10 BULLETIN 566, U. S. DEPARTMENT OF AGRICULTURE. 



Dissolve the soap in a little of the water over a fire, then add the 

 rest of the water and the nicotine sulphate. This makes 1 gallon of 

 stock solution at an approximate cost of 50 cents. Use 1 part to 22 

 of water. 



Common laundry soap pound 1 



Water gallons 4 



Nicotine sulphate, 40 per cent teaspoonfuls 5 



The soap must be shaved fine and dissolved in about one-third of 

 the water, then the rest of the water and the nicotine sulphate are 

 added. This mixture is applied without further dilution and is 

 therefore practical only on a small scale. It does not give as good 



Fig. 8. — Flowerpot traps for earwigs. Shorter supporting 

 advantage. (Original.) 



stakes proved to be of 



results as that containing potash soap. Fish-oil soap also was tried 

 in this formula but burned foliage after several applications.* 



The foregoing two, being contact sprays, must actually hit the 

 insects and hit them well or death is not assured. For this reason 

 thorough spraying must be done at night, the insects being hit with 

 a fine mist as they crawl over the plants, vines, and grass. To sup- 

 plement this night spraying it is well to treat with a stream of the 

 same material any crevices where insects are plentiful through the 

 day. If necessary, the spraying of heavily infested areas should be 

 repeated at intervals of three nights until the results are satisfactory. 



TRAPPING. 



Trapping is the chief method of control recommended by Euro- 

 pean authorities. The best trap (fig. 8) appears to be a 3-inch 



