746 



THE MONTHLY BULLETIN. 



the cheiuical. Flooding may be used, but is uot as satisfactory as 

 the former method. 



In very small seedbeds and benches the soil may be changed; care 

 must, of course, be exercised in procuring soil that is free from the 

 nematode. Before replacing, the frames should be thoroughly washed 

 with a strong solution of formaldehyde or an application of hot, freshly 

 slacked quicklime. This will destroy all larvae and eggs that may be 

 attached to soft decaying wood or that may be found remaining in 

 the cracks. Old infested soil should be placed where it will do no 

 harm. The worm may be killed by excessive drought. Do not throw 

 on the ground, but place the removed soil upon boards or metal sheet- 

 ing, spreading it out rather thinly and allow it to become thoroughly 

 dried ; by so doing the chances of establishing the j)est in an uninf ested 

 area are greatly reduced. 



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Fig. 395. — The badly disorganized root system of the tomato, the result of celworm 



infestation. (Original.) 



Field Control - Perennial Crops Present. 



As has already been mentioned, control of the pest in the field 

 depends largely upon the kind of crops that are grown. Tender 

 growing rootlets and root hairs, which are the means through which 

 the plant takes food from the soil, are extremely sensitive. Chemicals 

 and control measures that arc^ powerful enough to destroy soil pests 

 are usually very harmful to the trees, especially if the plant is in a 

 growing state. This factor must always be taken into considei'ation 

 in experimentation with chemicals in the orchard. 



Various chemicals have been experimented "with in soil in which 

 perennial plants are growing, these including carbon bisulphide, potas- 



