502 ANNUAL REPORT SMITHSONIAN INSTITUTION, 19 64 



The dark, southern subterranean termite Reticulitermes virginicus 

 (Banks), whose northern range was Washington, D.C., in 1951 was 

 found at Philadelphia, Pa., and has been found on Long Island, N.Y., 

 since 1959. The light southern subterranean Reticulitermes hageni 

 Banks, whose northern range was Washington, D.C., was found in 

 1958 in a building at Trenton, N.J. It is believed that these last two 

 northward spreads were due to the trend toward warmer winters. 



Most States have only the subterranean types as injurious species 

 of economic importance but California and Florida both have all three 

 types. 



The California Structural Pest Control Board at Los Angeles issues 

 quarterly pest infestation reports by counties, giving the comparative 

 amount of damage for the three types of termites. Averaged for 55 

 counties out of 58 for 1962 and 1963, the figures are : Dampwood 0.4 

 percent, drywood 33.8 percent, and subterranean 44.52 percent. The 

 remaining percentage related to other matters. 



For the entire United States, it is estimated that the losses caused 

 amount to one quarter billion dollars. 



CONTROL 



PREVENTION 



With the increase in the number of buildings constructed on concrete 

 slabs on the ground and consequent increase in the number of buildings 

 infested with subterranean termites, the less costly pretreatment of 

 the soil with insecticides became practicable in the late 1950's. Before 

 the concrete slab is laid, you must secure proper drainage, remove all 

 wood debris from the building site, and saturate the soil with long- 

 lasting soil poisons such as water emulsions of chlordane and dieldrin. 

 This may save more difficult and expensive treatment after the house 

 has been built. 



FUMIGATION 



The most successful method of killing drywood termites damaging 

 buildings in southern California and southern Florida is to seal them 

 with heavy Kraft paper or cover them with tarpaulins and then fumi- 

 gate with heavy dosages of lethal gases. Of course there is no residual 

 effect and the buildings may soon become reinfested. However, it 

 would take a long time to build up new destructive populations. 



DESICCATION 



Dr. Margaret S. Collins, now of Howard University, Washing- 

 ton, D.C., has since 1950 been interested in differences in toleration of 

 drying between species of our native subterranean termites {Reticu- 



