DISINFECTING NURSERY STOCK 



575 



busily working at the fragrant liver. The insects carried pieces of the liver 

 to their nests, and besides causing the death of those that had been destroying 

 my fruit, the next generation of yellow jackets was also destroyed, and so 

 complete was the destruction that there were not enough of the little pests in 

 that neighborhood the following year to require a repetition of the treatment. 

 There is no risk in so using the poison, for the yellow jackets will not return 

 to the fruit, and bees will not go near the meat. 



DISINFECTING NURSERY STOCK 



Cuttings, scions, young trees and vines, etc., can be freed from 

 insects by inclosing in a tight box or cask and placing a saucerful of 

 carbon bisulphide on the top of them, covering it with canvas or any 

 tight-fitting cover. The bisulphide vapor will destroy all insect 

 life in forty minutes. 



Disinfecting such materials on a larger scale may be done in 

 this way : 



Use square canvas sheets, sixteen to twenty feet in diameter, made of the 

 best ducking, double stitched and then painted with boiled linseed oil to 

 make it gas proof. The canvas must be perfectly dry before it is rolled up, or it 

 is liable to be destroyed by spontaneous combustion. To fumigate evergreen 

 stock use one ounce of cyanide of potassium (in lumps, not pulverized), one 

 fluid ounce of commercial sulphuric acid, and two fluid ounces of water to 

 one hundred cubic feet of enclosed space. For deciduous and hardy trees, when 

 dormant, use one-fourth more of each of the above. When the canvas has 

 been placed over the stock to be fumigated, prepafe the charge. Take a three or 

 four-gallon glazed earthenware jar, into which pour the ncessary quantity of 

 water, then the sulphuric acid, and place it well under-the canvas, the edges of 

 which are secured with soil or in some way so as to prevent the gas escaping, with 

 the exception of the edge immediately in front of the jar. The proper amount 

 of cyanide of potassium is then dropped into the jar from a long scoop, and 

 the tent is immediately closed, and remains so for one hour. 



It is hoped that this chapter will convey useful hints in the war- 

 fare against insects. Whenever questions arise which are not met 

 thereby, appeal should be made to the University Experiment 

 Station at Berkeley. A condensed statement of useful insecticides 

 is issued by the Station, prepared by Professor H. J. Quayle, as 

 follows : 



INSECTICIDES 



1. Lime Sulphur: 



Quicklime, 33 pounds; Sulphur, 66 pounds; Water, 200 gallons. 



Sift sulphur through box with screen bottom into boiling tank with 50 

 gallons of water. Add the lime and boil 45 minutes to one hour. Stir fre- 

 quently. Strain through cheese cloth or burlap and dilute to make 200 gallons. 

 If extra lime is desired strain in milk of lime when spray is ready for use. 



2. Commercial Lime Sulphur: 



The standard strength corresponding to the above formula is obtained 

 when commercial solution is diluted I to 9. 



Either of the above for San Jose and other armored scales to be applied 

 during dormant season, preferably in early winter or early spring. For Peacli 

 Moth as the buds are expanding in the spring. 



