Nov. 4, 1918 



Fumigation of Cattleya Orchids 



267 



Table III. — Results of experiments similar to those given in Table I, except that all 

 plants fumigated were previously ftimigated in New York City on May 27, igi^, with 

 I ounce of sodium cyanid per 100 cubic feet, with an exposure of 40 minutes tinder par- 

 tial vacuum as described in the text 



Treatment before, during, and after 

 fumigation. 



Number, sec- 

 ond fumiga- 

 tion, July 30, 

 1917, of — 



Number, November 

 22, 1917, of — 



Leaves. 



Pseud o 

 bulbs. 



2 3 





Wrapped 2 hours before fumigation 

 and kept wrapped 24 hours 



Same as above, except wet 



Same as above, except dry 



Same as above, except wet 



Wet, held in dark 2 hours prior tof umi- 

 gation ; not wrapped when fumigated . 



Control 



Hr 



iK 



46 



46 



3S 

 54 



47 



i8J4 

 17^4 



a Three in poor condition. 



6 Five black. 



<• In box. 



All plants used in the experiments recorded in the tables were selected 

 at random, effort being made in so far as possible to equalize the number 

 of leaves and pseudobulbs in each test. Moreover, it was discovered 

 after the plants bloomed that four species of Cattleya were represented — 

 viz, trianae, mossiae, schroederae, and percivaliana. Unfamiliarity with 

 these plants rendered it impossible for the writers to separate the different 

 species by the characters of the pseudobulbs and leaves. So far as the 

 different varieties were concerned, however, there was no noticeable dif- 

 ference in the final results. Of 116 plants fumigated, only 8, or approxi- 

 mately 7 per cent, died. 



As indicated in the tables, the plants were fumigated under unfavor- 

 able conditions as regards temperature and moisture. This was deemed 

 advisable, since orchids are offered for entry in large numbers during the 

 summer months, and at this season it is frequently impossible to work 

 with low temperatures; and, furthermore, these plants occasionally are 

 drenched with water en route. 



All plants listed in Table III received two fumigations, the first ex- 

 posure being in New York on May 27, with sodium cyanid at the rate of i 

 ounce per 100 cubic feet of space, with an exposure of 40 minutes and a 

 preliminary 20-inch vacuum. 



All plants used were grown by Dr. James S. Cannon, the orchid expert 

 of the propagating gardens of the War Department, and in many cases 

 were not potted for weeks after fumigation. It is evident, therefore, 

 that the cattleyas were not given special treatment, but were handled as 

 a commercial shipment. 



