Plant Pathology Commons^™

Expression Analysis Of Plant Defense Responses During The Establishment Of Biotrophy And Role Of Abiotic Stress In The Infection Of Dyer’S Woad (Isatis Tinctoria) By Puccinia Thlaspeos, Elizabeth Thomas

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The kinetics and amplitude of the salicylic acid-responsive pathogenesis-related (PR) genes and the cytochrome P450 gene ItCYP79B2 in the compatible interaction between Puccinia thlaspeos and dyer’s woad (Isatis tinctoria) during the first 72 hours of inoculation were examined. Immediately following penetration of the host by the rust pathogen, there was a modest up-regulation of PR genes but a significant down-regulation of ItCYP79B2 expression. During haustoria formation, a significant pathogen-mediated suppression of PR genes was observed with a corresponding up-regulation of ItCYP79B2. This potentially facilitates haustoria formation by P. thlaspeos. After haustoria formation, a more …

The Isolation, Property Analysis And Determination Of In Planta Growth Ability Of Extracellular Polysaccharide Mutants Of Corynebacterium Michiganense Pv Insidiosum, Mary C. Paschke

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Corynebacterium michiganense pv insidiosum, the organism responsible for bacterial wilt of alfalfa, produces an extracellular polysaccharide (EPS) that has been linked to its virulence. The EPS is composed of three different-sized molecules (components I, II and III). It has been demonstrated that this EPS accumulates in the vascular system of infected plants and causes disruption of the flow of water.

The importance of EPS to the survival and pathogenicity of C.m. pv insidiosumis not known. In order to begin assessing the value of EPS, mutant strains that are EPS-deficient were isolated after UV mutagenisis. Analysis by gel filtration …

Source Of Inoculum, Yield And Quality Of Tomato As Affected By Leveillula Taurica, Wayne B. Jones

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Tomato transplant stock from southern Nevada served as a source of inoculum and developed disease symptoms of tomato powdery mildew approximately three weeks before Utah-grown transplants. Plants from Nevada and Utah were equally infected seven weeks after planting and no differences in severity or yield were detected at the end of the season due to rapid spread of the fungus. Tomato yields were reduced ca 40% in check plots when compared to plots treated with triadimefon, propiconazol or sulfur. The amount of sunburned fruit in check plots was three to four times greater than in plots where the disease was …

Impact, Epidemiology And Control Of Crown And Root Rot Of Spring Barley In Utah, Rastri Dey Kidambi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A three year study was initiated to study impact, epidemiology and control aspects of crown and root rot of irrigated and dryland spring barley in Utah. Isolations from leading edges of necrotic lesions of infected plants showed Cochliobolus sativus to be most frequently isolated. Yield loss studies showed that the disease had it's greatest effect in kernel weight reduction.

Time course studies of disease initiation, development and progress were made throughout two consecutive growing seasons. Disease initiation began 25-30 days after planting and reached maximum levels at approximately 60-80 days. Soil inoculum levels were determined by the flotation viability method …

Crown And Root Rot Of Alfalfa In Utah, Victoria Allard Turner

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Symptoms of dark crown necrosis were found in all fields and varieties of alfalfa examined throughout the state. No significant differences were noted among varieties in 1 year old test plots in the amount of disease (Disease Index = D.I.) present in crown tissue. Significant differences were noted in plots 2.4 years and older among the different varieties. Varieties common to all plots did not differ overall; however, varieties responded differently according to location.

Fusarium spp. were most frequently isolated from affected crowns throughout the state, yet, differences in occurrence of species among the different aged plots and fields were …

In Vitro Morphogenesis And Mutation Of Glycine Max L., Thomas Daniel Wilson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Soybean (Glycine max L. c.v. Consoy) tissue cultures were grown in synthetic media containing various concentrations and combinations of minerals, auxins, cytokinins, pH levels, and inorganic growth factors in a systematic procedure to establish optimum media for initiation and maintenance of callus. Further modification of the hormone level was employed to initiate callus morphogenesis. Normally toxic levels of atrazine were established in soybean calli media, and ethyl methanesulfonate (EMS) and X ray-induced mutant calli were selected for atrazine tolerance.

Optimal media for initiation and maintenance of soybean calli were developed and a defined medium was determined that consistently yields …

Multiple Forms Of Deoxyribonucleic Acid-Dependent Ribonucleic Acid Polymerase In Barley Leaves (Hordeum Vulgare L.), Sachchidananda Javali

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Ribonucleic acid polymerases (E.C. 2.7.7.6) have been solubilized form whole green leaves of barley (Hordeum vulgare L.). Three major forms of the solubilized enzyme have been isolated by sonication in high ionic strength buffers, cation and anion exchange chromatography, and agarose gel permeation chromatography and designated I, II, and III. The enzyme fractions appear analogous to the Class I, II, and III ribonucleic acid polymerases defined in other eucaryotic systems. The ionic strength optima, amatoxin sensitivity, and relative activities with denatured calf thymus deoxyribonucleic acid were different for Class I, II, and III polymerases.

