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Full-Text Articles in Life Sciences

Effects Of Metepa On Gametogenesis And Embryogenesis In The Large Milkweed Bug Oncopeltus Fasciatus (Dallas), Donald E. Lawson, Harold J. Ball Sep 1969

Effects Of Metepa On Gametogenesis And Embryogenesis In The Large Milkweed Bug Oncopeltus Fasciatus (Dallas), Donald E. Lawson, Harold J. Ball

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

Considerable research is currently being directed toward discovering means of controlling insects other than by applying insecticides. There are several promising concepts of control which minimize the use of insecticides and one of these is the use of sterilizing techniques. Some emphasis is currently being placed on the development of chemosterilant techniques. Many of the studies have been concerned with the screening of potentially active chemicals, whereas other research has dealt with the efficacy of field application. The more basic work has been accomplished through the participation of several disciplines. The purpose of this study was to characterize the effects …


Western Ironweed: Research On Anatomy, Physiology, Life History And Control, M. K. Mccarty, C. J. Scifres Apr 1969

Western Ironweed: Research On Anatomy, Physiology, Life History And Control, M. K. Mccarty, C. J. Scifres

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

Western ironweed (Vernonia baldwini Torr.) is a member of a widespread and diverse genus. The genus is characterized by perennial herbs and shrubs. Weaver and Darland listed the increase of western ironweed, at one time sparsely distributed, as an indication of degeneration of the true prairie. They described the invasion, spread, and ultimate dominance of western ironweed in many pastures after the drought years. Weaver measured ironweed roots to a depth of 11 or 12 ft., and remarked that it was one of "the most abundant and worst weeds in native pastures derived from the true prairie." Research has …


Calf Diarrhea (Scours): Reproduced With A Virus From A Field Outbreak, C. A. Mebus, N. R. Underdahl, M. B. Rhodes, M. J. Twiehaus Mar 1969

Calf Diarrhea (Scours): Reproduced With A Virus From A Field Outbreak, C. A. Mebus, N. R. Underdahl, M. B. Rhodes, M. J. Twiehaus

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

Neonatal calf diarrhea typical of that seen in field cases was produced in colostrum-deprived calves by inoculating either feces or bacteria-free filtrates via the duodenum, orally, or by a spray (aerosol). Three calves, kept free of E. coli, developed severe diarrhea following inoculation with a bacteria-free filtrate. Intense fluorescence in the epithelium of sections of small intestine from two experimental calves was observed following staining with ftuorescein-labeled gamma globulin produced with viral antigen prepared from the feces of two experimental diarrhetic E. coli-free calves. Fluorescing cells were also present in the feces of experimental and field cases of neonatal …


Some Factors Affecting Germination And Seedling Growth Of Scotch Thistle, C. J. Scifres, M. K. Mccarty Feb 1969

Some Factors Affecting Germination And Seedling Growth Of Scotch Thistle, C. J. Scifres, M. K. Mccarty

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

Scotch thistle (Onopordum acanthium L.) is a native of Eurasia. Scotch thistle is found in the grasslands of central Nebraska, with heaviest infestations in Gosper, Dawson, and Valley Counties and limited occurrence in 18 additional counties. The Nebraska Unicameral declared it a noxious weed in 1965. This study measures the effects of some environmental factors on scotch thistle germination and seedling growth, and clarifies some of the interactions of these with inherent characteristics of the achene. The effect of achene coat, stratification, light, temperature, growth regulators, pH, depth of planting, salinity, germination inhibitors, and moisture stress were studied.


Germination And Early Seedling Development Of Musk And Plumeless Thistle, M. K. Mccarty, C. J. Scifres, A. L. Smith, G. L. Horst Feb 1969

Germination And Early Seedling Development Of Musk And Plumeless Thistle, M. K. Mccarty, C. J. Scifres, A. L. Smith, G. L. Horst

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

The present study was conducted to determine the effects of some simulated environmental variables on the germination of musk and plumeless thistle achenes. The two species appear to occupy a somewhat similar role in the natural vegetation, and a direct comparison of germination characteristics was sought.


The Biology And Ecology Of Trogoderma Glabrum (Herbst) In Stored Grains, Benjamin H. Kantack, Robert Staples Feb 1969

The Biology And Ecology Of Trogoderma Glabrum (Herbst) In Stored Grains, Benjamin H. Kantack, Robert Staples

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

These investigations were undertaken to determine the distribution and importance of Trogoderma glabrum (Herbst) in stored grain in Nebraska, the ecological factors favoring population increase in stored wheat, corn, and sorghum, and the role T. glabrum might play in disseminating internally the Aspergillus molds commonly encountered in stored grain.


Life Cycle Studies With Musk Thistle, M. K. Mccarty, C. J. Scifres Jan 1969

Life Cycle Studies With Musk Thistle, M. K. Mccarty, C. J. Scifres

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

Musk thistle (Carduus nutans L.) was added to the Nebraska noxious weed list in 1959. The objectives of this study were: (a) to determine the normal life cycle of musk thistle in Nebraska; (b) to determine the variations from the normal life cycle of musk thistle; and (c) to furnish a summary of the phenology for musk thistle in southeastern Nebraska. Observations are used freely throughout the text to describe morphological variations occurring within musk thistle that are not easily quantified.