498 



Speyer (E. R.). Report of Entomologist in Chiarge of Investigations 

 into Shot-hole Borer of Tea. — Ceylon Adminisimtion Rejwrts for 

 1916, Part iv, Dept. Agric, 1st February 1917, pp. C 8-9. 

 [Received llth September 1917.] 



Tea-fields are being treated by experimental methods for combating 

 Xylehorus fornicatus. In some, all branches are to be cut of! which 

 do not put out new shoots in from two to four months after pruning ; 

 others are to have the infested bushes pruned at stated times after 

 the original pruning ; the results will not be apparent for 18 months 

 in the case of the first method and two years in the case of the second. 

 An examination of tea-prunings buried with basic slag and sulphate 

 of potash showed that two months after burying prunings to a depth 

 of 1\ ft. the beetles were still breeding underground and were evidently 

 finding their way to the surface. The system of burying prunings on 

 estates is therefore deprecated and the burning of the woody parts 

 recommended. The experiment of breaking branches attacked by the 

 borer and leaving them attached to the bushes proved that the exposure 

 of portions of the galleries does not hinder the development of the 

 beetle in other pai-ts not exposed. 



Experiments were begun in October 1915 with 12 washes, made of 

 various proportions of resin, soda, creosote, fish-oil and carbolic acid, 

 which were applied to plots of 15 newly pruned tea bushes. Four washes 

 were found to be too thin in composition to protect the wood from the 

 borer. The others formed a varnish which would definitely prevent 

 entry or emergence of the insects. Six of these washed of! too easily 

 with the monsoon rains. The remaining two were temporarily 

 satisfactory, but after four months the bushes thus treated had made 

 no growth ; the experiment was not therefore proceeded with. In 

 January 1917, these bushes were found to have recovered completely 

 and further experiments are now being made with washes which may 

 act as a protection to young buds. Ricinus communis (castor-oil plant) 

 was found to be useless as a trap for the borer ; for though it becomes 

 heavily infested, it does not thereby reduce infestation in the tea 

 bushes. 



The trunks of Grevillea were examined to determine what species 

 of Scolytid beetle attacked their surface after removal of the bark. 

 After 18 days, 31 beetles were extracted from the cut surfaces, 

 including 23 examples of Xylehorus semigranosus (?), 7 of X. semiopacus 

 and only 1 of X. fornicatus. 



Speyer (E. R,). Shot-hole Borer of Tea. — Trop. Agric, Peradeniya, 

 xlix, no. 1, July 1917, pp. 17-21, 1 fig. 



The distribution of Xylehorus fornicatus (shot-hole borer of tea) in 

 Ceylon has been effected rapidly by two definite factors, namely the 

 removal of infested tea plants or prunings from one estate to another 

 and the natural flight of the insect ^^dth or without the assistance of 

 wind. The presence of the castor-oil plant, Ricinus comtnunis, which 

 is the true host-plant [see this Review, Ser. A, v, p. 51], has also 

 encouraged its increase. The female constructs a branched gallery 

 [see this Revieiv, Ser. A, v, p. 282] and the life-cycle is passed within 

 the wood. In wet seasons the development of the broods is greatly 



