_Sir_--I observe in your _Plough Boy_ of the 1st inst. some observations on the disease in Plum Trees, called _Canker_, wherein the writer states that the disease is probably caused by the trees being bark-bound. I have had sufficient proof to convince me that it is caused by insects only. From a variety of observations and experiments, I find that when young shoots are throwing out of the trees, they are stung by a species of fly, and a number of eggs or nits are deposited through the tender bark, where they remain until the tree commences growing the next season; those places then begin to swell, and after a few weeks, small worms can be distinctly observed by the naked eye, which, after about one month more is elapsed, eat out of the protuberances, then become black, take to themselves wings, and commence operations as before stated. The only remedy that I can discover, is to cut off every limb affected, on its first appearance; and if the tree be so much affected as to be past cure, it should be totally cut down, in order to destroy the whole race of insects which cause the disease. The first discovery of this complaint was on the sea-board: and it has advanced north about twenty miles a year. At present nearly all the bearing trees on the sea coast to the southeast, are totally destroyed, and it pervades all this part of the country. The poorest natural blue plums are first attacked--the dark coloured grafts, next--and lastly, the light coloured fruit fall victims. Some few kinds as yet withstand their attacks. By observing the above caution, my trees are entirely free from them, and bear abundantly. I am, Sir, Yours, &c. ARBOREUM. ON DOMESTIC MANUFACTURES. SIR--The Montgomery Agricultural Society have announced the following 40 premiums to be awarded to ladies in October, 1820. As some of them are novel, their publication in the Plough Boy, I am persuaded, will have an excellent effect, as an example. W. * * * * * To the lady who shall produce the best piece of cloth, made of merino wool, spun in the family, not less than 15 yards, $8 2d best do. 6 For the best piece of cloth made of common wool, spun in the family, not less than 15 yards, 6 2d best do. 4 For the best piece of flannel, spun in the family, of merino wool, not less than 20 yards, 6 2d best do. 4 For the best piece of flannel made of common wool, spun in the family, not less than 20 yards, 5 2d best do. 4 For the best pair of rose blankets, spun and made in the county, 5 2d best do. 4 For the best piece of carpeting, spun in the family, 6