A simple, rapid, reproducible method …

Vector Preference Among Varieties Of Lycopersicon Peruvianum And L. Esculentum As Related To Curly Top Virus Resistance, Stanford A. Young

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Tests substantiating vector nonpreference as a factor in the ability of certain tomato varieties to escape curly top virus (CTV) infection were conducted and evaluated. Nonpreference is not an effective mode of resistance to CTV in tomatoes under field conditions since leafhoppers feed on and may infect plants before expressing a preference.

Preference of viruliferous leafhoppers was observed on plants of seven tomato varieties arranged both randomly and homogeneously in caged flats. Through observation of curly top symptom development, relative resistance due to vector nonpreference was calculated for each variety.

Up to 23 per cent of the fairly high resistance …

The Action Of Antibiotics And Antimetabolites On The Tobacco Mosaic Virus Infection Process In Bean Leaves, Virendra Nayyar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The action of 28 antibiotics and antimetabolites at varying concentrations was studied in coincidence with the bioassay of tobacco mosaic virus on detached bean leaves by using an ultrasonic method of inoculation developed by Lamborn, Cochran and Chidester.¹ All tested chemicals were classified, in regard to the virus infection process, as inhibitory or stimulatory and their optimal concentrations in the inoculum were determined. Of the 28 antibiotics and antimetabolites studied, eight were found to stimulate while twenty inhibited TMV infection in bean leaves. From the results of these experiments, an attempt was made to characterize the nature of the …

Investigations Of Unusual Curly Top Symptoms In Grafted Tomato Plants And Early Leafhopper Feeding Effects Upon Tomato Seedlings, Donald Eldon Gardner

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

To determine possible unusual effects of resistant plants upon symptom expression of curly top disease in susceptible tomato plants (Lycopersicon esculentum Mill.), tops of susceptible plants were grafted to lower stems and roots of resistant plants and inoculated. The resistant plants used were wild relatives of L. esculentum: L. peruvianum var. dentatum Dun. and L. peruvianum var. humifusum C. H. Mul. Reciprocal grafts, in which tops of dentatum plants were grafted to lower stems and roots of L. esculentum, were also made and inoculated.

External symptoms in the grafted plant tops were observed and compared with those of nongrafted, …

A Rapid Serological Bean Blight Test And Antibiotic Control Measures, Terry Dee Miller

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The detection and identification of bacterial pathogens in bean tissues can be accomplished with relative ease and certainty by utilizing antiserum prepared against specific bean pathogens. This test requires only fifteen minutes to complete, and a minimum amount of equipment. In addition to speed and ease, it eliminates the difficult process of isolating the bacterial pathogens from the many contaminants that will grow in nutrient culture techniques. The advantage of this technique is primarily based on the utilization of the bacterial population already present in the diseased plant tissues.

The effectiveness of this method has been demonstrated by diagnosing beans …

Overwintering Of Erwinia Amylovora Inside Living Host Tissue In Cache Valley, Utah, G. Doyle Morrill

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Experiments were conducted to see if Erwinia amylovora (Burrill) Winslow et al. overwinters inside living host tissue in Utah. Bacteria, collected from apple, pear, mountain ash, chokecherry and Pyracantha, were used in the experiment. Isolates taken from buds and inner bark plated on nutrient yeast dextrose agar, we re tested by serological and bacteriophage techniques. Those showing positive tests were then inoculated into Bartlett pear seedlings to test virulence.

Both virulent and avirulent isolates were isolated from each species of plant in the experiment. Pathogenic bacteria were isolated from diseased tissue near cankers, as well as from apparently healthy inner …

Effects Of Two Pathogenically Differing Isolates Of Verticillium Albo-Abrum On Tomato Growth, Leonidas Berry Camp

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A study was performed using isolates of Verticillium albo-atrum which were reported as varying in their pathogenicities to a susceptible and resistant tomato variety. Also included as objectives in this undertaking were cross-protection and effects of spore density in the inoculum on the development and severity of Verticillium wilt of tomatoes.

