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University of Nebraska - Lincoln

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Articles 1081 - 1110 of 1125

Full-Text Articles in Plant Pathology

Lack Of Effect Of Plant Growth-Regulators On The Action Of Alpha-Amylase Secreted By Virus Tumor Tissue, M. K. Brakke, L. G. Nickell Jan 1952

Lack Of Effect Of Plant Growth-Regulators On The Action Of Alpha-Amylase Secreted By Virus Tumor Tissue, M. K. Brakke, L. G. Nickell

Department of Plant Pathology: Faculty Publications

This report deals with the effect of certain synthetic plant growth-regulators on the activity of alpha-amylase (1) secreted by virus tumor tissue grown in vitro. Previous studies have lacked adequately controlled conditions and have been carried out with enzyme preparations obtained through the usual methods of destruction of cells. In this particular study (a) the assay employed to measure enzyme activity includes control of pH and temperature and (b) this enzyme, being secreted, is not subject to the drastic preparative procedures involving destruction of cellular structure usually necessary to obtain enzymes.

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Effect Of Low Temperature On The Germination Of Artificially Dried Seed Corn, J. E. Livingston Jan 1951

Effect Of Low Temperature On The Germination Of Artificially Dried Seed Corn, J. E. Livingston

Nebraska Agricultural Experiment Station: Historical Research Bulletins

Soil pathogens were primarily responsible for the reduction in emergence of corn seedlings following the cold treatment. The susceptibility of the seedlings to soil pathogens was much greater when the seedlings were exposed to a soil temperature of 5° C for 7 to 14 days than when they were held continuously at 20° C. Seedling emergence was in inverse relation to kernel moisture content at time of harvest. Artificial drying of the seed intensified this effect, particularly in nonsterile soil. Treatment of the seed with Arasan prior to planting completely eliminated the effect of soil pathogens on seedling emergence either …

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The Sedimentation Rate Of Potato Yellow-Dwarf Virus, M. K. Brakke, L. M. Black, Ralph W. G. Wyckoff Jan 1951

The Sedimentation Rate Of Potato Yellow-Dwarf Virus, M. K. Brakke, L. M. Black, Ralph W. G. Wyckoff

Department of Plant Pathology: Faculty Publications

BLACK et al. (1948) have published electron micrographs of bodies believed to represent the New York variety of potato yellow-dwarf virus (Aureogenus vastans (H) Black) (Holmes 1948). The photographs showed bodies in several different extracts of infected plants of Nicotiana rustica L., but not in corresponding preparations from healthy plants. Similar bodies were found in concentrates from plants infected with the New Jersey variety of the virus (var. agalliae Black). These bodies were larger than, and of a different character from, those of plant viruses hitherto examined in the electron microscope. The present study was undertaken to obtain evidence …

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Pink Rot Of Potatoes Caused By Phytophthora Erythroseptica Pethyb., R. W. Goss Jun 1949

Pink Rot Of Potatoes Caused By Phytophthora Erythroseptica Pethyb., R. W. Goss

Nebraska Agricultural Experiment Station: Historical Research Bulletins

During the summer of 1943 reports were received of rotted tubers occurring in fields of early potatoes in central Nebraska. An estimated 10 per cent of the tubers were found rotted in some fields on August 5. In November and December of the same year the late-producing area of western Nebraska reported the occurrence, at harvest and in storage, of tuber rots differing from those previously recorded for that area. Specimens appeared similar to those observed during the summer in central Nebraska. Isolations were made and pathogenicity tests were conducted both on tubers and growing plants to study the influence …

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Mechanical Transmission Of A Plant Tumor Virus To An Insect Vector, Karl Maramorosch, Myron K. Brakke, L. M. Black Jan 1949

Mechanical Transmission Of A Plant Tumor Virus To An Insect Vector, Karl Maramorosch, Myron K. Brakke, L. M. Black

Department of Plant Pathology: Faculty Publications

Most plant viruses transmitted by leafhoppers have not been demonstrated to be infective in extracts. The virus dealt with in this paper causes tumors in certain susceptible plants, is carried by leafhoppers, and like others in that group has proven difficult to detect in extracts. It is our purpose to recount briefly the variety of methods that failed to transmit the virus and to report on the success of insect-to-insect transmission by injection.

