Sirrine, F.A. 1901 Treatment for San José scale in orchards. I. Orchard fumigation.. Bulletin (New York Agricultural Experiment Station) No. 209: 344-371.

Notes: It is unsafe to leave trees in orchards exposed to action of hydrocyanic acid gas for periods of twelve hours. With perfect covers, debarring accidents, it is possible to kill every living specimen of pernicious scale on medium sized fruit trees without injury to the trees and thus to exterminate the pest in isolated sections. Tents are recommended.