After retesting the strains which were reported as pathogenic variants, results suggested that reported variabilities were non-existent in most of the isolates and instead there were only two pathogenic type-categories: (a) strains pathogenic to both resistant and susceptible tomato varieties; and (b) strains pathogenic only to the susceptible variety. …

Factors Associated With The Penetration And Colonization Of Tomatoes By Verticillium Dahliae, Terry Dee Miller

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Experiments have demonstrated that Verticillium dahliae is capable of direct cortical penetration of roots and of subsequent distribution throughout plants of both resistant (Loran Blood) and susceptible (Meteor) varieties of tomato. Plants were inoculated by the root dip method and planted in sterile soil. After one week the fungus was isolated from the upper portions of both the susceptible and resistant varieties as indicated by growth petiole sections plated on PDA. The distribution of the fungus in the resistant plants was irregular, but in susceptible plants the fungus was isolated regularly from all petiole sections. In experiments using disposable growth …

Temperature And Inoculum Density As Factors Affecting The Pathogenicity Of Rhizoctonia Solani Kühn On Radish, Paul E. Moser

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effect of temperature and inoculum density on the incidence of disease on radish caused by Rhizoctonia solani Kühn was studied. The fungus attacks radish at one or more stages during host development and causes pre- and pose-emergence damping-off, root rot, and storage-organ decay. The isolate of the fungus used in the study was obtained from infected radishes grown in Salt Lake County, Utah.

To determine the effect of temperature on the pathogenicity of R. solani on radish, soil temperatures of 15, 20, 25, and 30 C were used. Varying inoculum densities of 1360, 816, 408, 136, and 0 grams …

A Survey Of Verticillium Albo-Atrum From Tomato Fields Of Northern Utah, Jean Redmond Musselman

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Verticillium wilt has long been a major disease of tomatoes in Utah. The disease was recognized long before the causal agent was known. In 1932, Dr. H. L. Blood was given the task of investigating a wilt disease that was causing heavy losses to Utah's tomato industry (5). The disease was thought to be caused by Fusarium oxysporum f. lycopersici (Sacc.) Snyder & Hansen. Through his investigations Dr. Blood found Verticillium albo-atrum Reinke and Berthold to be the cause of the disease. He began the laborious task of finding a resistant variety of tomato and transferring the resistance to commercial …

A Cytological Study Of Germinating Aeciospores In The Cronartium Coleosporioides Complex, John A. Christenson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Peridermium harknessii Moore, causal agent of western gall rust, is responsible for deformation, cull and death of pine. In the West it is most serious on lodgepole and ponderosa pines. Seedlings and mature trees may be seriously attacked (Peterson, 1960). Gall rust is easily recognized by its branch galls and trunk cankers. Interest in the disease has fluctuated, but it is considered important enough that government monies support research on the disease in both the United States and Canada.

Studies Of Peronspora Trifoliorum Debary Cause Of Downy Mildew Of Alfalfa, Sheldon B. Waite

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Downy mildew of alfalfa (caused by Peronospora trifoliorum d By) was found to be epidemic on susceptible varieties of alfalfa in northern Utah during 1965. The increase in the amount of downy mildew present was due to the more abundant rainfall and cooler than normal temperatures which prevailed during the summer months of 1965 (Environmental Science Services Administration, 1965). The author observed many of the highly susceptible varieties of alfalfa had 25-30 percent of their leaflets infected with the downy mildew fungus. Because of the epidemic developments of alfalfa downy mildew, an investigation was undertaken to explore the following questions …

Studies On The Relationship Of Polygalacturonase Inhibitors To Verticillium Wilt Resistance In Tomatoes, Robert Lee Sneed

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Early studies of the vascular wilts were directed toward understanding the wilting of susceptible varieties (19, 22, 23). Only in recent years have workers begun to study plant resistance to Fusarium and Verticillium wilts.

A Study Of The Development Of The Sexual Stage Of Rhytisma Punctatum (Pers.) Fries, Ching-Fei Chen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Speckled tar spot caused by Rhytisma punctatum (Persoon) Fries is often found on maples in many parts of the world (Holden, 1961; Koval', 1960; Saccardo, 1889). In Northern Utah it develops every year on leaves of Acer grandidentatum Nutt., and it is especially abundant at elevations above 6,000 feet, where often it is difficult to find even one uninfected leaf. The black speckled spots and the associated leaf coloring tend to add to the brilliance of the autumn colors normally found in the leaves of Bigtooth Maple.

Mechanical Transmission Of A Latent Virus From Apple To Herbaceous Plants, Ali Majid Jafri

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Recent work has shown that viruses are widely disseminated in commercial apple trees growing in this country (1, 14, 16, 17)—quite often one or more latent viruses are found in these plants. Usually latent viruses produce no symptoms, except in special indicator hosts. Latent viruses may cause severe injury when infected plants are grafted to a sensitive variety or rootstock. Actual damage caused by most of the apple viruses is not known but some of these definitely cause serious losses. Experimental plots at Utah State University were ruined by stem pitting virus infection. However, other latent viruses were also present …

Studies And Observations On Potato Powdery Mildew, Brent C. Palmer

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Within the past several years, powdery mildew disease has become an increasingly important problem to potato growers in the northern part of Utah. In some fields, reduction in yield due to powdery mildew has been estimated to be as high as 30 percent (Treshow and Cannon, 1961). The disease has been reported from many parts of the world. Other than in Utah, however, the only place where it has been considered to be of economic importance is Palestine. In that country, reduction in yield has been estimated to be as high as 20 percent (Palti and Moeller, 1946).