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Seed And Soil Treatments For Vegetable Crops Grown In Nebraska, M. W. Felton, J. E. Livingston Nov 1948

Seed And Soil Treatments For Vegetable Crops Grown In Nebraska, M. W. Felton, J. E. Livingston

Nebraska Agricultural Experiment Station: Historical Circulars

Tests conducted during the past four years at the Nebraska Agricultural Experiment Station have shown that when seeds are planted in cold, wet soils, better stands of vigorous seedlings are generally obtained when the seeds are treated before they are planted.

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Charcoal Rot Of Corn And Sorghum, J. E. Livingston Apr 1945

Charcoal Rot Of Corn And Sorghum, J. E. Livingston

Nebraska Agricultural Experiment Station: Historical Research Bulletins

In Nebraska, the charcoal rot caused considerable damage to the 1940 grain sorghum crop in the south central counties, and the following year it caused serious lodging and reduction of yield in both corn and sorghum in all sections of the state. Field observations indicated that some varieties of sorghum were damaged less than others; thus it appeared desirable to test thoroughly all varieties to determine whether any were sufficiently resistant to be recommended for field planting or to be used in a breeding program. It seemed desirable to study the influence of soil environment on infection and the development …

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Controlling The Ph Of Cultures Of Penicillium Notatum Through Its Carbon And Nitrogen Nutrition, Albert E. Dimond, George L. Peltier Jan 1945

Controlling The Ph Of Cultures Of Penicillium Notatum Through Its Carbon And Nitrogen Nutrition, Albert E. Dimond, George L. Peltier

Department of Plant Pathology: Faculty Publications

A survey of published material reveals relatively little information concerning the nutritional physiology of Penicillium notatum Westl. on synthetic media. Metabolism studies of P. notatum on various media have appeared to be incidental to the more pressing problem of producing penicillin quickly and in quantity. Fleming (1929) originally used a nutrient broth non-synthetic in nature. The Oxford group (Abraham et al., 1941) then adopted a modification of the so-called Czapek-Dox synthetic medium which supplies nitrogen as sodium nitrate and glucose as carbohydrate. Hobby, Meyer, and Chaffee (1942) suggested that brown sugar be substituted for glucose in this nutrient, with …

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Spraying Tree Fruits, C. C. Wiggans, E. H. Hoppert Mar 1940

Spraying Tree Fruits, C. C. Wiggans, E. H. Hoppert

Nebraska Agricultural Experiment Station: Historical Circulars

The production of sound, clean fruit is unquestionably one of the major problems facing the modern fruit grower. Culture may be neglected and pruning delayed for a time but the omission of sprays for even a single season demonstrates their absolute necessity. This applies equally to the commercial grower and to the farmer or gardener who has only a few trees.

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The Effects Of Stinking Smut (Bunt) And Seed Treatment Upon The Yield Of Winter Wheat, T. A. Kiesselbach, W. E. Lyness Apr 1939

The Effects Of Stinking Smut (Bunt) And Seed Treatment Upon The Yield Of Winter Wheat, T. A. Kiesselbach, W. E. Lyness

Nebraska Agricultural Experiment Station: Historical Research Bulletins

The depreciating effects of bunt or stinking smut (Tilletia levis Kuhn and tritici [Bjerk.] Wint.) upon the yield and quality of winter wheat in Nebraska and many other states are well known. The practical control of this disease through seed treatment has also been established and is being extensively practiced by growers. At the time these experiments were initiated in 1923, formaldehyde was the most commonly used disinfectant, while copper carbonate was just gaining recognition following its introduction by Darnell-Smith in 1915. It has been the chief purpose of the investigations herein reported to study the relative merits of …

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Comparative Physiology Of Actinomyces In Relation To Potato Scab, Mitrofan M. Afanasiev Aug 1937

Comparative Physiology Of Actinomyces In Relation To Potato Scab, Mitrofan M. Afanasiev

