92 GARDENING DIFFICULTIES SOLVED 



removed when growing strongly and gradually introduced to the full 

 daylight to bring them to their proper colour. 



Marguerites Suddenly Withering 



Q. I am sending you two Marguerites which have suddenly 

 withered and died. I should like to know the reason why, as I 

 have lost a good few in this way. Other Marguerites in the same 

 beds and window boxes are looking very healthy. Last year I lost 

 some in the same way, plants very much larger than those I am 

 sending you, in fact, one measured over 1 yard in diameter. I 

 should esteem it a favour if you can tell the cause and how to 

 remedy it, as I am afraid my beds will soon begin to look unsightly. 

 Marguerite, Sussex. 



A. The plants are infested by the Sclerotium disease, a parasitic 

 fungus which probably attacks and kills more plants of different 

 species, and belonging to widely separated orders, than any other. 

 The disease first shows itself in the sudden cessation of growth in 

 the plants. Upon examination the roots and rootstem are found to 

 be dead, and on them, usually at or near the ground line, appears a 

 very delicate white mould encircling the stem. The mycelium also 

 penetrates into the interior, and gradually extends upwards. Finally 

 the stem becomes dry and brittle and falls down. The whitish fluffy 

 mould first seen soon changes to a brownish colour, and liberates 

 clouds of minute spores when rubbed. This is the earliest and most 

 frequent form under which the fungus appears, and is called the 

 Botrytis or summer stage. In Potatoes, Beans, and other plants 

 with hollow stems, the mycelium or spawn grows up inside the 

 stem, and there forms numerous irregularly shaped solid bodies 

 varying in shape from that of a Mustard seed to that of a grain of 

 wheat. In the Chrysanthemum and other plants of a semi-ligneous 

 nature, these bodies are formed just beneath the bark, anil somewhat 

 more sparsely and much smaller. They are at first white or pale in 

 colour, but become black outside when mature, and are called 

 sclerotia, and give name to the fungus, viz. Sclerotinia sclerotiorum. 

 They remain in this condition until the following season, when, 

 owing to the decay of the host plant previously, and thus liberated, 

 they produce spores which infest a new crop. The prevalence of 

 the sclerotium disease is due to plants containing sclerotia being 

 left on the land, or in the dead plants being thrown on the rubbish 

 heap, and their remains as vegetable mould being returned to the 

 land. It is important, therefore, to remove and burn all plants 



