THE FUNGUS PESTS 



OF 



GARDEN PLANTS 



r ^HE plants of our gardens and farms are very liable to attacks 

 from destructive fungi. Cures are in most instances un- 

 known, but preventives seem to be in many cases within reach. 

 When first-class seed is sown, and receives good cultivation, a strong 

 and robust growth will probably be the result. Well-grown and 

 healthy plants are known to be less liable to the attacks of fungus than 

 ill -grown and weakly ones. It is amongst the ill-tended and weakly 

 that disease generally begins, and from these centres of contamination 

 it too often spreads to well-cultivated places. It is therefore a matter 

 of the first importance in the prevention of disease that the best seeds 

 should be sown, and that they should be developed by good culti- 

 vation into robust and vigorous plants. 



POTATO DISEASE. Every cultivator of Potatoes must have noticed 

 the white flocculence which grows on the discoloured patches of 

 diseased Potato foliage. This white flocculence is the dreaded 

 Potato fungus or rather fungi, for there are two distinct species. 

 When the flocculence cannot be seen on the patches, the fungus 

 spawn is growing inside the leaf, and has not yet emerged in a floc- 

 culent form from the organs of transpiration of the foliage. 



That the two fungi are capable of causing the disease, is proved 

 by the following fact. When the fungus spores are taken from an in- 

 fected plant, and placed upon the leaves of a healthy one, they imme- 

 diately germinate, penetrate into the interior of the Potato leaf, and at 

 once reproduce the parent fungus and with it the Potato disease. 



The names of the Potato fungi are Peronospora infestans and Fusi- 

 sporium Solani. They are both microscopic in size, and require the 

 highest powers of the microscope for their proper examination. Both 



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