Nebraska Agricultural Experiment Station: Historical Research Bulletins

The present work was undertaken with the purpose of investigating the physiology of different strains of A. scabies as compared with saprophytic Actinomyces. By a comparative study of these groups, it was thought that differences in the physiology of the two might be found which would give a better understanding of the nature of this parasitism and also of the metabolism of Actinomyces in general. In addition, it was hoped that the determination of the factors influencing the parasitism of Actinomyces might establish a basis for the development of more efficient methods of controlling scab diseases. The present investigation …

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The Influence Of Various Soil Factors Upon Potato Scab Caused By Actinomyces Scabies, R. W. Goss Aug 1937

The Influence Of Various Soil Factors Upon Potato Scab Caused By Actinomyces Scabies, R. W. Goss

Nebraska Agricultural Experiment Station: Historical Research Bulletins

Scab, caused by Actinomyces scabies (Thaxt.) Giiss., is a potato disease of major importance in western Nebraska. Seed treatments are effective in controlling seed-borne scab, but it has been shown that even when healthy or treated seed potatoes are used the disease may be very severe because of infection from the soil. Crop rotation will reduce the incidence of the disease, but the fact that potato scab may cause serious loss in soils never before planted to potatoes indicates that there are numerous factors other than the time interval between potato crops which affect the occurrence of the disease. A …

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Wilt And Cold Resistance Of Self-Fertilized Lines Of Alfalfas, George L. Peltier, H. M. Tysdal Sep 1934

Wilt And Cold Resistance Of Self-Fertilized Lines Of Alfalfas, George L. Peltier, H. M. Tysdal

Nebraska Agricultural Experiment Station: Historical Research Bulletins

The relative reactions to cold and wilt of self-fertilized lines of alfalfa through to the fifth generation are reported. Some of the reasons for undertaking a breeding program are given as well as methods used in the controlled cold and wilt determinations. Preliminary studies showed that reinoculating healthy individuals which had already resisted one wilt infection test served to eliminate additional plants, but the percentage healthy was much higher after the reinoculation than after the first inoculation. The foundation materials from which selections were made consisted of selected plants from a number of old Nebraska fields and a large collection …

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Cephalosporium Wilt And Die-Back Of The White Elm, R. W. Goss, Paul Raymond Frink Jan 1934

Cephalosporium Wilt And Die-Back Of The White Elm, R. W. Goss, Paul Raymond Frink

Nebraska Agricultural Experiment Station: Historical Research Bulletins

A new disease of the white elm has been found to be common in eastern Nebraska. The causal organism has been isolated and its pathogenicity proved by inoculation. The fungus belongs to the genus Cephalosporium and is considered to be the same as that described by Curtis May of Ohio and found by him in specimens obtained in Iowa, Missouri, New York, and Washington, D.C. The morphology and cultural characters of the organism are described.

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The Relative Susceptibility Of Alfalfas To Wilt, George L. Peltier Apr 1933

The Relative Susceptibility Of Alfalfas To Wilt, George L. Peltier

Nebraska Agricultural Experiment Station: Historical Research Bulletins

Except for alfalfa seed originating from a few old fields of Turkestan and Ladak, all varieties and strains now grown for commercial seed production in the United States, so far tested, have proved susceptible to wilt. All seed lots tested from South America (Chile, Argentina, and Uruguay), Europe (France, Spain, Portugal, Germany, Hungary, Italy, Roumania, and Ukranian S.S.R.), Africa (Morocco, Algeria, and Abyssinia), and Asia (Palestine, Manchuria, China, Korea, and Chinese Turkestan) were found to be susceptible to wilt. All seed lots of Turkestan origin so far tested are as resistant as Hardistan, or more so. Seed samples from the …

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The Nature Of Resistance In Alfalfa To Wilt (Aplanobacter Insidiosum L. Mc.), George L. Peltier, F. R. Schroeder Oct 1932

The Nature Of Resistance In Alfalfa To Wilt (Aplanobacter Insidiosum L. Mc.), George L. Peltier, F. R. Schroeder

