Plant Pathology Commons^™

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 …

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 …

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 …

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 …

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.

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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.

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 …

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 …

Further Studies On The Effect Of Environment On Potato Degeneration Diseases, R. W. Goss, George L. Peltier

Nebraska Agricultural Experiment Station: Historical Research Bulletins

The identification of potato degeneration diseases in the field is extremely difficult owing to the number of diseases now described, their manifestation on different varieties, the combination of several diseases on the same plant, and the further splitting up of these combinations into separate diseases. The influence of environmental factors in intensifying or inhibiting the symptoms of these diseases also increases the difficulty of diagnosis. In the present investigation the effect of environmental factors has been studied with the purpose of determining the limiting factor or factors in the masking of the symptoms, in the hopes of simplifying a complex …

Control Equipment For The Study Of The Relation Of Environment To Disease, George L. Peltier, R. W. Goss

Nebraska Agricultural Experiment Station: Historical Research Bulletins

The investigation of certain plant disease problems in Nebraska has necessitated the study of the relation of various environmental factors to these diseases. The control of these environmental factors in the greenhouse studies has been obtained by the use of previously described apparatus or their modification and adaptation, along with new methods which have been devised to meet the needs of these investigations. In view of the widespread interest in the subject of environmental control for experimental studies, it was deemed advisable to present briefly the methods now in use in this department in the hope that the information may …

Potato Wilt And Stem-End Rot Caused By Fusarium Eumartii, R. W. Goss

Nebraska Agricultural Experiment Station: Historical Research Bulletins

The present study was undertaken to obtain more information regarding the pathogenicity of Fusarium eumartii and to compare its action with F. oxysporum, in order to distinguish between and to determine the relative importance of the diseases produced by these two organisms. An effort was also made to explain the many negative results of isolation studies reported by various investigators, as well as the inconsistent results often reported in studies of the transmission of wilt by infected tubers. Investigations dealing with the effect of certain environmental conditions on the occurrence of the disease were also undertaken. All of the …

Effect Of Environment On Potato Degeneration Diseases, R. W. Goss

Nebraska Agricultural Experiment Station: Historical Research Bulletins

During recent years much of the investigational work on the degeneration diseases of the potato has been directed toward the separation and identification of a number of diseases formerly grouped under the general names of mosaic, leaf roll, and "running out". Extensive studies have also been made on methods of transmission, host range, overwintering and the identification of the evasive causal factor. Investigations of this type, however, have progressed slowly because of the necessity of developing new methods of research, because of the complexity of the problem, and because of the lack of knowledge regarding the causal factors. Meanwhile there …

A Study Of The Environmental Conditions Influencing The Development Of Stem Rust In The Absence Of An Alternate Host. Ii. Infection Studies With Puccinia Graminis Tritici Form Iii And Form Ix, George L. Peltier

Nebraska Agricultural Experiment Station: Historical Research Bulletins

Stakman and Levine have shown that Puccinia graminis tritici (Pers.) Erikss. and Henn. consists of a number of biologic forms, which can be determined by their action on different varieties of Triticum species. To date 37 such biologic forms have been identified by them through the parasitic action on 12 differential hosts chosen from a large number of varieties of Triticum species. To determine whether these biologic forms remain constant in their behavior under various environmental conditions, a detailed study of the host-parasite relation was undertaken with 2 of these forms. At the same time an opportunity was afforded to …

Seed Potato Investigations, H. O. Werner, R. F. Howard

Nebraska Agricultural Experiment Station: Historical Research Bulletins

The objects of the investigations reported in this bulletin were:

• To determine the condition of western Nebraska seed stock by the tuber unit method and by comparative trials in western Nebraska and various other points.
• To determine the effect of culture, place, disease, etc., upon seed value.
• To perfect methods of applying results to seed production in western Nebraska.

Relation Of Environment And Other Factors To Potato Wilt Caused By Fusarium Oxysporum, R. W. Goss

Nebraska Agricultural Experiment Station: Historical Research Bulletins

The present work was undertaken to determine the influence of some environmental factors on the infection and progress of the disease potato wilt. The work has not progressed to the point of determining the exact relation of each of these factors. However, the results thus far obtained are presented here in order to direct attention to the nature and distribution of the disease in relation to the environmental conditions under which certain types of infection take place.

