January, 1910.] 



85 



limbers. 



treated poles are given a special coating, 

 of some unknown antiseptic, which 

 extends about 2 ft. above and 2 ft. below 

 the point where the pole enters the soil. 

 This application protects the part where 

 variations in humidity commonly attack 



the pole, In the Himmelsbach establish- 

 ment there are tanks for impregnating 

 forty ties at a time, under pressure ; these 

 tanks being about 65 ft. long, and over 6 

 ft. in diameter. Their baths for treating 

 telegraph poles are 98 ft. in length. 



PLANT SANITATION. 



REVIEW. 



The " Mosquito-Blight " of Tea. (Helo- 

 peltis theivora.) Investigations during 

 the cold weather season of 1907-1908. 



"Mosquito-Blight." Report on Ex- 

 periments during Season 1908 at Rampore 

 and Koombergram Tea Estates. 



By 0. B. Antram, f,e.s„ 

 Entomologist to the Indian Tea Asso- 

 ciation. 



These two circulars, issued by the 

 Indian Tea Association, were published 

 in 1908 and 1909 respectively, and detail 

 the results of Mr. Antram's investi- 

 gations into and experiments upon the 

 treatment of this most important tea 

 pest. In his Preface to the first cir- 

 cular, the author states that he has 

 "purposely refrained from giving the 

 life-history of the Tea Mosquito in any 

 great detail, as many matters relating 

 to the insect have seen so thoroughly 

 gone into and thrashed out in the last 

 few years, that to do so now would be 

 to go over much old ground." He fur- 

 ther remarks that he has contented 

 himself " by touching only upon those 

 points that have been left undecided, 

 and by giving particulars of the latest 

 discoveries and observations made in 

 connection with the life-history and 

 habits of the insect during special in- 

 vestigations carried out in the past sea- 

 son, and in particular the cold-weather 

 of 1907-1908." 



Although our local Tea-bug (I use this 

 name in preference to the misleading 

 term Tea-mosquito) Helopeltis antonni, 

 is considered to be specifically distinct 

 from its Indian ally, the appearance and 

 habits of the two species, and their 

 effect upon the tea plant, are so similar, 

 that we— in Ceylon — may take advant- 

 age of Indian experience, with modifi- 

 cations necessitated by the difference 

 in cultural methods that obtain in this 

 country, on which account I propose 

 to quote at some length from Mr. 

 Antram's valuable and interesting obser- 

 vations. In fact, my remarks will be 

 more of the nature of a resume than 

 of a review. 

 5 



The author estimates the pecuniary 

 loss through the ravages of Helopeltis, 

 in the year 1907, at ten lakhs of rupees. 

 His observation that a low jat of China 

 hybrid suffers most from the blight, 

 accords with our own experience in 

 Ceylon, where the difference in the 

 severity of the attack upon different 

 varieties of tea is most marked. 



The first part of the earlier circular 

 is devoted to a study of the habits of 

 the insect during the cold weather 

 months, which — according to the author 

 — " have never been completely followed 

 out until this last winter of 1907-1908. 

 Previous pamphlets record observations 

 mostly made during the time when the 

 insect is most active, i.e., at the height 

 of the season, and hitherto very little 

 has been found out with regard to how 

 its life-cycle is affected by the cold 

 weather." 



Mr, Antram sets himself to solve 

 the following important questions, ap- 

 parently with complete success : — 



1. " What became of the insect in the 

 cold weather, and where did it hibernate 

 if definite hibernation takes place ? " 



2. " How far is the life cycle affected 

 by the cold weather ? " 



3. " How long do eggs take to hatch 

 out in the cold weather, and do they lie 

 dormant until shoots are developed on 

 the bushes ? " 



With regard to the first question, he 

 finds that there is no true hibernation, 

 but that the " insects in all stages, from 

 freshly hatched specimens to adults, 

 could be found in large numbers on all 

 blocks of differently pruned tea as well 

 as on the unpruned. It was even quite 

 easy to find specimens upon very hard 

 pruned tea upon which there was hardly 

 a vestige of leaf." 



The answer to the second question 

 may be quoted in full. " Eggs laid in 

 November, December and January, 

 owing to the low temperature at that 

 time prevailing, take two and three 

 times longer to hatch out than at the 

 height of the season. The same applies 

 to the larvae which are very much longer 

 in reaching maturity, or the winged 



