THE TREE DOCTOR 233 



insects (plant lice, etc.), use one part emulsion to fifteen or 

 twenty parts water. 



Kerosene emulsion kills by contact, and therefore the appli- 

 cation should be very thorough. It may be used against a great 

 many different pests, but is especially valuable for destroying 

 those with sucking mouth-parts, for they cannot be killed with 

 arsenical poisons. 



Caution Only the dilute emulsion, 1 part emulsion to 15 or 

 20 of water, should be used when the trees are in leaf, and in all 

 cases it should be kept thoroughly stirred ; otherwise the foliage 

 or even the twigs will be injured. 



12 Paris Green. 



In combination with Bordeaux mixture, Paris Green may 

 be used at the rate of one pound to 175 to 200 gallons. 



When Bordeaux mixture is unnecessary, the Paris Green 

 may be used at the same rate, but two or three pounds of freshly 

 slaked lime must be added to prevent burning of foliage. Keep 

 the mixture well stirred so that the poison will be distributed 

 evenly. 



In cases where successive sprayings are necessary it is im- 

 portant to consider the accumulation of the poison and use a 

 slightly weaker mixture, unless sufficient rain has fallen to wash 

 off the poison thoroughly. 



13 Arsenate of Lead. 



Arsenate of soda, 4 ounces. 



Acetate of lead, 11 ounces. 



Water, 16 gallons. 



Dissolve each separately in two quarts of warm water ; mix 

 and add water to make sixteen gallons. Arsenate of lead can 

 be purchased from Swift Bros. Insecticide Co., Boston, Mass., 

 or under the name of Disparene from Bowker Insecticide Co., 

 Cincinnati, Ohio. It should be used at the rate of three pounds 

 to fifty gallons of water. It is perhaps the best of the arsenical 

 poisons in adhering qualities. This material may be used alone 

 or in Bordeaux mixture. 



