THE ONION 



8l 



Economic Entomology: "Keep a close watch for the first 

 signs of maggots, and lift out and destroy infested plants 

 that have wilted down. Turn away the earth from the rows 

 with a hand plow so as to expose the root system in part, 

 then broadcast about 600 pounds of kainit and 100 pounds 

 nitrate of soda per acre; turn back the earth to the plants. 

 The application is best made just before or during, or imme- 

 diately after, a rain * Bisulphide of carbon injected 

 below the root system has been used with success." (On 

 small areas only, I presume. An injector or large syringe 

 or a machine-oil can may be used for the purpose. J. B. ) 

 "It should be used when the soil is moist but not water- 

 soaked * * * Tobacco dust, soot, wood ashes, etc., applied 

 early around the base of the plants * * Carbolic acid 

 emulsion pour\ed about the base of infested plants." (See 

 Chapter V for formula.) Fall-plowing is a help, too par- 

 ticularly if you will scatter a little grain on the field occa- 

 sionally afterwards and then turn on a flock of chickens. 

 Smut is held in check to some extent by rotation of crops, 

 by transplanting, and by gathering and burning infected 

 specimens and refuse. A mixture of equal parts of sulphur 

 and lime sown in the drills with the seed has given good 

 results as a remedy for the disease. Or the seed might be 

 treated with formalin as advised for cabbage in Chapter XI. 

 Cutworms are sometimes troublesome in the onion field (see 

 Chapter XI for remedies). Thrips (tiny, yellow insects that 

 suck the juices from the leaves) may be killed by spraying 

 with whale-oil soap solution or kerosene emulsion. Downy 

 mildew sometimes affects onion tops on low ground. Reme- 

 dies: Destroy diseased onions and spray plants early in the 

 season with the Bordeaux mixture which spray would also 

 be a help to keep smut in check. 



AN INSECT DESTROYER 



