FIELD STUDIES OF THE DISEASE. 61 



would be advisable to carr}'^ it out. As a matter of fact it would pay 

 a planter, planning to cut down any great number of trees, to girdle 

 each tree at 1 to lA- meters from the ground so as to allow the trunk 

 to dry out. Then when it is felled it can be made into very serviceable 

 timber for use on the plantation. It is worthless for use in any con- 

 stantly moist situation, but is very valuable for siding or beams in 

 sheds and makes especially beautiful pillars. 



Besides destroying all sources of infection, it is desirable to reduce 

 to a minimum the number of insects visiting the tree. It has not yet 

 been proved that insects are a means of infection, yet their great 

 abundance in diseased trees leads one to think that they may play an 

 important part in distributing the germs. It is very rare not to find 

 some insects present in an affected crown. The ones most commonly 

 found are the earwigs ^ (Pyragra huscki Caud. and Anisolabis janei- 

 rensis Dohrn), occurring in the damp, rotted, and fungus-infected 

 part of the central leaves some distance above the heart. These same 

 species or closely allied ones have been found by the writer in the 

 diseased trees in Cuba, Jamaica, Trinidad, and British Guiana. There 

 have been a few cases, however, when these forms could not be found, 

 so that they can not be given the entire blame. A few cockroaches ^ 

 (LeucopJiaea surinamensis L., Blahera fusca Brunn., and Periplaneta 

 australasiae Fab.), are very commonly present in and about damp, 

 decaying portions. Ants may often be found in great numbers, even 

 forming a nest in the crown. A few beetles," such as Lioderma quad- 

 ridentatum Fab., Cydonotum jiavicorne Muls., Ischyrus flavitarsis Lac, 

 and Lioderma devium Muls. ; and weevils ^ (RJiynchopTiorus palmarum 

 L.) occur, but seldom in abundance. In the midst of the moist, rot- 

 ten parts of the tissues centipedes, tree frogs, lizards, small snakes, 

 and rats may very frequently be found. Although it has not been 

 proved that insects carry the disease, it would seem advisable in a 

 seriously infected district to place about the trees, a meter from the 

 ground, bands of cloth 10 centimeters wide, soaked in coal tar, which 

 wiU prevent the ascent of the tree by any forms of crawling insects. 

 When it is known that rats or any of the larger animals frequent the 

 tops of the trees of any grove it would pay to put a band of galvan- 

 ized iron about the tree, some 15 centimeters wide and about H meters 

 from the ground. Themannerof destroying insects already in the crown 

 of the tree and any flying insects that may come to it is more difficult. 

 In the hope of reducing the number to a minimum the writer undertook 

 to spray a small grove during the course of a year. The experimental 

 work was carried on at a grove about 3 kilometers from Baracoa, 

 which could be reached only by traveling over an extremely rough 



* Identified by Mr. A. N. Caudell, of the Bureau of Entomology. 

 2 Identified by Mr E. A. Schwarz, of the Bureau of Entomology. 

 228 