Nebraska Agricultural Experiment Station: Historical Research Bulletins

Alfalfa wilt was first discovered in 1924 in southern Wisconsin and northern Illinois. The causal organism, Aplanobacter insidiosum, was later described by McCulloch. Since that time wilt has been reported from most of the alfalfa-growing sections of the United States and in some states it has been responsible for a rapid decrease in the acreage of alfalfa. During the past three years a number of investigators have found that certain alfalfas are somewhat resistant to wilt, whereas others are very susceptible. At the Nebraska station the results to date indicate that all common and most variegated alfalfas are very …

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Tuber Development In Triumph Potatoes As Influenced By Time Of Planting On Dry Land In Northwestern Nebraska, H. O. Werner May 1932

Tuber Development In Triumph Potatoes As Influenced By Time Of Planting On Dry Land In Northwestern Nebraska, H. O. Werner

Nebraska Agricultural Experiment Station: Historical Research Bulletins

Triumph potatoes were planted on four different dates during six years in order to determine the best planting date on dry land in northwestern Nebraska, where this variety is grown primarily for seed. Features considered in comparing the merits of these planting dates were: stand of plants; vine growth; disease prevalence; time of plant maturity; number, size, and shape of tubers; cracking at harvest time; prevalence and severity of common scab; total yields and yields of various grades of potatoes from various harvesting dates; weight loss in storage; and duration of the dormant period. The experimental aspects dealing with the …

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Infection Experiments With Spindle Tuber And Unmottled Curly Dwarf Of The Potato, R. W. Goss Feb 1931

Infection Experiments With Spindle Tuber And Unmottled Curly Dwarf Of The Potato, R. W. Goss

Nebraska Agricultural Experiment Station: Historical Research Bulletins

It is probable that more than one insect species are capable of spreading some of the potato virus diseases. This conclusion was also indicated by repeated observations in the dry-land section of western Nebraska. While aphids are abundant and are probably the chief vectors of potato virus diseases in the more humid sections of the country, they are usually scarce in the western upland plains area and are not present in large enough numbers to account for the rapid spread of spindle tuber and unmottled curly dwarf which sometimes occurs. It was therefore considered advisable to determine the common potato …

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The Relative Susceptibility Of Alfalfas To Wilt And Cold, George L. Peltier, H. M. Tysdal Dec 1930

The Relative Susceptibility Of Alfalfas To Wilt And Cold, George L. Peltier, H. M. Tysdal

Nebraska Agricultural Experiment Station: Historical Research Bulletins

The final solution of the alfalfa-wilt problem in Nebraska probably lies in the development of resistant sorts that are winterhardy as well as productive. The relative susceptibility to wilt of 40 lots from Turkestan, 10 from France, 6 of Grimm from as many states, and 16 domestic alfalfas are reported on at this time, together with hardiness tests of a few well-known varieties and strains and the more recent introductions from Turkestan and France.

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Breeding Winter Wheat For Resistance To Stinking Smut (Tilletia Levis And Tilletia Tritici), T. A. Kiesselbach, Arthur Anderson Dec 1930

Breeding Winter Wheat For Resistance To Stinking Smut (Tilletia Levis And Tilletia Tritici), T. A. Kiesselbach, Arthur Anderson

Nebraska Agricultural Experiment Station: Historical Research Bulletins

Several productive lines of hard red winter wheat which are highly resistant to both species of stinking smut (Tilletia levis and T. tritici) have been isolated from the Turkey variety. Artificial-smut and stem-rust epidemics and controlled freezing have been found useful supplements to field-performance tests. Differential reactions of the new Turkey selections and a number of hybrid selections and established resistant varieties to collections of bunt from a number of states give definite evidence of the occurrence of mild and virulent physiologic forms of both species. Certain selections have proved very resistant to some of the smut collections and …

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The Symptoms Of Spindle Tuber And Unmottled Curly Dwarf Of The Potato, R. W. Goss May 1930

The Symptoms Of Spindle Tuber And Unmottled Curly Dwarf Of The Potato, R. W. Goss

Nebraska Agricultural Experiment Station: Historical Research Bulletins

The differentiation of the virus diseases of the potato on the basis of symptoms is an important but difficult phase of the virus problem. A knowledge of the variation in symptoms due to environmental factors is necessary both in investigational work and in the practical application of our knowledge to the control of these diseases in the field. A fairly comprehensive knowledge of the masking effect of certain environmental factors upon the symptoms of the mosaic group has been obtained through the work of various investigators. Considerably less information is available concerning the effect of environment upon the symptoms of …

