INSECTS AND HIRDS 



killing fungi) like Bordeaux Mixture or diluted lime- 

 sulphur wash. One spraying then serves two pur- 

 poses. For large fields there are "horse sprayers" 



that cover several rows at 



one time. 



Lead arsenate and Paris green are 

 both deadly poisons to larger animals 

 and to man, as well as to insects ; and 

 care must be exercised in putting away 

 these mixtures and in cleaning the 

 vessels used in mixing them. 



(6) External poisons. 

 Since sucking insects obtain 

 their food from the interior 

 of the plant, and do not eat 

 its tissues, they would not 

 be destroyed by an internal 

 poison unless it were dis- 

 solved in the sap. This 

 would injure the plant. 

 Therefore an external poison 

 is applied to such insects 

 as are attacking the plants. 

 Two common external insec- 

 ticides are the following: 



(1) Kerosene Emulsion 



Hard soap pound 



Hot water 2 gallons 



Kerosene 2 gallons 



INSECT WORK ON LEAVES. 



The soap is cut into thin slices and dissolved in hot 

 water ; and the kerosene is added while the solution is 

 still hot. On dormant trees, without foliage, this solution 

 is diluted with eight times its bulk of water; on foliage, 



