February, 1910,] 



119 



Timbers, 



recently, it was very common to 

 treat wood by injection under pressure 

 of chloride of zinc, diluted with water. 

 While this antiseptic is efficacious, it 

 loses its qualities and becomes hydros- 

 copic. To overcome these disadvan- 

 tages, creosote was added to the mix- 

 ture, and under the title of "mixed 

 impregnation" this system has been 

 adopted for the treatment of white wood 

 ties which are too cheap to warrant the 

 use of creosote alone. Hard wood ties, 

 on the other hand, are impregnated 

 with creosote alone, the general effect 

 of which is to close the pores, coagulate 

 the sap, and kill the micro-organisms 

 in the wood. The use of creosote alone 

 is quite unusual in the treatment of 

 telegraph and telephone poles, because 

 of the odour, tendency to melt and run 

 under the sun, and objection raised by 

 the men employed to deal with them. 

 It is common therefore to use bichlo- 

 ride of mercury (the French Govern- 



ment use sulphate of copper), the 

 efficacy of which has been known 

 since the middle ages, when it was 

 used to arrest decay and the action of 

 insects. At . the Himmelsbach plant, 

 near Freiburg, this is used in 66 per 

 cent, solution. The wood is plunged 

 into timber or cement receptacles, and 

 there remains from ten to fifteen days. 

 In this plant, moreover, treated poles 

 are given a special coating of some un- 

 known antisepetic, which extends about 

 two feet above, and two feet below the 

 point where the pole enters the soil. 

 This application protects the part 

 where the variations in humidity com- 

 monly attack the pole. In the Him- 

 melsbach establishment, there are tanks 

 for impregnating forty ties at a time, 

 under pressure ; these tanks being 

 about sixty-five feet long, and over 

 six feet in daimeter. Their baths for 

 treating telegraph poles are ninety- 

 eight feet in length, 



PLANT SANITATION. 



ENTOMOLOGICAL NOTES. 



By E. Ernest Green, 

 Government Entomologist. 



The following notes are extracted from 

 my Journal for the last three months 

 (October 15 to January 15), and may 

 serve as a record of the insect pests of 

 that period. 



Another occurrence of 'root gall-worm,' 

 on tea seedlings has been reported from 

 the Lindula district (where it was asso- 

 ciated with a similar infestation of 

 Albizzia seedlings). Though this Nema- 

 tode is fatal to young plants, it does 

 not appear to affect older and well- 

 established tea bushes, in which the 

 root system has attained a depth beyond 

 the reach of this pest. In the nursery 

 in question, a certain number of the 

 plants had made good growth and had 

 developed sound tapi oots. The question 

 arose as to whether it would be safe to 

 put out these healthier plants, or 

 whether it would be advisable to destroy 

 the whole nursery. Considering the 

 apparent immunity of older bushes, and 

 the fact that these healthier plants had 

 already formed deep roots, I think that 

 the latter might be safely utilized. 



' Green Bug' (Lecaniumviride) appears 

 to be establishing itself upon tea on 

 several estates in the Haputale district. 

 Until quite recently, this once notorious 

 pest of the coffee plant had shown no 



special partiality for tea ; but this new 

 departure will require attention. It can 

 never obtain such a hold upon the tea 

 bush as it did on the coffee, because it 

 can be more readily checked at the 

 periodic primings. The destruction of 

 pruniugs by fire, on all fields affected by 

 this pest, should be enforced. The 

 pruned bushes should then be sprayed 

 with Kerosene Emulsion or with a soap 

 solution. If the bug; should reappear at 

 a time when the bushes are not ready 

 for pruning, the spraying should be 

 repeated, but with soap solution alone. 



Two further outbreaks of the Noctuid 

 caterpillar (Caradrina reclusa) have 

 occurred upon tea, in the Pussellawa 

 and Kandy districts respectively. This 

 pest is of rare occurrence and lasts — 

 apparently — for a single generation only. 

 It is doubtless held in check by natural 

 enemies. 



The usual and ever-recurrent tea pests 

 have been reported from time to time. 

 The 'Red Slug' caterpillar (Heterusia 

 cingala) has been received from several 

 districts in the Central Province. ' Red 

 Borer ' (Zeuzera coffece) appears to be 

 independent of times and seasons. ' Tea- 

 Tortrix ' {Capua coffearia) has attracted 

 attention in theDikoyaand Pussellawa 

 districts. ' Shot-hole Borer ' has been 

 recorded, for the first time, from the 

 Maturata district. 



Helopeltis has been seriously injuring 

 the Cacao on the Experiment Station, 



