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JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



all. In an orchard at Mortlake this year, carrying out that particular 

 point, we had trees pruned and every dead branch cut out. That was the 

 order. I did not see that every one was, but practically every one. We 

 found a man could do twenty trees a day. You would pay that man 

 about 5,s. a day ; we will accept 5s. ; 5s. divided by 20 brings it to 

 how much a tree ? — Sd. Does it pay or does it not ? I leave you to 

 settle in your own minds : is it worth while spending Sd. on a tree when it 

 would keep down an epidemic ? Is it worth 3d. or not ? 



Mr. Power : Might I ask a question ? During the winter months is 

 there any chance of getting at the spore — the scab spore I mean ? If we 

 spray in the winter is the spore in existence, and can it be attacked by 

 Bordeaux mixture or anything else ? 



Mr. Massee : No ; I believe spores are not in existence, or at least 

 they are at a discount altogether. What you have is the fungus present 

 in the branch as it were — the roots of the fungus present in the dead 

 shoots. The fungus produces fruit just about the time when the young 

 shoots are developing, so that the only hope is in cutting off all diseased 

 portions. 



Afternoon Session, Colonel Long, M.P., in the Chair. 

 The Chairman called upon Mr. Theobald to read his paper on 



" Washes used as Insecticides and Acaricides." 



Mr. F. V. Theobald : I am afraid I am undertaking rather a 

 difficult matter in opening the discussion on the spraying of fruit trees in 

 connection with insect pests, for two reasons. The first, because I know 

 little of the chemistry of the subject. The second, because I am not a wild 

 enthusiast about the spraying of fruit trees. As you all know, there are 

 a very great number of washes used for the purpose of destroying insects. 

 Some of these washes act directly, some act indirectly, and from what I 

 have seen a very large number of them do not act at all, so that we have 

 to discriminate if we are going to wash our fruit trees as to what we shall 

 use. As a matter of fact, we know very little about the spraying of trees. 

 We have got to learn definite facts from growers as to what happens with 

 the different washes, and it is only by summarizing the facts that we shall 

 be able to get something really definite. Laboratory results are useful, 

 but it is not until they have been checked by growers in many different 

 parts, under varied circumstances, that their full value is attained. 



The subject of the washing of fruit trees seems to me in its founda- 

 tion to be very largely a chemical one, entailing entomological and 

 mycological supervision. For that reason I do not feel I am at all 

 competent to speak, and I must deal with the subject mainly from the 

 point of view of the insects which the washes destroy. As an instance of 

 the changes we may have to make the following is interesting. We have 

 all been brought up to understand that there are two classes of washes, 

 those for destroying biting insects and those that kill such sucking insects 

 as the aphis and the Psylla by contact. We have been told that one can 

 only be used for one particular purpose, the other for the other. Mr. 

 Pickering tells us now, and I may say I partly agree with him, that it is 



