREWORD THIS volume was started wh
Page 6 and 7: 6 PBEFACE We also acknowledge the b
Page 9 and 10: INTRODUCTION THE smut fungi, which
Page 11 and 12: INTRODUCTION H of bushels of wheat
Page 14 and 15: FIG. 1. Vstilago avenae on Arrhenat
Page 16: ^^ THE BBITISH SMUT FUNGI Young hea
Page 19 and 20: BIOLOGY 15 less than the normal, in
Page 21 and 22: BIOLOGy 17 and united with it, fina
Page 23 and 24: BIOLOGY 19 eermination in a collect
Page 25 and 26: BIOLOGY 21 genus, and the manner of
Page 27 and 28: BIOLOGY 23 species of Entyloma, and
Page 29 and 30: 3036^ BIOLOGY 25 in others. Dickins
Page 31 and 32: CYTOLOGY THE discovery of nuclei in
Page 33 and 34: GENETICS INCOMPATIBILITY KNIEP'S di
Page 35 and 36: GENETICS • 31 direction of growth
Page 37 and 38: GENETICS 35 when a few sporidia fro
Page 39 and 40: GENETICS 37 lines retained their di
Page 41 and 42: TECHNIQUE COLLECTION AND EXAMINATIO
Page 43 and 44: TECHNIQUE 41 be undesirable. Weak a
Page 45 and 46: TECHNIQUE 43 in one season (see p.
Page 47: TECHNIQUE 45 barley with loose smut
Page 51 and 52: TECHNIQUE 49 Allen's, modification
Page 53 and 54: CLASSIFICATION THE morphological ch
Page 55 and 56: THE BRITISH SMUT FUNGI MOST of the
Page 57 and 58: FIG. 2. Spore geimination in Ustila
Page 59 and 60: THE BRITISH SMUT FUJJGI 57 from one
Page 61 and 62: THE BRITISH SMUT FUKGI 59 of exsert
Page 63 and 64: THE BRITISH SMUT FUNGI 61 noticeabl
Page 65 and 66: THE BRITISH SMUT FUNGI 63 Evidence
Page 67 and 68: THE BRITISH SMUT FUNGI 65 winter in
Page 69 and 70: THE BRITISH SMUT FUNGI 67 Ustilago
Page 71 and 72: THE BRITISH SMUT FUlJGI 69 material
Page 73 and 74: THE BRITISH SMUT FUNGI 71 results o
Page 75 and 76: THE BRITISH SMUT FUNGI 73 TTstilago
Page 77 and 78: THE BRITISH SMUT FUNGI 75 Species i
Page 79 and 80: " TJSE BRITISH SMUT FUNGI 77 Ustila
Page 81 and 82: THE BKITISH SMUT FUNGI 79 On Carex
Page 83 and 84: THE BRITISH SMUT FUNGI 81 Exsiccati
Page 85 and 86: THE BRITISH SMUT FUNGI 83 Tilletia
Page 87 and 88: THE BRITISH SMUT FUNGI 85 bunt ball
Page 89 and 90: THE BEITISH SMUT FUNGI 87 globose t
Page 91 and 92: THE BRITISH SMUT FUNGI 89 FIG. 13.
Page 93 and 94: FIG. 15. Spore geimination in Taboi
Page 95 and 96: FIG. 17. Spore germination in Urocy
Page 97 and 98: THE BRITISH SMUT FUNGI 95 separate
Page 99 and 100:
THE BRITISH SMUT FUNGI 97 8ori in t
Page 101 and 102:
THE BRITISH SMUT FUNGI 99 Urocystis
Page 103 and 104:
30390 THE BRITISH SMUT FUNGI 101 pr
Page 105 and 106:
FIG. 20. Spore geimination in Entyl
Page 107 and 108:
THE BRITISH SMUT FUNGI 105 Sori in
Page 109 and 110:
On Ranunculus ficariae and B. scler
Page 111 and 112:
THE BRITISH SMUT FUNGI 109 Infectio
Page 113 and 114:
THE BKITISH SMUT FUNGI 111 [Sporidi
Page 115 and 116:
THE BRITISH SMUT FUNGI 113 Ustilago
Page 117 and 118:
REFEEENCES 115 BBETT, M. A. (1940).
Page 119 and 120:
REFERENCES 117 ^ DniON WESTON, W. A
Page 121 and 122:
REFERENCES 119 GRIFFITHS, MAEIOK A.
Page 123 and 124:
REFERENCES 121 HtjTTiG, W. (1933).
Page 125 and 126:
REFEBENCES 123 LiMBOtruN, E. J. (19
Page 127 and 128:
REFERENCES 125 NOBLE, E. J. (1934).
Page 129 and 130:
REFERENCES 127 RoDENHiSEE, H. A., &
Page 131 and 132:
BEFERENCES 129 STAKMAK, E. C, XCEEN
Page 133 and 134:
EEFEEENCES 131 WAXTBE, J. M. (1934)
Page 135 and 136:
INDEX to generic and specific names
Page 137 and 138:
Muscari Ustilago vaillantii, 59 Myo
Page 139 and 140:
Ustilago ficuum Reich., 113 —flps
Page 141 and 142:
2i}:y0 ANDHRA PRADESH AGRICULTURAL
show all

nmm sP

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?