Bulletin of the U.S. Department of Agriculture Volume 1-13 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1914 Excerpt: ...so soon and so freely, and were so free from disease that most horticulturists felt sure that acacias would become the most important shade trees for California. This enthusiasm was particularly marked from 1870 to 1876. It was like the subsequent fad in the Middle West for the hardy catalpa or the more recent furore over eucalypts in California. There followed, however, a sharp reaction because of the ravages of various scale insects, and many trees were cut down. But after the introduction of the vedalia, which destroyed the cottony cushion scale, and the adoption of the various sprays it was found that the acacias are not peculiarly subject to injury by scale insects, and are no more often a haven for the pests than are oaks, olives, and various orchard trees. The most dangerous insect enemy, 'J. H. Maiden, "Wattles and Wattle Barks," Government Printer, Sydney, New South Wales. 2 For information on insects and methods for their control the reader should apply to the State Experiment Station, iierkeley, Cat, or to the Bureau of Entomology, United States Department of Agriculture, Washington, D. C. according to various observations, is the cottony cushion scale (leerya purchasi). The scale insects have sucking mouthparts and subsist on the juices from the inside of the tree; for this reason they are hard to combat, because it is difficult to poison their food supply. Since they live upon the sap, they must necessarily lessen the vitality of a tree, especially where there is a very dry summer climate. If they are very numerous, trees can not thrive and may even be killed. Scale insects, besides robbing the tree of nourishment, harm the tissues, close the pores by their excretions, and supply conditions under which fungi may get a good start. All ...