TOBACCO MILDEW 81 



TOBACCO MILDEW 

 (Peronospora hyoscyami, De Bary.) 



In Europe this fungus is not uncommon on the leaves 

 of Henbane (Hyoscyamus niger). Farlow has recorded that 

 it is parasitic on Nicotiana glanca in California, whereas it 

 occurs as a destructive parasite on cultivated tobacco in 

 Queensland, from whence specimens were sent to Kew for 

 determination as far back as 1887. 



PREVENTIVE MEANS. Spraying with dilute Bordeaux 

 mixture has been found effective in checking the spread 

 of the pest. 



MAIZE MILDEW 



(Peronospora maydis, Racib.) 



In Java the maize or Indian corn crop suffers severely 

 from the attacks of a Peronospora. Young plants are 

 attacked ; as a rule the first two or three leaves are 

 healthy, later ones becoming whitish or very pale green, 

 and soon afterwards the plants droop and die. 



The conidia emerge through the stomata. The disease 

 appears in twelve to eighteen days after infecting a leaf 

 with conidia. 



It is supposed that the disease has passed from some 

 native grass to the maize. 



PREVENTIVE MEANS. No experiments are recorded. 

 Oospores present in the soil are considered as the principal 

 factors in infection. 



Care should be exercised to prevent the disease from 

 F 



