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A History of Plant Pathology in Virginia: The Moore Era (7/1/1984-3/31/1997)
The Moore Era was the second longest since the Department of Plant Pathology and Physiology was established in September 1949. The Wingard Era lasted from September 1949 until October 1964, 15 years. Laurence D. Moore was appointed Interim Department Head on July 1, 1984, and Department Head on July 1, 1985. He served in this capacity until March 31, 1997, or nearly 13 years. Moore actually submitted his resignation as Head as of July 1996, but agreed to continue until a successor could assume the headship. K. K. Hatzios, a professor in the Department, was selected on December 20, 1996, and assumed responsibility on April 1, 1997, thus ending the Moore Era.
In the 13-year Moore Era, there were many changes in the faculty, in disciplines, physical plant, and technologies. Perhaps the most significant change was the introduction of the desktop computer which led to changes in faculty life-style, and resulted in a drastic reduction in secretarial positions. This introduction to the electronic era affected individuals differently. Some at first found it to be a toy or an impediment, and they foundered before adapting to it as a useful tool. Others quickly adapted to it, and almost immediately their activities were enhanced by its use. Certainly the computer provided a fabulously easy mode of communication which improved relations and cooperation among pathologists and other scientists world-wide. Availability of technology for instantaneous exchange of reports, manuscripts, and other scientific information should speed up progress and accomplishment. However, electronic communication may or may not provide historians with a long-time, accessible record analogous to a "paper trail." How much of history will be preserved if documents are not printed out?
For many years, molecular biology was confined to research with bacteria and viruses and their interactions. While teaching Genetics of Host-Parasite Interactions, I bemoaned to my students that very little progress was made in applying molecular biology to plant pathology; especially in the area of host resistance to pathogens. In retrospect, plant pathologists and plant breeders were poorly trained in biotechnology. Until a generation trained in biotechnology began to utilize host-pathogen systems as research models, little progress could be expected. At V.P.I. & S.U., molecular biology was thrust upon us by administrators. The PPWS department was picked by the administration to house two molecular biologists, their research, and teaching. While George Lacy was the first in the Department that was trained in molecular biology (=biotech), his research was a furtherance of biotech in bacteria; he did not apply biotech to higher plants. Sue Tolin, being a virologist, had to think molecular about viruses, but neither did she apply biotech to higher plants. Dean of The College of Agriculture and Life Science (CALS), James R. Nichols, apparently forced the hand by requiring that vacancies in certain departments be filled by hiring persons explicitly trained in biotechnology. In PPWS, Carole Cramer was the first such candidate. Appointed on September 1, 1986, she made initial efforts to apply biotech to plant pathology. In addition, M. A. Saghai-Maroof was appointed to a similar position in the Department of Crop and Soil Environmental Sciences (formerly the Agronomy Department). He worked initially to locate genes conditioning gray leafspot resistance in maize. Elizabeth Grabau was also hired into PPWS as a member of the biotech group in 1990, but her initial work did not relate to plant pathology. The department's brick laboratory-office building on Glade Road was upgraded in 1987 to provide laboratory and office space for Cramer and her associates. Thus, Cramer joined Sue Tolin, George Lacy, and Kriton Hatzios, already housed there, and the building was christened The Plant Molecular Biology Building.
Coincident with the hiring of Cramer, and perhaps an impetus to her accepting an appointment in PPWS, was the acquisition of equipment and microbial cultures from Allied Chemical Corporation valued at over $1,300,000. It seems that management of Allied had decided to divest its biotechnology research and would have useful modern equipment to discard. George Lacy had been on the advisory panel for Allied's biotech research; he apprised Gary Hooper, Vice-Provost for Research, of the situation. Hooper, Moore's predecessor, entered into negotiations with Allied to have the equipment and cultures donated to V.P.I. & S.U. Much of the donated equipment was designated for Cramer's laboratory in the refurbished Glade Road building. Charles Hagedorn, a leader in Allied's biotech research, was offered a joint appointment with PPWS and Crop and Soil Environmental Sciences (formerly Agronomy). Subsequently, Hagedorn made significant contributions to plant pathology and Virginia agriculture. Although this development happened during Moore's headship, the actual dealings were conducted by higher administrations. Nevertheless, it was a significant event of the Moore Era.
