CONFERENCE ON SPRAYING OF FRUIT TREES. 



327 



not necessary to use arsenical sprays ; that we can use emulsions, such 

 as we use for the destruction of aphis and Psylla, for killing caterpillars. 

 Whether the results that have been obtained in killing certain cater- 

 pillars will apply to all caterpillars we do, not know at present. This is 

 for experimenters to find out ; but if they do, what then ? It means that 

 we could use one wash which woulcj. destroy caterpillars and aphis at one 

 time, so I think we must acknowledge we have as yet only touched the 

 fringe of this subject ; therefore I would like to impress upon you very 

 strongly that those who go in for the spraying of fruit trees should do so 

 with a large amount of caution. They must not believe, because they 

 see it in a particular advertisement, that a particular wash is going to 

 destroy this, that, and the other insect. Try for yourselves and see what 

 a particular wash will do, and if it will not do what is claimed, try some- 

 thing else, but do not throw huge sums of money away, as I am sure 

 growers do, before they know what the wash which they are using is worth. 



We see that emulsions may destroy some caterpillars, so that further 

 experiment may show that we need to use only, one wash. But we have 

 got to consider from all points whether it is worth while to use the one 

 wash to destroy the aphis and the caterpillar, saving of course time and 

 money. I am sure that any form of mineral oil will do a certain amount 

 of damage to trees. Now, in the case of certain arsenical washes little or 

 no damage is done, so that one advantage must be weighed against 

 another to see which of the washes it is best to use. 



One thing I might suggest to growers is this : not to be led away 

 by glowing accounts of certain preparations. I am not going to say that 

 there are not patent washes which are good, but that there are others 

 which claim to do impossible things. As Mr. Spencer Pickering has 

 said, the more you see washes boomed, the less you find of value in them. 



Still, one other point before I refer to certain of these washes. I may 

 be wrong ; if so, you must contradict me. But I cannot help thinking 

 that growers are spending too much in washing or spraying, for two 

 reasons. First, they do not know quite what the washes are going to do ; 

 secondly, because I have frequently seen in different parts of England 

 people spending sums of money in washing their trees when there is 

 absolutely nothing the matter with them. Surely, if a person is quite 

 well he does not want to go to the doctor ; it is waste of money. Go to 

 the doctor if you are ill, but not if you are perfectly well. Spraying 

 is a costly process, and it should be cut down as low as possible, and 

 the trees treated with sprays only when there is something definitely the 

 matter with them. People say you do it for prevention. I venture to 

 challenge that ; there is no wash which we have at the present time which 

 is a preventive. As far as insects are concerned, washes are remedial. 

 You can destroy the insects, or you may be able to destroy the insects, but 

 as a preventive with two possible exceptions we have no substance which 

 will keep insects off. There is a possibility that quassia, for one, will 

 ward off the attack of aphis pro tern. It is also possible that nicotine 

 will ward off the advent of aphis and certain winged insects ; but beyond 

 that there is nothing we can do to prevent the insect from taking up its 

 abode and starting an attack on the trees, and neither of these two 

 vegetable washes has any lasting effect. 



