130 GARDEN AND FARM TOPICS. 



for rust, smut, or other mildew parasites, must, in my 

 opinion, be a preventive one; that is, whenever practi- 

 cable, use new land or renew the old land by a green 

 crop, such as Rye, Timothy, or Millet, in all sections 

 subject to these diseases. The same plan had better be 

 adopted in all sections where the Onion maggot, or other 

 insects, attacks the crop. 



The theory for this practice is, that it is believed that 

 nearly all plants affected by insects or disease have such 

 peculiar to themselves, and that the germs lie in the soil 

 ready to fasten on the same crop, if planted without in- 

 termission on the same ground, while if a season inter- 

 venes the larva or germ has nothing congenial to feed 

 on, and is, in consequence, destroyed. In practice, we 

 usually find that cultivated land " rested " for a season 

 by a grass crop gives always a cleaner and healthier crop 

 to whatever vegetable follows it. In cases, however, 

 where the land cannot be rested, or when it has been 

 rested to be cropped in spring, it is a great preventive 

 of the ravages of all kinds of insects to plow the land in 

 the fall as late as possible, so as to disturb the larvae of 

 insects and expose them to the action of frosts and rains. 



THE PRODUCT. 



The average product of the Onion crop varies very 

 much, ranging from 300 to 900 bushels per acre, the 

 mean being about 600 bushels per acre. The price is 

 variable like all perishable commodities, ranging from 

 fifty cents per bushel, the price at which they usually 

 wholesale in the New York market in fall, to $i or $1.50 

 per bushel for winter and spring prices. The estimate, 

 then, of profit per acre may be given about as follows; 



