Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 55-60). Also available via the Internet.

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The Cocco idea or scale insects are among the most important pests of sylvicultural, ornamental, agricultural and greenhouse plantings throughout the world. There are 21 families comprising 6,000 species. Direct injury occurs from the withdrawal of sap while feeding and from the production of galls. Some scale insects are host specific while others are polyphagous. They feed on many different parts of plants including the roots, trunk, stems, leaves, buds and fruit. / Ph. D.

Morphological studies in the past have been almost exclusively confined to the description and illustration of adult females. Morphological studies of Diaspididae were further restricted to the pygidial area. This study is an attempt to provide complete descriptions, illustrations, and measurements for morphological characters for all life stages of C. americana Johnson and C. kosztarabi Takagi and Kawai. The majority of the specimens were obtained from weekly collections of local infestations on the Virginia Polytechnic Institute and State University campus. Freshly collected scale insect samples were mounted in both Hoyer's medium and Canada balsam for microscopic study. The biologies of the two species in Blacksburg, Virginia were studied using weekly collections. Both species were bivoltine. C. americana overwintered mainly in the egg stage; the first brood hatched about April 20, and the second brood about July 25, in 1972. C. kosztarabi overwintered as fertilized females. Eggs were laid in early spring hatching about May 28 in 1973, and the eggs of the second generation began hatching about August 10, in 1972. Dimorphic males of both species were collected. C. americana males exhibited apterous and brachypterous conditions. C. kosztarabi males were either apterous or pterous. Several species of hymenopterous parasites were reared from each species. / Master of Science

Thesis (M.S.) -- University of Tennessee, Knoxville, 2006. / Title from title page screen (viewed on Feb. 5, 2007). Thesis advisor: Paris Lambdin. Vita. Includes bibliographical references.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

In order that the citrus industry in South Africa may be commercially developed to the greatest possible extent it is of importance that certain basic ecological problems should be investigated. Until the complex relationships between the host plant, the insect pests and their parasites and predators are known, the results of applications of either chemical or biological control must be largely a matter of chance. A certain amount of rather generalised work in this connection has already been done in South Africa, principally by Carnegie (1955), Smithers (1953) and Whitehead (1948) in the Eastern Cape Province and by Steyn (1954) in the Transvaal. The first three of these workers were content to determine which species of insects occurred in citrus orchards and made some attempts to study the biology of certain predators. Steyn went a little further when he correlated ant activity with scale insect infestations. Without doubt the most economically important insect pests of citrus are the scale insects (Homoptera: Coccoidea). Introduction, p. 1.

The citrus industry is subject to a number of serious insect pests. Of these, the most important is a sedentary group known as the Armoured Scale Insects (Diaspididae). Ebeling (1950) states that they are of greater economic importance to the industry than all the other pests put together. A great deal has been published on various aspects of the biology, ecology and control of the Diaspididae, much of the work appearing in the books of Quayle (1938), Ebeling (1950) and Bodenheimer (1951). It is very noticeable, however, that the study of the active larvae, or "crawlers", of these insects has been relatively neglected. This lack of work on crawlers is surprising, since they are the only distributive stage in the life cycle of the species. The adult male is also free-living during its brief life span, but takes no part in the actual distribution of the species. It is the position of the female Scale Insect which is important in determining the further spread of the species, since this is the point from which subsequent crawlers will start out on their wanderings. The stage in the life cycle responsible for the position of the female is, of course, the crawler. The crawler is also responsible for the parallel distribution of the male Scales, so that the female can be fertilised. The role of the adult male is confined to the maintenance of the gene flow. From an economic point of view it seems desirable that a complete study be made of the biology of this distributive stage of these important pests.

Scale insects are among the most serious plant pests throughout the world. The Diaspididae is the largest scale insect family and probably the most important economically. No comprehensive taxonomic study dealing with the scale insects of Venezuela has been conducted in the past. Forty-nine species are described and illustrated in this study, of which 2 are new species. Twenty-seven additional species are recorded from Venezuela for the first time. Keys are provided for determination of the 49 species. The material studied was borrowed from several institutions. Mounting techniques are given. The description of each species is based on females, since males and nymphs were available only in a few species. While this is essentially a taxonomic and faunistic study, the hosts on which the scale insects were found are listed. It is hoped that this study would be used as basis for future research in Venezuela. More collections need to be made throughout the many ecologically different areas of the country; especially from non-cultivated plants. The accumulation of additional distributional and biological records, and will lead to a better understanding of the Venezuelan armored scale insect fauna. / Ph. D.