San Jose Scale And Its Nearest Allies

Author : Theodore Dru A. Cockerell
Publisher :
ISBN 13 : 9781331978879
Total Pages : 38 pages
Book Rating : 4.9/5 (788 download)

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Download or read book The San Jose Scale and Its Nearest Allies written by Theodore Dru A. Cockerell and published by . This book was released on 2015-07-22 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from The San Jose Scale and Its Nearest Allies: A Brief Consideration of the Characters Which Distinguish These Closely Related Injurious Scale Insects Suppose that some objects suspected to be San Jose scales have been found upon a fruit tree. The first thing to do is to ascertain whether they are scales (Coccidae) at all. I have known fly marks to be taken for Coccidae, and occasionally the lenticels on the young growth of trees are supposed to be scale insects by those whose experience ought to have taught them better. It is really remarkable how the lenticels on cotton wood twigs in the Mesilla Valley, N. Mex., resemble a scale prevalent in that locality, Aspidiotus juglans-regiw var. albus. From a short distance the deception would be complete but for the fact that the lenticels are arranged at approximately equal distances from one another and not massed like scale insects. Still more like coccids are certain fungi; I have on occasion been obliged to use a lens to ascertain which I had before me. At Mesilla, N. Mex., I found on the dead wood of an apple tree a fungus which closely resembled the second stage, or immature male scales of the San Jose scale. This fungus was kindly identified for me by Mr. J. B. Ellis as the cytispora stage of Valsa ambiens Persoon. It is presumed that no entomologist will be misled for more than a moment by lenticels or fungi, but for those who are not entomologists it may be recommended to scrape the object with the finger nail or a knife blade, when, if it is a scale insect, it will readily come away, leaving at most only a pale film. Granting now that we certainly have a scale insect before us, it is to be learned whether it belongs to the subfamily Diaspinae. A mealybug has no scale - only some mealy or cottony secretion; a Lecanium or shield scale is itself the scale that is, the insect becomes hardened and scale - like, but has no scale separable from its body. But the Diaspinae are small soft insects, in the adult 9 stage without legs and unable to move, which secrete a scale separate from themselves, much like the shell of an oyster. With a lens it is easy to make out the insect and its scale, the latter having first been overturned with the point of a knife. The scale, it is further seen, carries the exuviae of the two first stages, or only one if it be a male. Now, then, if we are sure that we have a Diaspine is it an Aspidiotus - the genus of the San Jose scale! In Aspidiotus the female scales are round, or nearly so, and the male scales vary from round to oval, according to the species, but are always of a similar texture to those of the female. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works."