JOMALOFAGRianillALlSEARCH 



Vol.. XV Washington, D. C, November 4, 1918 No. 5 



FUMIGATION OF CATTLEYA ORCHIDS WITH HYDRO- 

 CYANIC-ACID GAS 



By E. R. Sasscer, Chief Inspector, and H. F. Dietz, Entomological Inspector, Federal 

 Horticultural Board, United States Department of Agriculture 



INTRODUCTION 



As a preliminary, it will not be out of place to refer briefly to the regu- 

 lations of the Federal Horticultural Board governing the importation of 

 orchids prior to the adoption of fumigation with hydrocyanic -acid gas as 

 a requirement for entry. These plants, which for the most part originate 

 in countries that do not maintain a recognized inspection service, were 

 allowed to enter under permit through designated ports of entry which 

 were provided with Federal inspectors, or collaborators of the Federal 

 Horticultural Board. Orchids arriving in the ports designated were ex- 

 amined by representatives of the board, and, if found to be free from 

 insects and diseases believed to be injurious, were liberated from customs 

 and allowed to proceed to the consignee. 



INSECT PESTS INTERCEPTED 



A total of 137 species of insects were collected on imported orchids, 

 principally species of Cattleya, or in cases containing them, from August, 

 1912, to December 16, 1917, including 41 species of scale insects and a 

 number of recently introduced ants which are now finnly established and 

 responsible for considerable injury in greenhouses as far west as Indiana. 

 A careful examination of three cases of Colombian orchids by the junior 

 author revealed the presence of 1 7 species of insects distributed in the fol- 

 lowing orders : Orthoptera, Hymenoptera, Hemiptera, Coleoptera, Lepi- 

 doptera, Corrodentia, and CoUembola. 



Early in the spring of 1917 a shipment of 47 cases of cattleyas from 

 Colombia was found, upon examination by Messrs. H. B. Shaw and D. G. 

 Tower, of the Federal Horticultural Board, to be infested with larvae of 

 an unrecognized pyralid moth not known to occur in the United States. 

 Inasmuch as these larvae were present in numbers on and among the roots 

 of the plants, the writers were instructed by the Federal Horticultural 

 Board to conduct experiments immediately to determine the possibility 

 of killing these larvae and other insects by the vacuum process without 

 removing the plants from the original container. 



Journal of Agricultural Research, Vol. XV, No. $ 



CTV Washington, D. C. Nov. 4, 1918 



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