and Magazine of the Ceylon Agricultural Society. —October, 1912, 



325 



across an instance in which the copper sulphate 

 was being dissolved in an iron cauldron : if that 

 is done the mixture contains no copper at all 

 and is quite worthless. 



The Question of Speayeks 



is a difficult one. In a case like this, where it is 

 desired to put as little copper as possible on 

 the tree, sprayers must be used : if the mixture 

 is applied with a brush too much is put on. 

 Moreover, it takes a long time to paint a tree, 

 whereas the stem can be sprayed in less than 

 a minute. The type of sprayer generally used 

 in temperate climates consists of a tank filled 

 with the liquid which is pumped out as re- 

 quired ; the operator carries the sprayer on his 

 back, pumps with one hand and directs the 

 jet with the other. This is undoubtedly the 

 best type; but it has always been stated in 

 Ceylon that a cooly will not work with both 

 hands. The Four Oaks sprayer is of that type ; 

 and as it has been strongly recommended in 

 Southern India,it seems probable that that cooly 

 difficulty has been exaggerated. Another type 

 of sprayer is filled under pressure, and the cooly 

 has only to direct the jet. But the sprayer 

 of that kind used in Ceylon is not a success. 

 As the liquid is under pressure, the slightest 

 defect in the fittings of the jet results in ex- 

 cessive waste, and as much fails pn the ground 

 as is put on the tree. There is no means of 

 agitating the liquid in the tank, consequently 

 the copper compound settles and cakes at the 

 bottom ; and as the pressure falls, it fails to 

 drive out a large proportion of the liquid. But 

 the most serious objection is that more than 

 half the cooly's time is taken up with the pro- 

 cess of refilling. With the ordinary sprayer the 

 liquid is simply poured into the tank, an 

 operation which takes less than a minute; but 

 the pressure sprayer requires anything up to a 

 quarter of an hour. There is another type of 

 pressure sprayer in which the liquid is poured 

 in, and the pressure obtained by pumping ifci air, 

 that is less objectionable, but with regard to 

 waste it is as unsatisfactory as the other. What- 

 ever sprayer is adopted, it should be capable of 

 being taken to pieces, especially the pump part 

 of it. Personally I consider that the best appara- 

 tus is a Deeming pump fitted on a small barrel. 

 That requires two coolies, but a greater quantity 

 of the mixture can be taken, and less time is 

 wasted in refilling. The jet should be of the Ver- 

 morel type. The straight jets used in cacao 

 spraying were made under a complete misappre- 

 hension of what was required in spraying oper- 

 ations, 



Collecting Spouts Should be Removed 

 before trees in tapping are sprayed ; if they 

 are not, the latex collected immediately after- 

 wards will be far more likely to contain copper 

 compounds. (Laughter.) Finally, I may once 

 more urge the necessity of training two or 

 three coolies to detect canker, and to treat it 

 when it first appears. It is not a disease to be 

 alarmed about, provided that it is treated in 

 the early stages. I am confident that on the 

 majority of estates, a sanitary gang would quite 

 repay its cost. The cooly proved quite efficient 

 in detecting and treating cacao canker, and 

 there is no doubt he would be equally capable 

 of dealing with the same disease on Hevea. It 

 was suggested, eight years ago, that the mycolo- 

 gist should inspect every rubber estate once a 

 year. That, of course, is physically impossible, 

 if the inspection is to be of any value. More- 

 over, it is not the work of a mycologist, A 

 mycologist has to investigate a disease, discover 

 the cause, and prescribe remedies; and when he 

 had finished one, there are always others 

 awaiting attention. If his time is taken up 

 with the inspection of known diseases, investi- 

 gation ceases. To a great extent, the two duties 

 are incompatible, and in any branch the inves- 

 tigator can only inspect for the purpose of 

 extending or completing his investigations : he 

 inspects to obtain knowledge. What estates 

 want is not a mycologist so much as an inspector 

 who is fully acquainted with all the known 

 diseases and can advise as to treatment. When 

 the inspector discovered any disease which was 

 new to him, he would bring it to the notice of 

 the mycologist for investigation. (Loud ap- 

 plause.) 



The Chairman : — lam sure we are very pleased 

 for Mr Petch's remarks. Things have been put 

 in a very interesting manner, and will be of very 

 great value in enabling us to detect any canker 

 or disease that we see on our rubber trees, and 

 when detected will enable us to check its growth. 

 This lecture will be reported in the papers fully, 

 and so we shall be able to see it all there and 

 be able to keep it end refer to it in the future. 

 It will be of very great value to us. I should 

 like to propose a most hearty vote of thanks to 

 Mr Petch for having come here today and given 

 us this most interesting lecture. (Hear, hoar, 

 and applause). 



Mr Petch— bowed his thanks, and later on 

 delivered impromptu talks to an assembled few 

 on the " Pink " disease. 