Studies On Flagging And Root And Butt Rot Of Subalpine Fir, Abies Lasiocarpa (Hook.) Nutt., David Lavar Nelson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Subalpine fir, Abies lasiocarpa (Hook.) Nutt., is a common climax dominant of the extensive spruce-fir forests of the subalpine zone of the Rocky Mountains from the southern Yukon Territory to the high mountains of New Mexico and Arizona (Society of American Foresters, 1954).

Infrared Spectroscopy As Applied To The Study Of Biochemical Changes Induced By Tobacco Mosaic Virus In Leaf Cells, Banavara Krishnappa Chandrasekhar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The biochemical reactions occurring during the early stages in the infection cycle of a plant virus are still unknown. Many studies involving bacteriophage and animal viruses that have been made in recent years have provided evidence of the nature of virus infection, but these have not been of much value in understanding the nature of plant viruses. Infrared spectroscopy applied to the study of viral infection processes by Chochran and his co-workers (1960, 1962) have given some clues about the nature of biochemical changes taking place in the leaf tissues as a result of infection with cucumber mosaic virus and …

Chemical Control Of Spoilage Of Dates, A. Razak Almandil

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Dates are typically a fruit of the subtropical arid regions of the world and are native to the valley of the Euphrates. According to Nixon and Crawford (1936), the earliest records in Iraq (those of the ancient Babylonians and Assyrians) show that their culture was established as early as 3000 B. C.

Basidiomycetes Of The Mount Dellenbaugh Region Of Mohave County, Arizona, Robert Burke Mccomb

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Mount Dellenbaugh is located on the Shivwits Plateau bordering the north rim of the Grand Canyon in Mohave County, Arizona. The elevation of the plateau in the Mount Dellenbaugh area is approximately 6,000 feet. The dominant species comprising the flora of this region are: Pinus ponderosa, Pinus edulis, Juniperus ostiosperma, Quercus gambelli, and Artemisia tredentata.

The Effect Of Certain Fluoride Sprays In The Production Of Soft Suture On Peaches, N. V. Narayanamoorthy

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Pollution of the atmosphere and its potential deleterious effects on health, industry, agriculture and natural resources are causing grave concern in many parts of the world. In the past century there has developed in the fields embraced by physical and biological sciences a considerable knowledge of theoretical and applied information, serving as a versatile tool in combating such problems. Air pollution problems seem to have gained much attention with the rapid development of various industries in major parts of the world. Rural and urban areas adjoining these industrial locales are confronted with the dangerous overall problems of air pollution. Evidently, …

Green Rot Of Apricot, Abdul Karim N. Alrayis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This disease, also called jacket rot of apricot, was first though to be similar to a disease caused by a fungus found in central California. The Utah disease was first noted in 1953, in the Henry Hall Chinese apricot orchard at North Ogden. It was not very severe in 1953, but in 1954 and 1955 it affected half of the crop. In 1956 the disease could not be found in the orchard. Infection occurred in young green fruit resulting in brown to black necrotic lesions which varied from 1/4 to 3/4 inches in diameter. Infected fruits usually dropped from the …

The Backcross Method In Breeding Tomatoes Resistant To Fusarium Wilt, Joseph L. Peterson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Many times the plant pathologist and plant breeder are confronted with a plant disease which requires the development of a resistant variety in a limited time. Any breeding program which requires selection from a large population during each segregating generation to insure the right genetic combination will, of course, lengthen the period which it will take to develop this resistant variety. The backcross method of plant breeding, in many cases, helps the plant pathologist and plant breeder develop resistant varieties containing characteristics similar to those of the desired parental type within a shorter period of time.

Red Raspberry Root Rot In Northern Utah, Robert L. Powelson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

During the last few years, red raspberry growers in Utah have been finding that plantings gradually lose vigor and are not profitable. In the largest raspberry growing area in Utah, Utah County, figures taken from the U.S. census from 1930 to 1950, show a decrease in acres of raspberries grown from 401 in 1930 to 190 in 1950 (2). In many instances this deterioration of raspberry plantings in Utah has not been definitely associated with known plant pathogenic fungi or virus infections. Neither can the expansion of suburbs account for this decrease. In certain cases it has been obvious that …