20 BULLETIN 513, U. S. DEPAETMENT OF AGEICULTUEE. 



In order that there may be no confusion on the part of the reader 

 as to the insects referred to in the tables by their common names, both 

 their common and scientific names are listed herewith : 



Greenhouse white fly Trialcurodes vaporariorum (Westw.). 



Citrus mealy bug .Pseudococcus citiH (Risso). 



Long-tailed mealy bug ]'f<cudococcus adonidum (L.). 



Palm or avocado mealy bag Pseudococcus nipae (Mask.). 



Greenhouse Orthezia Orthezia insignis (Dougl.), 



Florida red scale Chrysomplialus fictis (Ashm.) 



Long scale Coccus elongatus (Sign.). 



Soft brown scale Coccus hesperidtim (L.). 



Palm aphis CeratapMs latanae (Boisd.). 



Hemispherical scale Coccus hemispherica (Targ.). 



Florida fern caterpillar Eriopus floridensis (Guen.). 



Aspidistra scale Hemichionaspis aspidistrae (Sign.). 



Tessellated scale Eucalymnatus tessellatus (Sign.). 



Azalea Eriococcus Eriococcus azaleae (Horv.). 



Azalea lacewing Stephanitis azaleae. (Horv.). 



Greenhouse thrips Heliothrips haemorrhoidalis (Bouchg). 



Onion thrips Thrips tabaci (Lind.), 



Cottony scale Pnlvinaria sp. 



Thread scale Ischnaspis longirostris (Sign.). 



Avocado white fly Trialcurodes floridensis (Quaint.). 



Rose leafhopper Typhlocyba rosae (L.). 



Chaff scale ,Parlatoria proteus (Curt.). 



CONCLUSION. 



The results indicated in the foregoing pages are for the most 

 part based on the fumigation of commercial houses under commercial 

 conditions. The slight variations in the percentage of insects killed 

 and injury to plants may be accounted for by the tightness or lack 

 of tightness of different houses. It is ob^dous, therefore, that it is 

 not practicable to give specific directions as to the amount of cyanid 

 to be employed under all conditions. A knowledge of the pests to 

 be controlled and of the condition of the plants and tightness of the 

 house under consideration will render it possible to determine the 

 dosage to be used. 



In fumigating a house containing a large variety of plants, using 

 the correct dosage and under proper conditions, it happens occa- 

 sionally that some plants appear to have been injured. However, 

 this injury is not permanent, as the plants will show new vigorous 

 growth in a short time. Repeated tests have demonstrated thor- 

 oughly that the growth of many plants is stimulated by hydrocyanic- 

 acid gas. 



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