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Seed Potato Treatment Tests For Control Of Scab And Rhizoctonia, R. W. Goss, H. O. Werner Dec 1929

Seed Potato Treatment Tests For Control Of Scab And Rhizoctonia, R. W. Goss, H. O. Werner

Nebraska Agricultural Experiment Station: Historical Research Bulletins

Potato scab annually takes a very large toll from the potato growers of Nebraska. Rhizoctonia causes considerable loss each year, particularly in the early-potato sections, where it decreases stand and yield. These losses are caused by infection from both the soil and the seed. The investigations reported in this paper deal only with the control of the infection arising from the seed. Even though potato seed treatments have been recommended for many years, the diversity of recommendations being made at present by various agencies is very confusing to the grower and research worker alike. Many of the reports from different …

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Effect Of Cultural Methods And Maturity Upon The Seed Value Of Eastern Nebraska Potatoes, H. O. Werner Dec 1929

Effect Of Cultural Methods And Maturity Upon The Seed Value Of Eastern Nebraska Potatoes, H. O. Werner

Nebraska Agricultural Experiment Station: Historical Research Bulletins

Seed potatoes as good as northern stocks have been produced under a straw mulch in eastern Nebraska by experimenters and growers. Occasionally reports are heard that a lot of seed potatoes has been grown in eastern Nebraska by ordinary cultural methods for many years, apparently without loss of vigor or yielding capacity. In view of this situation it seemed advisable to investigate this problem to determine whether, and to what extent, environment and maturity as such influence the productivity of seed potatoes and also whether it is feasible to produce satisfactory seed potatoes in the southern and eastern portions of …

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A Research Delusion, George L. Peltier Jan 1928

A Research Delusion, George L. Peltier

Department of Plant Pathology: Faculty Publications

With the administrative heads of many of our educational institutions demanding a doctorate of every member of the permanent staff, as it is supposed to be a prerogative for research, and the issuing of a list of titles published each year by their staff, the urge for so-called research, namely, a list of titles, goes madly on. In fact publication sometimes becomes a sort of self-defense, for the absence of any titles over a brief period of years stamps one either as lacking the ability of doing research or inefficient. Likewise, such a policy has permeated the staff, so that …

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Stem Rust In Nebraska. Part I. General Survey Of Sources. Part Ii. Identification Of The Physiologic Forms Of Puccinia Graminis From Various Sources, George L. Peltier, A. F. Thiel Jul 1927

Stem Rust In Nebraska. Part I. General Survey Of Sources. Part Ii. Identification Of The Physiologic Forms Of Puccinia Graminis From Various Sources, George L. Peltier, A. F. Thiel

Nebraska Agricultural Experiment Station: Historical Research Bulletins

Part I: Since the inception of the barberry eradication campaign in 1918 in Nebraska, the question has continually been asked, "Will the eradication of the barberry in the state eliminate or materially reduce stem rust?" In order that an answer might be obtained, an investigation to determine the sources of primary infection of stem rust on cereals was inaugurated in the spring of 1921. Although these studies have been carried on for 6 years, no definite statement regarding the relative importance of the primary sources and the amount of stem rust prevalent in the state from season to season originating …

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The Differential Reaction Of Strains Within A Variety Of Wheat To Physiologic Forms Of Puccinia Graminis Tritici, T. A. Kiesselbach, George L. Peltier Dec 1926

The Differential Reaction Of Strains Within A Variety Of Wheat To Physiologic Forms Of Puccinia Graminis Tritici, T. A. Kiesselbach, George L. Peltier

Nebraska Agricultural Experiment Station: Historical Research Bulletins

Black stem rust of wheat (Puccinia graminis tritici (Pers.) Erikss. & Henn.), which occurs in Nebraska and thruout most of the wheat producing regions of the world, is of a composite nature, in that it consists of a number of physiologic forms which can be determined by their action on different varieties of Triticum species, as shown by Stakman and Levine. The ordinary commercial variety of wheat may likewise be regarded as a mixture, in that it consists of numerous strains, which differ in some more or less important characteristics, as has been frequently indicated in the literature concerning …

