154 GARDENING FOE THE SOUTH. 



out fine filaments and rapidly grow into a mature fungus. 

 There are two kinds of these spores, or, rather, two con- 

 ditions. One stage belongs to the summer period, and is 

 to be found on the surface of the host, while the other 

 belongs to the winter, and is deeply seated in the tissues 

 of the plant upon which the fungus was developed. The 

 fruit and leaves are common places for the latter stage 

 of the fungus. 



From the fact that the fungus soon tinds its way into 

 the tissues of the host plant it will be readily understood 

 that the application of remedies to the surface will have 

 but little, if any, effect in destroying the disease. We 

 must, therefore, greatly rely upon preventive rather than 

 curative methods. 



There are many species of fungi attacking the culti- 

 vated plants, and the vigorous investigations of the 

 Experiment Station workers all over the United States 

 are bringing to light new forms each year, but the limited 

 character of this book will permit the mention of only a 

 few of the most destructive and troublesome species. 



Bacillus amylovorus (Burrill). Fire blight, frozen sap 

 blight, pear blight. This serious destruction of the pear 

 tree is the result of the attack of a minute bacterium 

 which causes the fermentation of the sap and the loaves 

 to turn a dark brown, and even the wood is made to crack 

 under the freezing and thawing of tissues in their un- 

 healthy condition. By this cracking of the wood the 

 bacteria are often given access to the older portions 

 of the tree. The first attack made by the bacteria is 

 through the nectaries and stigmas of the flowers, in the 

 soft tissues of the twigs and leaves where a wound has 

 been made. When a diseased tree is permitted to stand 

 the germs are transmitted by insects to the healthy trees, 

 as they fly from one flower to another seeking for the 

 nectar. When placed in this favorable condition the 



