GUAM AGRICULTUKAL EXPERIMENT STATION. 27 



vested is consumed on the island. Coffee was formerly more exten- 

 sively grown than at present and formed an article of export. Sugar 

 cane, rice, and tobacco ai'e not extensively grown, and the products are 

 used entirely in Guam. Forage crops are assuming more importance 

 in view of the large number of horses, mules, and other stock used 

 and maintained by the Government and the growing cattle industry. 

 Some of the island fruits are of excellent quality and bring good 

 l^rices in the market, but none are exported. They include the 

 mango, citrus fruits, breadfruit, bananas, avocado, soursop, and 

 pineapple. Recent introductions are strawberries, jDeaches, waterT 

 melons, smooth Cayenne pineapple, avocadoes, and improved pa- 

 payas. Vegetables of good quality are cultivated, including the 

 sweet potato, eggplant, beet, cucumber, radish, and cabbage. Other 

 plants of economic importance are cotton, rubber, broom corn, cas- 

 sava, peanut, kapok, bamboo, and numerous hedge trees, such as 

 the camachile {PUhecolohium dulce), ironwood {Casuarina equi- 

 setifolla) , Cassia grandifora., C. fistida^ etc. 



' A list of the principal economic plants with their insect depreda- 

 tors follows: 



SPECIAL FIELD CROPS. 



Coconut palm. The coconut palm is peculiarly free of insect pests 

 and fungus diseases, and the groves are all, as far as observed, in 

 thriving condition. Seedling plants are occasionally attacked and 

 destroyed by a borer, the widely distributed Rhabdocnemis ohscurus 

 (a variety close to the one from Christmas Island, described as R. 

 fausti, but merely a variant of the above-named species). A mealy 

 bug, Pseudococcus cocotis, is quite common on the trunk beneath the 

 leaf sheaths and does considerable damage. It is very much reduced 

 by a coccinellid beetle, jScymnvs sp. Slightly higher up on the trunk 

 and leaves a flat scale, Lepidosaphes sp., is commonly found. Hy- 

 menopterous parasites were bred from this scale and to some extent 

 check its multiplication. A phasmid or walking stick feeds on the 

 leaf, but does no appreciable damage, although the leaves are often 

 badly shattered, presumably from Avhipping and other mechanical 

 injuries. In such condition they harbor certain caterpillars which 

 are usually found in situations presenting dry dead vegetable matter. 

 The larva of a tineid moth is also commonly found on the leaves. 

 The pupa is parasitized by Chalr-is sp. No artificial remedies for 

 these insects are recommended. 



Corn. There are a large number of insects attacking corn. Seed 

 which was rotting was found to harbor earwigs, wireworms, and 

 other ground forms. Small plants are badly eaten by the cater- 

 pillar of a pyralid moth, Marasmia trapezalis. The caterpillar, 

 which is gi"een with broad and flat black tubercles, folds the leaves 



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