This section is from the book "The Gardener's Monthly And Horticulturist V26", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
" O. E.," Philadelphia, says: " At a recent meeting of the Montgomery county, O., Society, Mr. H. C. Smith stated that pitch tar was found to be more dangerous than coal tar to keep insects from injuring the bark of trees. This is very important information, as the general belief has been the reverse.' This is from the Gardeners' Monthly, March, 1882, but it does not elucidate the matter clearly. Can you throw more light on it?"
[We called attention to the matter at the time merely as information, but have learned nothing further since. It was at one time recommended that a little coal tar should be painted around fruit trees at the collar, as a sure means of keeping out borers and preventing mice and rabbits from barking them. We had seen coal tar so employed serving the purpose admirably, and not injuring the trees in the slightest degree. Then came reports that trees had been injured, and it was surmised that some coal tar had too much creosote in it, which is known to be injurious to vegetation, and it was believed that pine tar would be free from this objection. It would be well worth while for any who may have had experience to tell what they know about it. There have been some very successful experiments of late made by using tar water against green fly and other insects, but we do not know anything from our own experience. Tar in most of its forms is liable to be injurious to vegetation, but in skilful hands it ought to be of very great value. - Ed. G. M].