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The Spindle-Tuber Disease As A Factor In Seed Potato Production, H. O. Werner May 1926

The Spindle-Tuber Disease As A Factor In Seed Potato Production, H. O. Werner

Nebraska Agricultural Experiment Station: Historical Research Bulletins

The lines of experimentation that supplied the data herein reported, stated in very general terms, were as follows: (1) Tuber-line selection studies (2) Relation of environmental conditions to seed-potato production (3) Seed-potato strain trials of certified and uncertified stock (4) Spindle-tuber transmission experiments. Most of these general lines of experimentation will not be completely discussed as a unit in any one part of the bulletin. For the sake of clarity, consecutive thought, and elimination of repetition, data will be selected from any experiment for insertion and discussion under the most logical heading in any part of the bulletin. Unless otherwise …

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Winter Wheat Investigations, T. A. Kiesselbach Nov 1925

Winter Wheat Investigations, T. A. Kiesselbach

Nebraska Agricultural Experiment Station: Historical Research Bulletins

Twenty years of wheat breeding, consisting chiefly of the isolation and testing of pure lines, has now been conducted at the Nebraska Agricultural Experiment Station. It is the purpose of this paper to report the conduct and results of this work. The resulting strains are compared with the best other wheats available from Nebraska and other sources. The effects of a number of cultural practices related to the preparation of seed, seeding, treatment of the growing crop, and harvesting are also presented. Some consideration is given to the experimental technique of the comparative tests.

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A Study Of The Environmental Conditions Influencing The Development Of Stem Rust In The Absence Of An Alternate Host. Iv. Overwintering Of Urediniospores Of Puccinia Graminis Tritici. V. The Period Of Initial Infection Of Urediniospores Of Puccinia Graminis Tritici On Wheat. Vi. Influence Of Light On Infection And Subsequent Development Of Urediniospores Of Puccinia Graminis Tritici On Wheat, George L. Peltier Nov 1925

A Study Of The Environmental Conditions Influencing The Development Of Stem Rust In The Absence Of An Alternate Host. Iv. Overwintering Of Urediniospores Of Puccinia Graminis Tritici. V. The Period Of Initial Infection Of Urediniospores Of Puccinia Graminis Tritici On Wheat. Vi. Influence Of Light On Infection And Subsequent Development Of Urediniospores Of Puccinia Graminis Tritici On Wheat, George L. Peltier

Nebraska Agricultural Experiment Station: Historical Research Bulletins

IV. In order to ascertain whether the urediniospores of Puccinia graminis tritici (Pers.) Erikss. and Henn. overwinter under the environmental conditions prevailing at Lincoln, Nebraska, a series of experiments was carried out extending over a period of 5 years. The results of this investigation are briefly presented. V. By the period of initial infection is meant the time required by a pathogen after it reaches a susceptible plant part to enter the tissues. To determine what the period of initial infection of urediniospores of Puccinia graminis tritici might be, experiments were undertaken during the season of 1923-24 using urediniospores of …

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A Study Of The Environmental Conditions Influencing The Development Of Stem Rust In The Absence Of An Alternate Host. Iii. Further Studies Of The Viability Of Urediniospores Of Puccinia Graminis Tritici, George L. Peltier Oct 1925

A Study Of The Environmental Conditions Influencing The Development Of Stem Rust In The Absence Of An Alternate Host. Iii. Further Studies Of The Viability Of Urediniospores Of Puccinia Graminis Tritici, George L. Peltier

Nebraska Agricultural Experiment Station: Historical Research Bulletins

1. The influence of relative humidity and temperature on the viability of the urediniospores of two Physiologic Forms of Puccinia graminis tritici has been determined. 2. The same general relation between the viability of the urediniospores and the relative humidity and temperature was found, namely, that the lower the temperature the longer the spores retained their viability at all relative humidities, while at any stated temperature the spores were viable the longest at the medium humidities. 3. Urediniospores of Physiologic Form XXI held at 49.0 per cent relative humidity and maintained at a temperature of 5° C. when tested for …

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