622 



Kalshoven (L.). Voorloopig onderzoek van een aantasting van 



levenden Djati door Xylehonis destruens, BldM. [A preliminary 

 Investigation of an Infestation of living Teak by A", destruens.] 

 — Reprint from Tectona, Buitenzorg, xiii, 1920, 26 pp., 2 figs., 

 2 plates. [Received 23rd October 1922.] 



The infestation of young teak trees b}^ Xyleborus destruens, Bldfd., 

 has increased the economic importance of this Scolj^tid in Java, where 

 prior to 1918 it was known only from diseased cacao. The infestation 

 is not readily detected in its early stages, as the bore-holes are incon- 

 spicuous and are sometimes covered by the shelters erected by termites. 

 It is indicated by the presence of dust, consisting chiefly of wood 

 debris, on the ground or bark. An attack of older date is revealed 

 by the brown semi-fluid material extruded from the holes and forming, 

 especially after rain, patches on the bark. Sometimes the holes are 

 distributed over the entire trunk up to the crown. After penetrating 

 some distance towards the centre of the trunk the mine divides into 

 two or more branches, which are not always on the same horizontal 

 plane. 



Further investigation is needed to elucidate the habits of X. des- 

 truens ; it seems to be a true ambrosia beetle, as the sides of the mines 

 are covered with a grey fungus. The female seems to oviposit at 

 intervals, so that the eggs, larvae, pupae and adults in a mine follow 

 each other. Among 116 individuals collected, only six (supposed) 

 males were found. Parthenogenetic reproduction seems to occur. 

 Nothing certain is known regarding natural enemies. 



When the infestation of teak was discovered, it was noticed that the 

 attack occurred in or near old wounds (some of which were due to 

 Duomitus ceramicus) or unhealthy parts, or seemed to have spread 

 from such points in otherwise normal trees. It has not yet been 

 proved, however, that the beetle has a definite preference for injured 

 or sickly parts of the tree. The injury does not appear to have any 

 unfavourable physiological effect on the teak trees, but the timber 

 may be so fufl of gafleries as to be fit only for fuel, and the consequent 

 financial loss may be very considerable. Remedial measures require 

 to be worked out, and in the meantime the fefling of infested trees 

 is advised. If a tree is slightly attacked near the ground, a liberal 

 application of tar may check the infestation. 



Kalshoven (L.). Zoologische Bijdragen. [Notes on Forest Zoology 

 for the Dutch East Indies.] — Tectona, Buitenzorg, xv, no. 8, 

 1922, pp. 677-693, 1 plate. (With a summary in English.) 



Since the creation in 1918 of a new department for forest protection 

 problems at the Forest Research Institute at Buitenzorg, the systematic 

 collection of data on injurious animals, especially insects, has been 

 carried out. Preliminary information, not suitable for bulletins, will 

 be published under the above heading. 



A twig-borer, Margaronia caesalis, Wlk., attacks Artocarpus integri- 

 folia in mixed forest plantations in Java. Repeated injury checks 

 the growth of the saplings. This Pyralid also occurs on saplings of 

 Artocarpus rigida and A. elastica. The young larvae were noticed 

 eating the unfolded leaves of the latter and niining in the main-rib. 

 Older larvae seem to bore in the pith of the shoots, making galleries 

 up to 5 in. long, where pupation takes place. In both 1920 and 1921 

 the borers occurred from January to March — the middle of the wet 



