242 Appendix. 



17. Hellebore. 



Powdered helebore, If fresh, is of value for poisoning insects wliicli are 

 injuring small fruits or vegetables which are nearly ready for market and on 

 which it is undesirable to use the arsenical poisons. It may be dusted over the 

 plants when they are moist with dew, or may be used as a spray in the fol- 

 lowing proportions : 



llelleboi-e 1 ounce 



Water 2 gallons 



18. Pyketiirum or Insect Powder. 



Fresh pyrethrum powder is a valuable remedy for flies, mosquitoes, roaches, 

 ants, fleas and other household pests. It is destructive to insects but not poi- 

 sonous to the higher animals or to man. It should be kept in an air tight 

 receptacle. The dry powder may be dusted over the floors, or in the hair of 

 dogs infested with fleas, or about their sleeping quarters ; or in other places 

 -where noxious insects congregate. It may also be used as a spray in conserva- 

 tories or on a few plants in the garden, in the following proportion : 



Pyretlirum 1 ounce 



Water 2 gallons 



It is also stated that the flies and mosquitoes in a room may be destroyed 

 by burning a little pyrethrum powder upon some live coals. 



19. Bisulphide of Carbon. 



Bisulphide of carbon is a colorless liquid with a very disagreeable odor. 

 It is very volatile and its fumes are poisonous to animal and plant life. 

 When mixed with air in the proper proportion they are also very explosive. 

 As an insecticide, it is valuable mainly as a remedy for subterranean insects, 

 borers, or insects infesting stored grains, seeds, etc, and for fumigating build- 

 ings which are infested with noxious insects. It is also used extensively for 

 destroying various burrowing animals whose burrows incline downward into 

 the earth. For this purpose pour two or three ounces of the liquid upon a ball 

 of rags, or other absorbant, place this well down into the burrow and close 

 the opening. Thus used it is an effective remedy for "digger squirrels" and 

 '•prairie dogs," but is not effective against moles and pocket gophers which con- 

 struct long, horizontal burrows. Troublesome ants' nests may be destroyed by 

 making a hole in the center of each nest and pouring into it two or three 

 ounces of the liquid, after which the hole should be tightly closed. For de- 

 stroying the root form of woolly-aphis of the apple, it is common to make 

 several holes each six to twelve inches deep about the tree and pour one or 

 two ounces of the liquid into each hole, which should be immediately closed. 



Borers in the roots of peach or prune trees may be destroyed by simply 

 pouring from one to three ounces of the liquid, according to the size of the 

 tree, about the base of the tree. If the soil is wet or compact, it is best, first, 

 to excavate a shallow trough about the tree and fill this with loose soil before 

 applying the chemical. 



For fumigating grains, seeds, storehouses and other buildings, including 

 houses, for the destruction of insects, one pint of the liquid is used for each ton 

 of grain or 1000 cubic feet of space. The building, bin or other receptacle 

 should be tightly closed and kept closed 24 to 36 hours. During this time no 

 person ishould attempt to enter the building, nor should any light he allowed 

 inside, until it has been thoroughly ventilated, since the fumes arc both poison- 

 ous and explosive. 



20. Hydrocyanic Acid Gas. 



This is an extremely poisonous gas which is used in this State principally 

 to fumigate nursery stock. In California it is used to fiunigate i citrus trees 



