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CIRCULAR No. 365 OCTOBER 1935 



UNITED STATES DEPARTMENT OF AGRICULTURE 



WASHINGTON, D. C. 



*Ry 



THE CAMPHOR SCALE 



By A. W. Cbessman and H. K. Plank, associate entomologists, Bureau of 

 Entomology and Plant Quarantine 1 



CONTENTS 



Page 



Introduction 1 



Possible means of dissemination 3 



Host plants and injury 3 



Description of stages and habits 7 



Seasonal history 10 



Natural enemies 11 



Page 



Artificial control 11 



Oil emulsions 11 



Fumigation 17 



Summary 18 



Literature cited 19 



INTRODUCTION 



The camphor scale, (Aspidiotus) Pseudaonidia duplex (Ckll.), is 

 a serious pest of shade and fruit trees, which found its way to southern 

 Louisiana and other Gulf -coast localities about 20 years ago. Al- 

 though it attacks a large variety of plants, its most important hosts 

 are the camphor-tree, as its name indicates, and the Satsuma orange. 

 The insect is now established in the citrus-growing sections of south- 

 ern Louisiana, where it threatens to become an addition to the list of 

 major pests. 



Shortly after the discovery of the camphor scale in New Orleans in 

 1920, the insect was found in Alvin, Tex., in the vicinity of Mobile. 

 Ala., and in several places in Mississippi. Later, infestations were 

 found in Houston and Arcadia, Tex. The infestations in Mississippi 

 were thought to have been eradicated, but in 1932 the scale was dis- 

 covered at Logtown and Bay St. Louis. 2 Originally rather heavy 

 infestations occurred in the Satsuma orange district near Mobile, Ala., 

 but inspections in 1931 revealed only a few scales, and these were in 

 one Satsuma grove and on an abandoned plantation. 



There is evidence that Xew Orleans, La., Alvin, Tex., and Mobile, 

 Ala., represent three separate points of introduction from Japan, 

 for Japanese nurseries were located at Alvin and Mobile, and nursery 

 stock from Japan had also been imported into New Orleans. 



Although the finding of the camphor scale along the Gulf coast in 

 1920 apparently represented the first permanent establishment of the 

 insect in the TJnited States, it appears to have reached this country 

 in earlier years without gaining a permanent foothold. The first 



1 Most of the studies upon which the information contained in this circular is based 

 were conducted at the laboratory formerly maintained by the Division of Tropical, 

 Subtropical, and Ornamental Plant Insects at New Orleans, La. 



2 United States Department of Agriculture, Bureau of Entomology, camphor 

 scale (pseudaonidia duplex ckll.) U. S. Dept. Agr., Bur. Ent. Insect Pest Survey 

 12:20. 1932. [Mimeographed.] 



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