PLANT DISEASES DUE TO FUNGI. 49 



In all probability the fungus found on the cucumber " is only an 

 intermediate condition of some higher form of fungus." As yet the 

 life-history is not fully known. 



Much can be done to avert the disease by a proper system of 

 cultivation. Over-watering undoubtedly predisposes the plants to 

 disease. 



Spraying with a weak solution of sulphide of potassium immedi- 

 ately the disease makes its appearance will hold it in check. All 

 diseased leaves and badly attacked plants should be burned. 



GLADIOLUS SMUT. 



Urocystis gladoli, Smith. 



In July last specimens of Gladiolus were received from Guernsey 

 very badly attacked by this Smut. 



The fungus usually makes its appearance as a series of spots on 

 the leaves, later forming masses of spores within the corms. The 

 spore masses contain an outer layer of sterile spores and an inner mass 

 capable of germination. They become washed into the soil by the 

 action of the rain and the soil thus becomes the chief source of infec- 

 tion. It is of course possible that these spore masses may adhere to 

 the surfaces of the corms and in this manner disseminate the fungus. 



Since infected soil is the chief source of trouble, it would be well, 

 wherever the disease has occurred, to give a dressing of i cwt. of 

 flowers of sulphur and 15 cwt. of ground unslaked lime to the soil, at 

 the rate of 15 cwt. of the mixture per acre. The soil so treated 

 should not be used for six or eight weeks. 



The corms to be planted should be first soaked in a solution of 

 formaldehyde, consisting of i pint of the former to 15 gallons of water. 



Good results have been obtained in treating an allied species 

 (U. cepulae, Frost) that attacks onions, by soaking the soil with a 

 solution of i Ib. of formaldehyde in 30 gallons of water. 1 



Corms seriously attacked should be burnt, as also diseased plants 

 when removed from the soil. 



As this disease is very common in Germany and France, imported 

 corms should be avoided. 



1 Thaxter, R. Rpt. Agric. Exp. Stat. Conn., 1889, pp. 129-153, pis. 1, 2. 



