DISEASES AND PESTS OF THE MAIZE CROP 409 



363. " White Rust" or " Blight".— In certain seasons the chap. 

 maize crop in some localities is affected by a disease which X ' 

 causes the plants to " whiten " and wither off prematurely as 

 though frost-nipped ; sometimes it .becomes so serious that a 



large part, or it may be the whole crop, is lost. This trouble 

 has been reported from the Transvaal, Orange Free State, 

 Natal, and Rhodesia, under the name of " white rust " or 

 "blight". Some farmers consider certain breeds to be more 

 susceptible than others ; inquiry shows, however, that in some 

 cases Hickory King was affected and Iowa Silver-mine or Yellow 

 Horsetooth on the same farm appeared to be less susceptible, 

 while in other cases Iowa Silver-mine suffered and Hickorv 

 King was not affected. Whether this disease is due to fungus 

 or bacterial causes does not appear to be yet known ; the 

 writer has observed that somewhat similar symptoms are some- 

 times produced by drought, and disappear when the crop has 

 been irrigated. If drought should prove to be the cause of 

 white rust, the incidence of the disease as referred to above 

 would be explicable ; the varying conditions of the soil might 

 easily account for one field being affected while another, per- 

 haps carrying a different breed of maize, remained healthy. 



The occurrence and serious nature of this disease in Rho- 

 desia were referred to by Mr. Odium (4) in 1906, but he does 

 not explain the cause of the trouble. He suggests, however, 

 as a remedial measure, the breeding of " blight-resistant " 

 strains ; if drought is the cause, the breeding of " drought- 

 resistant " strains would probably assist in some measure. 



364. Maize Smut or "Brand". — This fungus parasite, 

 Sorosporium reilianum (Kfihn) McAlp., 1 is conspicuous in 

 one stage of its life-history as large, black, sooty masses on 

 the tassel (Fig. 1 $7) or the ear (Fig. 1 58) ; when it occurs on the 

 leaves it appears generally in the form of black streaks. How 

 long maize smut has been known in South Africa is not clear, 

 but its occurrence in the Cape Province was commented on in 

 June, 1906 (Anon., 3). It is now a familiar phenomenon to 

 almost every farmer throughout South Africa ; the microscopic 

 fungus-plant lives as a parasite within the tissues of the maize 

 plant, and is only seen by the ordinary observer when it breaks 



' Also known as Ustilago Maydis (DC.) Corda, and Ustilago Mays-zea- 

 Magnus (Evans, 1). 



