519 



Tonkin, the tree known as "soan" and the "bancoulier" [Aleurites 

 moluccana (candle-nut)] do not seem at all attractive to the borer. A 

 coating of resin, oil and starch, mixed while hot, shouldgive good results. 

 It is inexpensive, and three months after application is still sufficiently 

 viscid to act as a repellent. 



In January the adult borers began to emerge from the experimental 

 branches and were examined. The teak branches were riddled with 

 emergence- holes, the adults appearing barely 3| months after oviposi- 

 tion. They were apparently a little smaller than the average size ; 

 this may have been due to crowding among the larvae. From freshly- 

 cut Gardenia used in the same experiments the adults were also a 

 little smaller than those emerging from cofiee. In AJbizzia, which 

 was suspected of being a favourite food-plant, no galleries have 

 appeared. Among newly tested living plants, Randia dumetorum 

 was attacked by X. quadrijpes, and produced two normal adults, 7|- 

 months after oviposition. This plant is largely grown, the fruit being 

 eaten by the natives. Another native tree, Oroxylon indicus, was 

 chosen for oviposition, sometimes in preference to cofiee, and galleries 

 were observed in the wood, but the experiments with this tree were 

 not completed. If these conditions are reproduced naturally in the 

 field, it is hoped that the branches of these plants may be utilised as 

 traps ; teak logs placed at the foot of cofiee bushes are already being 

 tested in this way. 



Washes and bands have not been very successful ; the former have 

 proved either inefiective or noxious to the trees, though possibly 

 in the case of quite old trunks a coating of bird-l ime might not be inj urious. 

 Bands are more expensive and only drive the beetles to oviposit above 

 them and on the branches, whence the larvae descend to the trunk. 

 The Hfe-cycle varies according to the severity of the winter, being 

 proportionately longer for those insects that hibernate as larvae in the 

 trunks. Examples are quoted that indicate a shorter larval stage on 

 newly-felled logs than on Uving plants. 



Other insect pests of cofiee plants include an unidentified white 

 scale that lives on the underground part of the plant and encourages 

 a disease that quickly spreads aU over the roots and causes the death 

 of the plant by sufiocation, in much the same way that Pseudococcus 

 (Dactylopius) vitis, Nied., infests vines in Palestine. The only remedy 

 as yet known is to pull up and burn immediately all plants so afiected. 



Rice pests in Tonkin include Schoenobius incertellus, Wlk., the 

 larvae and pupae of which pass the winter in rice stubble left in the 

 fields. The obvious remedy is to destroy the stubble, but it is doubtful 

 whether growers will do this. Parasites' of the larvae are numerous, 

 but do not prove an efiective check. Young rice plants are also 

 considerably injured by the caterpillars of another moth, Sesamia 

 inferens, Wlk., which mine the stalks and also live and pupate outside 

 at the base of the plants. As the rice-growers object to destroying 

 the infested stubble the damage is spreading. 



HuTSON (J. C). Some Minor Insect Pests in Ceylon in 1919. — Trop. 



Agriculturist, Peradeniya, liii, no. 2, August 1919, pp. 139-141. 



[Received 8th October 1919.] 

 The insect pests reported for the first half of 1919 include : Saissetia 

 hemisphaerica on twigs and leaves of tea, giving rise to the development 



