74 



DISEASES OF CULTIVATED PLANTS 



should then be spread equally over the patch where it grew, 

 and a little dry straw or litter added, and fired. By this 

 means not only is the clover on the dodder destroyed, but 

 also the seeds that have fallen to the ground. 



A French scientist, M. Garrigou, recently announced that 

 if calcium sulphide is sprinkled over dodder, the latter blackens 



FlG. ii. Dodder (Cuscuta Gronovii), 

 parasitic on a species of Aster in Kew Gardens. 

 Nat. size. 



and withers within forty-eight hours, and during damp weather 

 is completely destroyed in that time. A series of experiments 

 conducted at Kew with two species of dodder proved that 

 neither calcium sulphide nor calcium sulphate (gypsum) had 

 any effect whatever on the dodder, although completely 

 covered with the substance and kept damp for a week. 



Dodder is introduced to land in the form of seed, mixed 



