484 



CITRUS FRUITS AND THEIR CULTURE. 



Treatment. Experiments have shown that this 

 trouble may be controlled by the use of Bordeaux mix- 

 ture in very weak solution, one to twelve and one-half 

 or fifteen used as a preventive, not as a curative. The 

 dangerous period to the fruit is while it is still young. 

 It would be best to commence spraying during the dor- 

 mant period, before the trees bloom, and spray once a 

 month until the fruit is well formed, that is, about the 

 month of July. 



Lichens. These plants 

 are found growing upon 

 stones, logs, boards, fences 

 and living trees through- 

 out the country. In color 

 they are yellow, green, red- 

 dish or gray. Their forms 

 are many and varied; 

 some adhere closely to the 

 substances on which they 

 grow (crustaceans) ; some 

 are branched and elevated 

 (fruticose) ; while others 

 present a rough, crumpled 

 surface ( foliaceous ) . 

 From the botanist's stand- 

 point, lichens are among 

 the most interesting mem- 

 bers of the vegetable king- 

 dom; they consist of a 

 fungus and an alga grow- 

 ing together, each contrib- 

 uting to the welfare of the other (symbiosis) . The fungus 

 furnishes water containing food in solution and shades 



Fig. 105. Lichens on trunk of an 

 orange tree. 



