Resin-Lime Mixture 121 



(2) Contact Sprays. These materials are applied for 

 the purpose of destroying those insects which get their 

 nourishment by inserting the beak into the plants and 

 sucking the sap, rather than by chewing the flesh of the 

 fruit or the leaves. Plant lice and scales belong to this 

 group of insects, and since they suck their food, they 

 cannot be reached by those poisons which are to be chewed 

 up and swallowed. These sprays are more or less caustic 

 and penetrating, and kill by coming in contact with the 

 bodies of the insects. 



(3) Suffocation Methods. It frequently happens that in 

 some places, such as greenhouses and hotbeds, destructive 

 insects get on plants which cannot be sprayed with either 

 contact or food poisons, and the insects must be disposed 

 of by some means that suffocate them by filling up their 

 breathing pores, or cause their death by irritation. Such 

 means as these are useful only in the greenhouse, and for 

 insects that may work in the soil, in seeds, or on fruits or 

 vegetables that are about ready for the market. Of chief 

 importance among these suffocating poisons are tobacco, 

 carbon bisulphide, pyrethrum and hydrocyanic acid gas. 



Insecticides 

 Resin-Lime Mixture 



Stock Solution. 

 Pulverized resin, 5 pounds. 

 Concentrated lye, 1 pound. 

 Fish oil, 1 pint. 

 Water, 5 gallons. 



Dissolve the 'resin and oil together in a kettle over a 

 warm fire, and when it has become well dissolved and 

 somewhat cooled off, add slowly the lye and stir hard. 

 To the mixture add about two gallons of water and boil 

 it hard for about an hour, or until the mixture will dissolve 

 in cold water. When it has reached this condition add 

 enough water to make five gallons, and use this as the 

 stock solution for use in the following: 



