104 MARYLAXD AGRICULTURAL EXPERIMENT STATION". 



it is doubtful whether any of them will prove of more benefit than the 

 kerosene emulsion just mentioned. Owing to the fact that we have had 

 no summer experience with this insect in the East, we can not state posi- 

 tively the strengths of certain washes which may be nsed successfully with- 

 out damage to the trees during the summer. In California, however, one 

 of our agents, Mr. I). W. Coquillett, has nsed with success, during the 

 summer, a resin wash which was made in the following proportions: 



Resin pounds 20 



Caustic soda (70 per cent, strengtli) do 5 



Fish oil pints 3 



Water sufficient to make gallons 100 



It is probable that this mixture will not be too strong for eastern 

 trees, since, in general, with other insecticides, the climate of California 

 seems to render trees rather more susceptible to injury than is the case 

 in the East. For a winter wash the same ingredients may be used in the 

 following proportions : 



Resin pounds 30 



Caustic .soda (70 per cent, strengtii) do 9 



Fish oil pints 4)4 



Water sufticient to make gallons 100 



The most favored winter remedy in California, however, is the lime, 

 salt, and suli)hur mixture. This is generally used throughout the State 

 by progressive fruit growers. It consists of: 



Unslaked lime pounds. ...10 



Sulphur pounds.... 5 



Stock salt pounds.... 4 



Water to make gallons.. .15 



This wash will do great damage to the trees if applied during the 

 gv owing s,eii&o\\, and s/iou id be used oniy in winter. All the sulphur and 

 half the lime are placed in a kettle, and 8] gallons water added, after 

 which the contents of the kettle are boiled briskly for about an hour. The 

 solution, which at first is yellow from the sulphur, will turn very dark 

 brown, assuming more or less of a reddish tint, and will finally change 

 from a thick batter to a thoroughly liquid condition, the product being 

 ordinary sul])bide of lime. All the sulphur is added to the remaining five 

 pounds of lime and the latter slaked, after which the slaked lime and salt 

 are added to the sulphide of lime already obtained, the whole being then 

 diluted with water to make fifteen gallons. This should be strained before 

 application, as it does not form a perfect liquid solution, on account of the 

 considerable (Quantity of undissolved lime, which will soon settle to the 

 bottom, unless the solution is constantly stirred while being sprayed. 



In the experience of the Division in California and Washington, 

 this solution has not been as successful as could be desired, but it has 

 considerable popularity among the fruit-growers of California. 



The Gas Ti-eatment . — This method has not been extensively used 

 in California against this insect, but has been used Avith very consider- 



