



UNITED STATES DEPARTMENT OF AGRICULTURE 



DEPARTMENT BULLETIN No. 1225 



Washington, D,C. T '. April 30, 1924 



THE CAMPHOR THRIPS. 1 



By W. W. Yothers, Entomologist, and Arthur C. Mason, Assistant Entomologist, 

 Fruit Insect Investigations, 2 Bureau of Entomology . 



CONTENTS. 



Page. 



Introduction 1 



History and distribution 3 



Origin 4 



Comparison of bay thrips and camphor thrips 4 



Nature and extent of injury 5 



Description 6 



Life history and habits S 



Page. 



Seasonal history 18 



Host plants 18 



Natural enemies -.-. 21 



Control measures 21 



Summary 28 



Literature cited 29 



T JNTRODUCTION. 



Many years ago camphor trees, Cinnamomum camphora (L.) Nees 

 & Eberm., were introduced into Florida for ornamental uses. The 

 beauty and grace of the tree made it very popular for the beautifi- 

 cation of grounds, roadways, and borders of groves. The ease with 

 which this tree was propagated and the luxuriousness of its growth 

 (fig. 1) led to the belief that it could be grown in large acreages to 

 obtain a commercial supply of camphor. 



The first attempt to produce camphor gum under commercial 

 conditions was made at Satsuma, Fla., in 1903. The total investment 

 on this plantation amounted to nearly one million dollars and during 

 the period of the existence of the plantation (1903-1921), 1,800 

 acres were set to camphor trees. Another plantation, consisting of 

 2,200 acres of camphor trees, was located at Waller, Fla., midway 

 between Stark and Green Cove Springs, and represented an invest- 

 ment of over a million dollars. It was thought that by using machin- 

 ery on an extensive scale camphor gum could be produced as econom- 

 ically here as in the Oriental countries, where the cost of labor is low. 

 Practically all of the work of planting the trees, cultivating, harvesting 

 the branches for distillation, and producing the camphor gum itself 

 was done by mechanical means. 



1 Cryptothrips floridensis Watson; family Phloeothripidae, order Thysanoptera. 



2 The present investigations were begun by C. A. Weigel, of the Bureau of Entomology, assisted by 

 C. A. Bennett, who conducted a large part of the field work during the first year. PracticaUy all the 

 biological work was done at Orlando, Fla., by the junior writer, together with observations made at the cam- 

 phor farm at Satsuma, Fla. The control work was done mostly on the camphor plantation at Satsuma, 

 and in addition pruning and spraying experiments were carried on at Orlando. Similar life-history work 

 was carried on at Gainesville, Fla., by Prof. J. R. Watson, to whom credit is given for certain notes and 

 valuable assistance. The writers desire also to express their appreciation to C. W. Loveland, manager of 

 the camphor plantation at Satsuma throughout the period of the investigations, who extended to them 

 many courtesies as well as material aid during the progress of the work. 



69578°— 24 1 



