Journal of Agriculture. [lo ^^Fav, 1910. 



Treatment. 



The fact that seedling infection occurs in this smut suggests the advisa- 

 bility of treating the seed, whereas in the American Corn Smut this is 

 found tO' be of no avail, since infection comes not from the seed, but 

 from conidia in the air which reach the growing plant. 



Some growers in the Lindenow district have treated the seed with blue- 

 stone at my suggestion and have stated that it reduced the .smut, but 

 definite field experiments will be undertaken, not only with bluestone but 

 Avith other fungicides and the exact result recorded. Where the seed was 

 treated with bluestone solution (Plots 6 and 7), the germination was just 

 as good as in the other plots sown Avith untreated seed and the plants 

 seemed to grow just as well and as tall. 



The following measures for dealing with this smut are .recommended : — 



1. Since infection occurs through spores carried on the seed, the 



affected plants scattered through the crop should be removed, 

 care being taken to prevent the scattering of the spares, and 

 either destroy the smutted ears h\ burning preferably, or by 

 placing them in boiling water. This is a practicable method 

 and would alone considerably reduce the amount of infection. 



2. All imparted seed should be disinfected, as the spores might 



unwittingly be conveved and sown along with it. 



T,. Seed should be treated witli a 2 ]ier cent, solution of bluestone. 

 or I lb. of sulphate of copper to- 5 gallons of water, and onlv 

 left snfticientlv long in the liquid to allow of every grain being 

 wefjed. 



A test was made oif the effect of formalin on the' germination of the 

 S|3ores. The usual strength was used, i lb. in 40 gallons of 

 water, and the spores were kept in this .solu':ion for five, ten and 

 fifteen mlinutes respe'^:iveiy. In every case the spores were 

 found to germinate, the examination l^eiiig continued for seven 

 davs, so that formalin of chis strength is not a preventive. 



II.— American Corn Smut. 



{Ust/lago zeae (Beckm.) Unger.) 



Since this smut has not hitherto been found in Australia, it will not 

 be necessary to treat it at great length. 



The smut-boils have already been .referred to and the spores are pro- 

 duced in countless myriads. These spores under favourable conditions of 

 heat and moisture and with suitable food material, give rise to germ-tubes 

 which bear numerous conidia. The conidia sprout like yeast and the 

 numerous secondary conidia, formed in this way, ar'e carried by the wind 

 or other agency to fresh plants, where infection occurs if the tissues are 

 \oung and tender. The smut-spores are likewise able to rest through the 

 winter and germinate in the spring when fresh food is available. The 



infection is purely local, and the smut-boils may appear at the point where 

 this has taken place in alx^ut three weeks ; showing how rapidly the fungus 

 can reproduce itself. While any young and growing portion of the plant 

 may be attacked, and all through the growing season, vet it is the cob 

 which most frequently suffers. The food stored up in the grains offers 

 a splendid opportunity for the fungus, and the proiluclion of spores is 

 simply enormous. 



Treatment of the seed corn with bluestone or formalin has not pre- 

 vented the smut, and all smut-linils and spore masses should be carefully 

 aemoved and destroyed, so' as to lessen the risk of fresh infection. 



