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JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 13 
itself, and necessarily the program of control would have to be in 
accordance with the cultural methods, so as not to prove deleterious to 
the future growth of the plants. 
Ordinarily arsenicals are the standard remedies used to combat such 
ravenous leaf feeders. Hence, it was decided to make a few prelimi¬ 
nary tests of varying strengths of paris green, calcium arsenate, and 
arsenate of lead. It was found that powdered arsenate of lead did not 
injure the roses when used at the rate of two to two and a half pounds 
to fifty gallons of water, adding one-half ounce of soap to each gallon 
of spray material. All of the infested plants were, therefore, thor¬ 
oughly sprayed with the above insecticide, using a pressure sprayer. 
Special care was taken to cover all the foliage so that it presented a 
white-washed appearance which was retained for many days. Con¬ 
trary to the general reported control on strawberries with arsenicals, it 
was soon found, however, that under the existing conditions such meas¬ 
ures were ineffective. This was due to the particular choice which the 
adults showed for the young and tender growth that was being forced, 
during the hot sultry nights, and which in turn could not be sprayed 
constantly in order to keep it covered with arsenate of lead. This 
was coupled with the insects’ nocturnal feeding habit. Further, it was 
lound that they practically avoided the lead covered foliage. This 
naturally necessitated an immediate change of the control program 
because of the alarming rate at which the injury was proceeding. 
The next consideration, therefore, was the use of a standard fumigant 
such as hydrocyanic-acid gas which is frequently employed in green¬ 
house fumigation. Here again, we were confronted by the question 
of determining a killing dosage for the adult beetles, of which very 
little was known. Secondly, the advisability of using such measures 
on the tender growth. 
Preliminary experiments with a fourth to half an ounce of sodium 
cyanide per thousand cubic feet of space proved entirely ineffective. 
The maximum dosage which roses are known to withstand, using two 
ounces per thousand cubic feet of space was therefore employed. The 
exposure lasted two hours. It is advisable to point out the fact that 
fumigation at this strength and duration during hot sultry summer 
nights is contrary to the general recommendations for fumigating 
greenhouses, but drastic measures were imperative, otherwise the whole 
crop might just as well have been left to the insects for complete 
destruction which most certainly would have followed. 
An examination of the fumigated houses at 8:30 o’clock the following 
morning showed very encouraging results. The beetles were found 
lying on their backs, or sides, exposed on the surfaces of the foliage in 
great numbers. Many were killed in their tracks in the act of feeding, 
