172 Journal of A^^ncuUiirc. [10 March, 1909. 



although spores of the smut mav be in the soil from a pre\ious crop or 

 fiom self-sown wheat. Then the farmer almost invariably upsets any 

 answer vou may gi\'e bv adding that the next season things were reversed, 

 the clean part of the paddock being smutted and the other not, even 

 with the aforesaid proper treatment. Bearing in mind that there is no 

 fungus disease known which can be mor<- readilv or more ab.solutelv pre- 

 vented than this smut, we will n<)w j>r()]i(iuiid a few of the questions which 

 arise in connexion with it. 



First of all we mav state delinitelv that the smuts of wheat, oats, and 

 barley are not the same. Xo, thev are quite distinct ; for the smut of 

 wheat cannot infect oats or barlev, nor can the smut of oats or barley infect 

 each other or the wheat. 



1. TI'V/r docs binit sometimes appear in a paddock 7clieii tlie seed is- 

 supposed to be properlx treated? 



This may be due to various causes, such as returning the treated grain 

 to bags which have not been disinfected and thus re-infecting the grain, or 

 sowing the seed with a drill which has not been properly cleaned. It may 

 be, however, that the smut-balls had not been skimmed off in the process 

 of pickling and being crushed in the drill the seed is infected. 



2. Will the bunt spread from one paddock to another, or from one plant 

 t,- another, like the rust, :.dien the crop is groivingl- 



Since infection occurs in the .seedling .stagt only and the germ-tubes^ 

 penetrate at the ix>int where stooling occurs, and that is beneath the ground 

 when the grain is covered with earth, there is no possibilitv of the disease 

 spreading from one growing plant to another. 



3. Should seed-wheat be used from a crop known to he buniid'l 

 Decidedlv not, for there is a strong probability that the grain will not 



be so plump as if perfectly healthy. A crop may have but comparatively 

 few actuallv smutted ears and vet give a much reduced yield and a poor 

 qualitv of wheat, because the smut was in the straw and affected the yield,, 

 although it did not reach the ears before maturity of the grain. 



4. Will spores lying on or in the ground from last year's crop infect 

 the next 'i 



This question of infection from the soil often crops u]). luit since it 

 was found by rej^eated experiments that [jrojx^rlv treated grain, evert 

 although grown on verv smuttv ground, was free, it may be concluded 

 %at soil -in feet ion practically does not exist. I say practically because there 

 xs a possibilitv of stray infection taking place when there are numerous 

 spores around the germ end of the see(l where the young plant bursts 

 through . 



5. Ma\ bunt originate from self-sown wlieatl 



Self-.sown wheat is rarelv affected by bunt; still it may occur in some 

 .seasons. I have usually seen self-sown crops perfectly free and have al.sO' 

 found a little, but not in sufficient quantity to injure the sale of the 

 wheat. It is generally stated that it is the heat of the sun in summer 

 which kills the bunt spores on self-sown wheat ; but Farrer showed that 

 the rains and the dews may also cause the spores to germinate and having 

 no germinating wheat plants to penetrate, they soon perish. The heat of 

 the sun and the dews at night are likely to prevent the apjiearance of 

 bunt in a self-sown crop, but if the interval between the harvesting of the- 

 crop and the sowing of the next, as \wl1 as between the ploughing of the 

 land and the seeding is short together with cool and dry weather, there 

 may be some danger of infection. In the early days many farmers used' 

 10 expose on a cloth the wheat intended for next year's seed. They found 

 that the weather — dews, sunlight, and hot dry winds — acting on the .seed" 

 for a period of several weeks, killed the sjiores, or rather they discovered' 

 that it gave a clean crop, without knowing the reason why. 