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

Nebraska Agricultural Experiment Station: Historical Research Bulletins

No exact data are at hand regarding the influence of temperature and relative humidity on the viability of the urediniospores of stem rust under controlled conditions. 1. The influence of relative humidity on the viability of the urediniospores of Puccinia graminis tritici Form III is very pronounced and closely associated with temperature. 2. At high relative humidities, depending somewhat on the temperature, the percentage of germination is low and the period over which the spores are viable is very short. 3. The same relation exists at the low relative humidities except that it is not so pronounced and is more …

Corn Investigations, T. A. Kiesselbach

Nebraska Agricultural Experiment Station: Historical Research Bulletins

The purpose of the investigations reported in this bulletin has been primarily to determine some of the underlying principles involved in corn improvement. The work comprises a study of some of the physiological characteristics of the crop together with a comparison of various selection, breeding, and cultural practices in their relation to grain yield.

Fusarium Blight Of The Soy Bean And The Relation Of Various Factors To Infection, Richard O. Cromwell

Nebraska Agricultural Experiment Station: Historical Research Bulletins

An investigation was outlined (1) to determine the parasitism of Fusarium on soy bean, (2) to establish its relationship to Fusaria of the section Elegans in so far as a comparison of the cultural characters permitted, and (3) by means of cross- inoculations and field studies to determine the relationship of this disease of soy beans to the wilt disease of cowpeas (Vigna sinensis Hassk.) caused by Fusarium tracheiphilum Smith. The results of these investigations up to the close of the summer of 1916 have been reported. The studies were continued at the North Carolina Experiment Station until the …

Studies Of The Etiology And Control Of Blister Canker On Apple Trees, J. Ralph Cooper

Nebraska Agricultural Experiment Station: Historical Research Bulletins

The blister canker caused by Nummularia discreta Tul. is by far the most destructive disease of apple trees found in the United States. Serious damage due to this disease was first reported in Illinois in 1902. Since that time the disease has been reported to cause much damage in all apple-producing sections east of the Rocky Mountains. In Nebraska the disease is so prevalent that it is practically impossible to find an orchard free from it, and in many instances whole orchards have been destroyed thru its attacks. Because of the rapid dissemination and the destructive nature of blister canker, …

Spraying Experiments In Nebraska, J. Ralph Cooper

Nebraska Agricultural Experiment Station: Historical Research Bulletins

The more important questions which were considered during the three years covered by the present report were as follows: 1. How many summer sprays are required and when should they be applied? 2. What is the difference in efficiency between various brands of arsenate of lead? 3. What are the relative values of lime sulphur and Bordeaux as fungicides for spraying apples? 4. Is it possible to lessen or prevent Bordeaux injury and at the same time control fungous diseases? 5. Is it possible to interchange Bordeaux and lime sulphur in a spray schedule in such a manner as to …

A Physiological Study Of Two Strains Of Fusarium In Their Causal Relation To Tuber Rot And Wilt Of Potato, George K. Link

Nebraska Agricultural Experiment Station: Historical Research Bulletins

1. Fusarium tuberivorum Wilcox and Link is the same as Fusarium trichothecioides Woll. 2. Both Fusarium oxysporum and F. trichothecioides can produce both tuber rot and wilt of the potato plant. 3. The wilt is induced by destruction of the root system and by clogging of the xylem elements in the stem, and is, in mild cases, marked by such symptoms as discoloration of leaves, curling and rolling of leaves, and production of aerial tubers. 4. Under field and storage conditions Fusarium oxysporum is more probably responsible for wilt than is F. trichothecioides, and the latter more responsible for …

A Dry Rot Of The Irish Potato Tuber, E. Mead Wilcox, George K.K. Link, Venus W. Pool

Nebraska Agricultural Experiment Station: Historical Research Bulletins

The first specimens of the dry rot herein described were received by the department of Agricultural Botany during the winter of 1907-1908 from western Nebraska. A preliminary survey of the situation showed clearly the importance of this new rot, and an exhaustive investigation of the disease was outlined and has been continued to the present time. The present publication gives the results secured to date in our investigation of this disease.