24 FUMIGATION METHODS 



be reduced to o. 10 to o. 15 gramme cyanide. As a rule, 

 it is not desirable to fumigate such plants as cedars, 

 pines, etc. 



Seeds of various kinds can be fumigated in nor- 

 mal amounts of gas with perfect safety, the varying 

 physiological effects depending upon the condition of 

 the grain or seed, whether dry or moist, upon the 

 amount of gas used, the length of time exposed, and 

 the atmosphere in which it is confined, whether dry, 

 damp, or saturated. This is treated more fully later 

 in another chapter. 



Low-growing plants may be fumigated for the de- 

 struction of the root aphis, leaf-rollers, and other 

 insects, but the work must be done with the same care 

 as for other plants. Lettuce, cucumber, and canta- 

 loups are very easily injured if the plants are damp, 

 even with small amounts of gas. In tests made by Pro- 

 fessor K. D. Sanderson, of the Delaware Agricultural 

 Experiment Station, upon young cantaloups after a 

 shower, he found the plants were injured in 0.40 

 gramme of cyanide per cubic foot for ten minutes. Pre- 

 liminary tests should be made with o. 10 to 0.20 gramme 

 for ten to twenty minutes before an entire house is ex- 

 posed. Professor Sanderson has shown also that straw- 

 berry plants freshly dug and fumigated in a box will 

 withstand o. 20 gramme cyanide fifteen minutes. His 

 tests show that this strength will kill the aphids on the 

 roots and not injure the plants. Other details are given 

 in a later chapter on this topic. 



