POPPY DISEASE DISEASES OF VIOLETS 



413 



A 



FUNGUS OF POPPY DISEASE 

 Peronospora arborescens 



P, somniferum and all its garden varieties. The fungus grows 

 within the leaves, and emerges with a tree-like growth through the 

 organs of transpiration on the under side of the leaves. Like the 

 fungus of the Potato disease, it speedily sets up decomposition, and 

 destroys the host plant. 



At A is illustrated one of the stems of the Poppy Peronospora 

 emerging from the leaf, engraved to the same scale as the Potato 

 Peronospora viz. enlarged 

 seventy-five diameters to show 

 the difference in size and habit. 

 The fungus of the Poppy is 

 very much more branched 

 than that of the Potato, and 

 every little branchlet carries a 

 spore. To save confusion, a 

 large number of spores are 

 omitted from the branchlet 

 in the illustration, and the 

 branches growing from the 

 stem both before and behind 

 are for the same reason left out. 



At B a tip of a single branch is shown further enlarged to four hundred 

 diameters, or to the same scale of enlargement as the spore D on the 

 Potato fungus illustration. The spores in the Poppy fungus are un- 

 usually large and numerous : an infected plant will throw off many 

 millions of such spores. All the putrefactive spawn of this fungus is 

 inside the host plant ; cure, therefore, is difficult. This disease, like 

 every other plant disease, is always at its worst in ill-kept places where 

 red field Poppies are abundant. Field Poppies are often planted with 

 unclean corn. As prevention is better than cure, all we can advise 

 is, buy the best and cleanest garden and field seeds, cultivate in the 

 best way, and look out for and burn, or deeply bury as soon as de- 

 tected, all disease-stricken plants whether wild or cultivated. When 

 diseased plants of any sort are left to decay on the refuse heap, it is 

 the most certain way of propagating a plant disease for the next year. 



DISEASES OF VIOLETS. Violets are subject to fungoid diseases, 

 both in spring and autumn. The disease of autumn is caused by a 

 brown Pucdnia allied to the P. graminis of corn and the P. malvace- 

 arum of Hollyhocks and various malvaceous plants. The Pucdnia of 

 Violets has its yellowish or orange-coloured stage ; it is then known 



