46 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
only a short while before the flooring, paneling, and uprights are 
attacked. 
Termite-Resistant Woods 
A few tropical woods are more resistant to termite attack than any 
grown in this country. The untreated heartwood of a few species 
of native woods has been found fairly resistant to termites under 
most conditions. These native species are close-grained heartwood of 
redwood, tidewater red bald-cypress, certain species of juniper, and 
the dense heartwood of longleaf pine, which contains a high percentage 
of resin. 
Wood Preservatives 
When wood must be used in direct contact with the ground, it should 
be thoroughly impregnated by a standard pressure process with coal- 
tar creosote or some equivalent preservative. Whenever possible, tim- 
ber should be cut to proper dimensions before treatment, but when 
cutting after treatment is unavoidable, the cut surface should be 
thor oughly treated with two or three brush coats of the hot preserva- 
tive. For further discussion see pages 41-44. 
Owing to the ramifications of the termite galleries in a building 
which has been infested for some little time and the protection which 
they have in their burrows concealed in the wood, control by fumiga- 
tion, by spraying. or by injecting chemicals into the infested wood has 
not proved satisfactory. 
Soil Poisons 
Protection over a period of several years may be obtained by apply- 
ing chemicals to the soil adjacent to the foundations of buildings. 
(See pp. 483-44.) Ina building having a full basement these chemicals 
should be thoroughly worked deep into the soil. 
A good method of obtaining a thorough distribution of the chemical 
along a foundation wall is to dig a trench and replace the soil gradu- 
ally, using alternate layers of soiland chemical. Where it is not possi- 
ble to dig: a trench, protection may be cbtained in light soils by digging 
post holes or punching holes with a bar about 12 inches apart. These 
holes, like the trench, should be deep where there is a full basement. 
Where 10-percent of sodium arsenite, orthodichlorobenzene, tri- 
chlorobenzene, or a 5-percent solution of pentachlorophenol is used, 1— 
114 gallons per linear foot should be applied. Where creosote and 
petroleum oil is used, the proportion should be 1 to 2 parts, respec- 
tively. Such treatment is most effective when combined with necessary 
structural repairs or alterations. Chemical treatments alone are not 
recommended as a permanent cure. Caution must be exercised in 
using these soil poisons, as they may kill shrubbery if they come 
in contact with the roots. Soil poisons may contaminate wells. 
Frequent Inspections 
Termite damage frequently can be prevented by careful inspection 
of the premises twice a year. in order to detect the first evidences of 
damage. Merely breaking down any earthlike shelter tubes and re- 
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