April, ’24] 
SASSCER & WEIGEL: GREENHOUSE FUMIGATION 
219 
gas may have an efficiency equivalent to the gas produced by the pot 
method, the manner of application has not reached the stage where it 
could be safely recommended to the average florist. The advisability of 
conducting this gas into a greenhouse by means of a force pump and 
then liberating it under pressure through a system of perforated pipes 
with adjustable nozzles permanently installed near the ridge of a house is 
now being made the subject of a special investigation. 
Plant Tolerance Experiments With Kentia and Areca Palms 
The regulations of the Louisiana State Department of Agriculture 
prescribe that nursery stock and plants originating within the camphor 
scale infested area and which are offered for sale interstate or intrastate 
must be hand inspected and fumigated with hydrocyanic-acid gas under 
supervision prior to shipment. In connection with this work the State 
inspectors frequently noted that Kentia palms in particular were severe!}’ 
burned when exposed to the gas at the hj ounce dosage sodium cyanide 
per 1,000 cubic feet of space. It seemed necessary, therefore, to conduct 
tests to determine the reason for the burning. The results of these 
experiments which were conducted at New Orleans by the junior author 
and W. D. Whitcomb during January and February 1923, demonstrated 
the following: 
All experiments show that Kentia belmoreana are burned to some 
degree if exposed for 1 hour to hydrocyanic-acid gas with a concentration 
of ounce sodium cyanide, or greater, per 1,000 cubic feet of space 
with humidity ranging from 50 to 80 per cent. 
Exposure to sunlight both before and after treatment tends to in¬ 
tensify the burning but the results were not all uniform. Fronds ex¬ 
posed directly to the light before and after were more severely burned. 
Wetting the plants prior to fumigation did not materially influence 
the results. 
No burning was observed on new spikes. There was no apparent 
difference in the tolerance of old and new fronds. 
Experiments with Areca lutescens indicate a much greater resistance to 
hydrocyanic-acid gas. However, some burning occurred under such 
unfavorable conditions as a humidity of 75 to 80 per cent and exposure to 
strong sunlight after treatment. 
It is evident from the results thus far obtained that Kentia palms 
cannot be fumigated with hydrocvanic-acid gas, even as low as 
