INDUSTRIAL FUMIGATION AGAINST INSECTS 7 



grease or pasted with flour paste, and rolls of unsterilized adhesive 

 or masking tape, known as "fumigators' tape", all have their place. 

 Small doors leading to the exterior of the building can be tight- 

 ened by stripping around the edges with any of the materials used 



Figure 8. — Skylights and flashings on roof sealed in preparation for fumigation. All 

 ventilators must also be sealed. (Photograph furnished by W. D. Reed.) 



for the windows. Large sliding or hinged doors that fit imperfectly, 

 or elevator-shaft openings, can be sealed most effectively by forcing 

 a framework of 2- by 4-inch lumber covered with fiber-reinforced 

 waterproof paper against strips of heavy felt padding (figs. 10 and 

 11). Such a sealing can be used many times. Another method is 



Figure 9. — Windows sealed on the inside with paper. Cracks about unions of rafters 

 and walls are sealed with plastic cement. (Photograph furnished by W. D. Reed.) 



to calk the doors with a paste composed of 4 parts of asbestos fiber 

 to 1 part of calcium chloride mixed with a little water. The calcium 

 chloride will absorb enough moisture from the air to keep the paste 

 pliable and thus insure a tight seal. It is a cheap, yet effective, seal- 

 ing material and can be easily removed after the fumigation. 



