Il6 THE FIRST BOOK OF FARMING 



stance, the geranium and the rubber plant. The 

 leaves are constantly turning yellow and dropping 

 off or drying up. This sometimes occurs from over- 

 watering or not sufficiently watering the soil in the 

 pot or box. If the watering is all right the trouble 

 may occur in this way: The air of the house is 

 quite dry, especially in winter. As a result trans- 

 piration from the leaf may be excessive. More 

 water is transpired than is necessary, consequently 

 more is pumped by the roots and with it more food 

 is sent to the leaf than it can take care of. As the 

 excess of water is transpired the excess of food is 

 left in the leaf. The tendency is to clog its pores 

 and therefore interfere with its work, and gradually 

 weaken and finally kill it. The remedy for this is 

 to spray the leaves frequently so as to keep the air 

 about them moist and so check transpiration. Keep- 

 ing a vessel of water near them helps also as this 

 tends to keep the air moist. Dust sometimes chokes 

 the leaves. Washing or spraying remedies this. 



Sometimes house plants, and out-door plants as 

 well, become covered with a small, green insect 

 called the plant louse or aphis. This insect has a 

 sharp beak like a mosquito and it sucks the juices 

 from the leaf and causes it to curl up, interfering 

 with its work and finally killing it. Frequent spray- 

 ing with water will tend to keep these away. A 

 surer remedy against them is to spray the plants 

 with weak tobacco water made by soaking tobacco 

 or snuff in water, or to fumigate them with tobacco 

 smoke. Sometimes the under side of the leaf be- 



