2 BULLETIX 707, U. S, DEPARTMEKT OF AGRICULTURE. 



BEDBUGS. 



METHODS OF TESTING. 



The tests of various materials, in many cases of previously unde- 

 termined insecticidal value, against the bedbug {Cimex lectularius 

 L.), are of two general types, (1) jar tests and (2) room tests. In the 

 former 20 bedbugs were confined in a pint jar with paper scraps or 

 excelsior to furnish hiding-places, and thoroughly dusted or sprayed 

 with the material to be tested, after which the jars were covered 

 with cheesecloth. At least two of these jars were used in each test. 

 Eecords were taken at the end of 24 hours, and as often thereafter 

 as was considered necessary. With each series of tests two similar 

 jars, each containing 20 bedbugs and paper scraps or excelsior, were 

 used as a check. If the mortality in these checks ran above 35 per 

 cent the whole series was discarded, except in those cases where the 

 mortalitA' in the treated jars was 10 per cent or less. No food was 

 furnished in anj' of these tests, but it should be noted that in many 

 cases the experiments were continued for two weeks with a mor- 

 tality of less than 10 per cent in the checks. 



This method of testing, although admittedly very severe on the 

 bugs, and not simulating natural conditions, was used primarily to 

 ascertain whether the given insecticide material would kill the in- 

 sects and was not intended to determine its exact value under prac- 

 tical conditions. 



Experiments on a practical scale were made by thoroughly dust- 

 ing badly infested rooms or beds with the material to be tested. In 

 these experiments the room or bed was examined only once, usually 

 four or seven days after treatment. 



KILLING EFFECTS OF LIQUIDS AGAINST BEDBUGS. 



HYDROCAKBON OILS. 



Twenty-seven different hydrocarbon-oil preparations, composed 

 largely of oils of the nature of kerosene and gasoline mixed with 

 varying amounts of nitrobenzene, phenols, essential oils, etc., were 

 tested. All of these were found to be very effective, most of them 

 killing 100 per cent of the treated insects within 24 hours. 



As remedies against bedbugs, the oil sprays possess one very great 

 advantage over other insecticides — their power of penetration. With 

 powders and most liquids it is very difficult, if not impossible, to 

 reach the bugs, which are generally hidden during the day in 

 cracks and holes in the beds, behind wall paper and moldings, or 

 in the bedding itself, and in these places they are readily reached by 

 the heavier oils. These sprays possess the added advantage of de- 



