lo May, 1910.] 



Smut of Maize and its Treatment. 



-95 



The spores axe not only able to germinate during the same season in^ 

 which thev have been produced, but they have been kept for about eight 

 years and then thev germinated. The sprouting conidia are comparatively 

 deHcate, but they retain their germinating power for several months, if 

 kept dry. 



Infection. 



It is most important to know how infection occurs in order to^ prevent 

 it. If the spores, for instance, are on the grain and they germinate wnth 

 it, so that the germ-tube can penetrate the tender seedling, then the evident 

 course is to prevent the germination of 

 the spoTes by some " steep," as in the 

 case of Stinking Smut of Wheat. 



The first step then was tO' discover 

 how the maize plant became infected 

 and up to the present season no definite 

 answer could be given as to the modr 

 cf infection. There are at least four 

 principal modes of infection known at 

 the present time, and experiments wen^ 

 carried out tO' settle which mode occurs 

 in this smut. 



1. The most common mode is that 

 in which the voung seedlings are in- 

 fected as in Oat Smut. (Seedling 

 infection.) 



2. Another wa\ is where anv voung 

 and growing jjortion of the ho.st-plant 

 is capable of infection, as in the 

 American Corn Smut, which, how- 

 ever, is not known in Australia. (I.ccjI 

 infection.) 



3. Infection may also take place 

 through the flower and the mvcelium 

 nr spawn of the fungus lies doi'mant 

 in the ripe grain, as in Loose Smut 

 of Wheat. (Flower infection.) 



4. Infection is also known to occur 

 through the young shoots, as in Carna- 

 tion Smut. (Shoot infection.) 



To answer this question, maize was planted at the Horticultural 

 Gardens, Burnley, in a plot where this cereal had not been grown before, 

 and the variety known as Hickory King was used. Various plots were 

 sown on 5th November, 1909, in a verv dry seed-bed and each of the 

 above modes of infection was tested bv using smut-spores of the previous 

 season, which still retained their vitality. The spores were germinated 

 and fully 50 per cent, of them put forth a germ-tube which boxe conidia. 

 The plants grew in everv plot, some of them re.-iching a height of over 

 7 feet, and both flowered and fruited. 



4. SMALL COB WITH SCATTERED 

 GRAINS SMUTTED AND SMUT 

 PUSTULE ON OUTER SURFACE OF 

 ENVELOPING BRACT. (nATLIRAL 

 SIZE.) 



