DISEASES AND PESTS OF THE MAIZE CROP 415 



367. Dothiorella. — A disease of maize is recorded as oc- 

 curring in Cochin China, caused by a fungus of the genus 

 Dothiorella (Foex and Berthault, 1 ). 



368. Burr ill's Bacterial Disease of Dent and Sugar Maize. 

 — A bacterial disease is reported as affecting the roots of young 

 maize plants in some parts of the United States, but the writer 

 is not aware that it has yet made its appearance in South Africa. 



" The young plant is first affected in the roots. After mid- 

 summer the disease manifests itself also in the full-grown corn 

 stalks, more particularly on the leaf-sheaths, by certain dis- 

 coloured areas. Even the developing ears are often infected, 

 showing a jelly-like disposition, occasionally becoming a mass 

 of rotten slime. An attack upon the very young plant means 

 the dwarfing of its growth and destruction of the crop. A 

 lessened yield and valueless fodder are the only results of infec- 

 tion of the more mature stalk. The presence of the disease is 

 noted to a greater extent some years than others. Means of 

 prevention have not yet been carefully studied, but destroying 

 affected parts is said to be the only sure way of absolute 

 eradication. This disease is sometimes known as ' corn 

 blight'" (Illinois Station Bull., 5). 



369. Stewarts Corn Wilt. — Another bacterial disease, in 

 this case caused by Pseudomonas Stewartii, has been reported 

 as destroying whole fields of maize in the United States. 

 Affected plants are said to wilt and dry up, but do not roll up 

 as when they suffer from lack of moisture. Young plants die 

 in a few days, but older plants may live for some time after the 

 first attack (Bowman and Crossley, 1). 



370. Yellow Foliage. — Yellowness of leaves points to an 

 unhealthy condition of the plant. It need not necessarily 

 indicate the presence of a parasitic disease, but is often caused 

 by a wet, cold soil, or the lack of sufficient sunshine, either 

 condition interfering with the proper nutrition of the plant. 



371. Chlorosis. — In Java the maize crop is said to be 

 particularly subject to Chlorosis, i.e. absence of chlorophyll, 

 which results in the development of white leaves. Cavers (1) 

 notes that chloritic culture plants are easily obtained with 

 maize, and that the condition is readily remedied by adding an 

 iron salt to the culture fluid. 



372. Physiological Effect of Drought. — Drought usually 



CHAP. 



x. 



