JOim OF AGRICCITIIAL RESEARCH 



Vol. XVI Washington, D, C, February io, 1919 No. 6 



INJURY TO CASUARINA TREES IN SOUTHERN FLORIDA 

 BY THE MANGROVE BORER 



By Thomas E. Snyder 



Specialist in Forest Entomology, Forest Insect Investigations, Bureau of Entomology, 

 United States Department 0/ Agriculture 



INTRODUCTION 



In southern Florida many thousand casuarina, or "Australian pine," 

 trees (Casuarina equiseiijolia Forster) have been and are being planted 

 for shade and ornament along roads and avenues, on reclaimed swamp 

 land, on golf courses, along the seashore, and as windbreaks for fruit 

 trees (PI. 18, A). The tree makes a rapid growth, is not affected by salt 

 spray from the ocean, and is utilized for the same purposes as eucalyptus 

 trees in California. It is indigenous to tropical Asia and Australasia 

 and, in addition to southern peninsular Florida and the Florida Keys, 

 it has been introduced throughout the West Indies and other tropical 

 regions of North and South America. 



Reports of serious injury to casuarina trees in Florida by a bark- and 

 wood-boring insect {Chrysohothris tranquebarica Gmelin) * led to special 

 investigations by the writer which resulted in the discovery that this 

 buprestid beetle was a common and destructive enemy of the red man- 

 grove {Rhizophora mangle Linnaeus), and that, therefore, the mangrove 

 was the source of the trouble affecting the casuarina trees. 



The fact that this beetle has so changed its normal habits as to attack 

 and breed in a plant so different botanically from its common host, to- 

 gether with the economic importance of this changed habit to property 

 owners who have made extensive plantings of the casuarina, has ren- 

 dered the subject of special scientific interest and practical importance. 



The first reports of insect injury to the casuarina came from Hobe 

 Sound and Miami Beach in April, 191 6. These and other localities in 

 southern Florida were visited by the writer in May, 1916, March and 

 April, 1917, and April and May, 1918, in order that a thorough investiga- 

 tion of the insect, the conditions relating to its attack, and the methods 

 of combating it might be made. 



• Determination by Mr. W. S. Fisher, Bureau of Entomology. 



Journal of Agricultural Research, Vol. XVI, No. 6 



Washington, D. C. Feb. lo, 1919 



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