INSECTS INJURIOUS TO AGRICULTURE IN JAPAN 91 



Harmolita phyllostachites and Aiolomorphus rhopaloides. They 

 occur, however, upon species of no great commercial value. Accord- 

 ing to Ishii, the first named was probably introduced into Japan from 

 the United States. 



TERMITES IN WOOD PRODUCTS 



Aside from the damage produced hy termites upon growing trees, 

 there are, according to Oshima (155, 156), three species which seri- 

 ously attack cut timber, wooden buildings, etc. These are Copto- 

 termes formosanus, Leucotermes (Reticulitermes) flaviceps, and L. 

 speratus. The first occurs in Japan, China, and Taiwan, the second 

 in Taiwan only, and the third in Japan, Taiwan, and Chosen. Ex- 

 periments were conducted to determine the cause of the relative 

 immunity of various kinds of wood and to find a method of treating 

 those susceptible to protect them from attack. It was found that 

 teak (Tectonia grandis) and cypress pine (Calletris glawca) were 

 absolutely immune to injury owing to the presence of organic com- 

 pounds inimical to the termites. The principal constituent having 

 this quality was found to be sesquiterpene alcohol, and the same 

 protection was secured when other woods were treated with a prepa- 

 ration of this compound. Though teak wood is evidently the most 

 resistant of all tropical woods to termite attack, the growing trees 

 are not entirely immune, as is shown by the extensive damage done 

 to teak forests in Java by Calotermes tectonae Damm., which appar- 

 ently confines its attacks to this tree alone. 



MISCELLANEOUS FOREST INSECTS 



The cerambycid Melanauster chinensis, which is known largely 

 because of its injury to orange and mulberry trees, is a serious pest 

 of Cdsuarina stricta in the forests of Taiwan. According to Maki 

 and Rin (88) the eggs are laid from April to July in crevices in 

 the bark of the trunk. It has been determined that the larvae remain 

 from one to three weeks under the bark before boring into the wood, 

 and this habit has been utilized in devising control measures. The 

 location of a larva is detected by the presence of excrement at the 

 point of entrance, and a small section of bark is removed at this 

 point, thus exposing the larva. One man is able to examine and 

 treat 250 trees a day in this way. 



Seed-feeding chalcids are particularly numerous in some parts of 

 Japan, and counts made by Yano and Koyama (%08) from 1913-1916 

 gave the following percentages infested : 



Per cent 



Chamaecyparis obtusa 94 



Cryptomeria japonica 3. 6-13 



Larix leptolepes 2 



Thujopsis dolabrata 2 



On the basis of observations covering a period of years, Yano (207) 

 has come to the conclusion that infestations of forest insects are 

 much more severe in pure plantings than in mixed, this being attrib- 

 uted to the fact that the parasites have less chance of finding an 

 intermediate host upon which to perpetuate themselves during the 

 time when the primary host is at the lowest point numerically of its 

 cycle. In support of this conclusion he cites observations in 1917 



