Mr Dunn, Dalkeith Gardens, who for three years fought a most determined and successful battle at Powerscourt, in Ireland, with this Vine-destroyer, has kindly furnished us with some particulars regarding it, which were not at first intended for publication, but which he has permitted us to lay before our readers; and we do not know of any one who has had more experience in watching and dealing with this insect, nor any whose observations could be more reliable. Mr Dunn writes: - ".I am very glad to hear that you have decided upon burning all your infected Vines and removing all the borders, and at the same time thoroughly cleansing every part of the houses, making sure that not a vestige of the insidious pest is left. By doing so you will have much more confidence that you have thoroughly stamped it out. Had I to deal with it again I would certainly deal with it in the same way, unless I had very special reasons for cleaning and saving the Vines, though I hope I may never have the task of dealing with it again. One attack from so dreadful a scourge is quite enough in a lifetime.

By taking proper means, I have not the slightest doubt but that the very worst infected vineries can be effectually cleansed; for with all my three years' experience of it, I never found that the insect lived more than 48 hours when isolated from the Vine. Indeed, in all the numerous experiments I tried in placing it on other plants than the Vine tribe, it never lived 48 hours; but on the Vine it prospered and increased with amazing rapidity. I tried it on American varieties, such as Concord, Isabella, Sombruska, and the result was the same. There were Camellias, Azaleas, Cacti, Palms, Fuchsias, Pelargoniums, etc, with various sorts of bedding-plants in the vineries, and although -their foliage in some cases was put amongst the infected Vine-leaves and their roots, in other cases running through their pots into the border amongst the infected Vine-roots, I never found an insect feeding on any plant except the Vine, and only in a very few instances did I find them trespassing on any other plant; and when I did find them, I usually took them to my office and placed them carefully under glasses, where I could watch them, and their life was always cut short within 48 hours. I tried to get it established on various vegetables and fruit-trees, but it would not feed nor live on them.

There were Figs in the vineries, and the pest never touched them. Consequently my experience coincides with your own in that the Phylloxera will not deposit its eggs nor live in any other plant but the Vine.

"With regard to the eggs, I have kept roots and leaves with eggs and live insects all through the winter; but as soon as the sap of the leaves and roots was exhausted, the eggs became shrivelled and never produced live insects. I took pieces of roots infested with the insect and placed them in the soil into which clean Vines were potted, and in 14 days the roots of the pot-Vine were swarming with insects.

"Before I became sufficiently cognisant of the habits of the little devourer, the galls quite covered the under sides of hundreds of the young leaves, and the young wood was perfectly riddled with holes or punctures into which they had burrowed, feeding on the sap and depositing their eggs. I could compare their operations on the young wood to nothing but small-pox, so thick did they puncture it. The two following years I did not allow it to get ahead much, for I picked off and burned the infected leaves.

"I had the insect nearly as bad in the outside border as inside, but the borders were covered with leaves and strong wooden shutters from September to May, and were consequently comparatively dry and warm. There can be no doubt they thrive best in dry warm quarters, and they could be easily drowned, but the difficulty lies in getting at them. The small roots were eaten up. When lifting the Vines, I never found any larger than a thick quill, and the strong roots were infested up to the collars of the Vines".

Such are Mr Dunn's interesting remarks on this scourge. After trying numerous decoctions, such as salt and water, diluted turpentine, etc, he found that though it kept the insect in check, it could never be eradicated by such means without using the mixtures strong enough to kill the Vines too. He then lifted the Vines and cleansed them. He relates his method of doing so in the ' Transactions of the Horticultural Society.' "I closely pruned the young wood, stripped the stem clear of all loose bark, and then thoroughly washed them with a stiff brush and pure water. Having thus cleansed the tops, I began at the roots by lifting them carefully out of the soil and cutting away all the badly-infested parts, going patiently over those left and cutting clean off all spots of canker, showing where the insects were or had been, then washing them in the same manner as I had done the stems, going over them two or three times to make sure they were thoroughly clean, then dusting them over with an equal mixture of dry soot and newly-slaked lime, replanting them in some fresh soil, mixing a little soot and lime amongst it while filling it in, and taking care to pick out every morsel of old root or stick that could be seen.

I then washed the house thoroughly in every part, and painted it with spirits of turpentine to destroy any insects that might be missed in the washing, painting the Vine with the usual mixture of clay, soot, sulphur, soft-soap, and tobacco, adding two ounces of turpentine, and one of nux vomica to every gallon of the mixture, and then tied them in their places, leaving them alone until they broke into growth in April, which they did in a most satisfactory manner, and made strong growth during the summer, never showing the signs of an insect on either root or stem." This was done in 1868, and the Vines have prospered and kept free from Phylloxera, showing that Mr Dunn had done the work with a thoroughness which is characteristic of him. He is the only person who in this or any other country, that we are aware of, has thrown so much light on and destroyed this pest, at the same time successfully saving the Vines; and we have no hesitation in saying that if our London Horticultural, or any other Horticultural Society, can see their way to make him some reward for so successful an undertaking, that they will not be overstepping the limits of their duty.

No matter what course Mr Dunn might pursue in such a case again, the fact that he saved his Vines remains the same, and deserves more credit than he who, to destroy the pest, destroys the Vines also, although the latter procedure is doubtless attended with less uncertainty.

Editor.