FUMIGATION OF ORNAMENTAL GREENHOUSE 

 PLANTS WITH HYDROCYANIC-ACID GAS. 



CONTENTS. 



I 'age. 



Equipment necessary for fumigation 3 



Preparation of greenhouse for fumigation 4 



Method of computing the cubical contents of 



even and three-quarter span greenhouses ... 5 



Time for fumigation 5 



Chemicals required for fumigation 6 



Determining the amoimt of cyanid to be used 6 



Chemical formula to be employed 8 



Mi.xing the chemicals 8 



Number of generators to be employed 9 



rage. 



Exposures 



Ventilation after fumigation 9 



Effects of weather and other conditions on 



fumigation 9 



Advisability of a fumigation box 10 



How greenhouses become infested with in- 

 sects 10 



Cost of hydrocyanic-acid gas fumigation 11 



Precautions 11 



Guide to greenhouse fumigation 12 



HYDROCYA'NIC-ACID GAS, if intelligently employecl is one 

 of the cheapest and most efficient methods of controlling 

 thrips, aphids, white flies, and various scale insects on plants 

 grown under glass. This method of control, however, has not 

 been adopted generally because of the deadly poisonous nature of 

 the gas if inhaled, its disastrous effect on tender plants if improp- 

 erly used, and the prevailing impression that fumigation is a cumber- 

 some procedure requiring considerable skill on the part of the oper- 

 ator. It is true that much damage to the plants and injury to the 

 operator may result from the careless use of hydrocyanic-acid gas, 

 but it is an established fact also that this fumigant in competent 

 hands is a safe, practical, and economical means of controlling virtu- 

 ally all insect pests found in greenhouses. 



EQUIPMENT NECESSARY FOR FUMIGATION. 



GENERATORS. 



One-half-gallon or one-gallon glazed earthenware jars serve as satis- 

 factory generators, although it is preferable that the bottoms of the 

 jars be rounded mside, so that the cyanid will bo covered with the 

 acid and water, even with small doses, thus insuring the maximum 

 generation of the gas. 



CA.VT10-N.— Hydrocyanic-acid gas is colorless and is one of the most deadly poisonous 

 gases knoivn. It has an. odor much like that of peach pits. In case of accidental inhala- 

 tion of the gas, the person affected should he kept in the open air and required to walk to 

 increase respiration. 



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