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JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



use either the caustic alkali wash, or a distinct improvement on the old 

 c austic alkali wash, Mr. Pickering's Woburn wash, which is caustic soda 

 combined with paraffin and soft soap. 



The only difference between the old caustic soda wash and the Woburn 

 wash is that the addition of the paraffin in the latter makes it work very 

 much quicker, and is thus slightly better probably than the old caustic 

 wash, working underneath the covering that protects the eggs of the 

 mussel scale and rapidly destroying them. If you use the Woburn wash, 

 or caustic wash, for the destruction of the eggs, we will say of the apple 

 sucker, it will have no effect. Neither has it any effect even when used 

 at double the usual strength. It is not because you do not hit 

 all parts of the trees. It is because we have not anything sufficiently 

 powerful at present to burn through the shell and reach the embryo 

 inside. What I would suggest in the case of apple sucker is to leave the 

 winter spraying as late as you possibly can, and not aim at destroying the 

 egg, but aim at preventing the little apple sucker from making its exit 

 from the egg-shell. This I have seen done in several cases with such 

 good results that I am quite convinced that it is the best treatment. 

 It is merely spraying the trees with lime and salt. You should get the 

 lime on as thick as you can — whether salt is necessary or not is still 

 in dispute. I think it is necessary. By spraying the trees with this 

 lime and salt you form a covering over the egg-shell. The eggs of 

 the little apple sucker are laid mostly in two places just where the 

 lime and salt collect, and if you watch them you will find that the eggs 

 hatch, but a very small per cent, of the young crawl away. You will 

 never stamp out these creatures, but a very large proportion of them are 

 unable to make their way through the particles of lime alive. They die 

 long before they get into the apple buds and do the damage, so that 

 if you have a bad attack of apple sucker you should winter-spray, not 

 with paraffin, Woburn wash, or caustic wash, but with the lime-salt wash. 

 The eggs are not killed ; the insects are merely checked from escaping 

 whilst in their delicate condition from out of the egg-shell, and so from 

 getting into the buds. If you want to wash your pear trees that are 

 attacked with the disease that has been spreading rapidly during last 

 year, the pear-leaf blister mite, you should use winter wash again. The 

 trees should be washed with the lime, sulphur, salt, and caustic soda 

 wash, the so-called self-boiling wash (see p. 351). This wash has been 

 found in America to destroy the young mite that produces this disease, 

 and I have tried it myself on several trees with complete success. 

 You will not only have cleansed your trees of this mite, but I believe 

 I am right in saying that this wash has also a certain amount of 

 fungicidal action, and in it you have a remedy against a pest which 

 Woburn wash or lime and salt would have little effect upon. In winter 

 washing fruit trees, therefore, you may have to decide what you want to 

 destroy beyond the mere fact of keeping the tree in a clean and healthy 

 condition, which is absolutely necessary. 



I will now briefly refer to the arsenical washes. It may be that we 

 shall be able to discard arsenical washes, but until we know more, and 

 have found by experiments and have the opinion of a very much larger 

 number of '/rowers that the ordinary emulsion will destroy caterpillars, 



