10 BULLETIN 1079, U. S. DEPARTMENT OF AGRICULTURE. 



Carbolic soap solution: One pint crude carbolic acid added to one gallon soft 

 soap, thinned by addition of one gallon of hot water, left to stand overnight, and 

 then diluted with eight gallons of soft water (recommended in literature). — 

 Pine and ash, sprayed and dipped June 1, were attacked by all types after 

 10 days. 



, Five per cent solution of nicotine sulphate. — Pine, liickory, ash, and juniper 

 were sprayed, and all were attacked by type 4 within 10 days. 



Two teaspoonfuls nicotine sulphate dissolved in three ounces of alcohol and 

 added to one and one-half gallons water. — Pine and ash, sprayed and dipped^ 

 were infested by all types after 15 days. 



Ten per cent solution of sodium carbonate. — Pine and hickory logs sprayed 

 were immediately attacked by all types possible. 



Five per cent solution of a proprietary crude cresol-soap disinfectant.— 'Pxa.Q^ 

 juniper, ash, and hickory were sprayed but were all attacked by all types 

 possible. 



A strong suspension of whitewash. — Pine logs dipped were heavily attacked 

 after the first rain. 



A strong solution of sodium chlorid. — Pine logs sprayed were immediately 

 attacked and their condition was no better than that of the controls. 



One part crude pyridin preparation, to ten parts water. — This did not mix 

 well. Pine and ash were dipped June 1. After 30 days both woods were 

 infested by all types possible, but were in somewhat better condition than 

 the controls. 



One part crude pyridin preparation to ten parts kerosene. — ^Pine and ash 

 were dipped June 1. After 60 days no insects had attacked either wood. 

 The odor could still be detected on the logs. This material seems to be very- 

 promising and deserves further trials. 



REMARKS ON POISONS USED. 



Several of the more active poisons seem to be effective against 

 certain types of insects, particularly those of type 1. They are 

 especially effective when combined with oils that will penetrate the 

 bark (as the mixture of corrosive sublimate and kerosene) or fol- 

 lowed by another solution rendering them insoluble (as arsenic acid 

 followed by lime water). This latter, however, is difficult to apply. 

 They are also more effective when used on absorbent types of bark 

 as ash and juniper. 



OTHER EXPERIMENTS WITH INSECTS OF TYPE 3. 



The results of the preceding treatments were not conclusive against 

 the ambrosia beetles (type 3) for two reasons: These insects require 

 wood that is moist — at least such wood presents optimum condi- 

 tions — in which to rear their broods. The logs used in the preced- 

 ing experiments, averaging only 6 to 10 inches in diameter, often 

 dried so rapidly that they were not suitable for these beetles. At the 

 same time another series of experiments was being conducted in 

 which water-soaked logs were used. These acted as traps, attract- 

 ing most of the ambrosia beetles. 