A new laboratory building, the Fralin Biotechnology Center, provided space for Cramer and Grabau in late 1995. A cadre of graduate students and research associates soon joined them.
When Cramer moved to Fralin Hall, Ruth Alscher was moved to Cramer's emptied space. There, Alscher would have modern space and would be closer to the air pollution research facility with which she was heavily involved.
An event occurred in late 1986 in which PPWS was no way involved, but later in the Moore Era would be of great benefit to the College of Agriculture and Life Sciences. The University swapped the Horticulture Farm near Christiansburg and two other small parcels of land for a 1,900 acre farm at Whitethorne in western Montgomery County. The PPWS department would benefit by having available a considerable acreage of uniform plot land. Through the Moore Era, Erik Stromberg and Herman Warren were the principle beneficiaries in PPWS (see the section on Cereals-Corn). Ironically, the land-swap deal caused the head of the Horticulture Department to resign and may have contributed to the downfall of University President W. E. Lavery. The benefit to the University was overlooked by influential people and organizations who thought loss of their beloved Horticulture Farm was the result of underhanded dealing. They did not recognize that their farm had become obsolete; they were miffled because they had not been included in the negotiations.
A plan involving four Virginia Agricultural Experiment Station member colleges known as 'The Plan to Serve Virginia Agriculture, Human and Natural Resources" was completed in 1995 and implemented soon, thereafter. This plan allocated 20 faculty and 15 staff positions to PPWS on campus; ten were in plant pathology, five in plant physiology, and five in weed science. In addition, two positions, one in plant pathology and one in plant physiology, were located to Eastern Shore (Painter), Hampton Roads (Virginia Beach), Tidewater (Suffolk), and Winchester Agriculture Research and Educator Centers, and a plant pathology position was allocated to the Southern Piedmont station (Blackstone). Thus, 29 faculty positions were allocated to PPWS; slightly less than the number in the Couch-Foy-Hooper Eras. When the Moore Era ended, the Department had 17 plant pathologists, 5 plant physiologists, and 5 weed scientists.
Moore had reinstated the Annual Departmental Report in 1987, and saw to publication of two issues of the Physiopath, the departmental newsletter.
The L.I. Miller Scholarship for graduate education was established in memory of Professor Miller who died unexpectedly on March 8, 1996.
In 1988, the University changed from the quarter to the semester system of instruction. This required revision of courses and kept catalogue listings and faculty in a state of flux for several years. Details will be described in the instruction section of the Moore Era.
Changing times resulted in cross-departmental programs that brought the PPWS faculty into greater participation with faculty from other departments in other colleges. PPWS faculty also became involved in teaching biology and agricultural technology courses. It will be difficult for me to portray these changes accurately.
In 1985, the Eastern Shore Agricultural Research and Education Center became an integral part of the Virginia Agricultural Experiment Station. Thereafter, R. E. Baldwin, Plant Pathologist, and H. P. Wilson, Weed Scientist, were considered members of the PPWS faculty.
Some other noteworthy events of the Moore Era were:
Completion of a new pesticides storage building.
Renovation of greenhouses.
Third (Nov. 5 - 8, 1984) and Fourth (Dec. 1 - 4, 1992) Departmental Comprehensive Reviews. Recommendations of the two review panels relative to plant pathology are given below.
George Lacy and his co-workers, Verlyn Stromberg, Laboratory Specialist, and graduate students D. P. Roberts and Caitilyn Allen, were the first at V.P.I. & S.U. to clone DNA molecules.
The first patent relative to plant pathology issued to V.P.I. & S.U. faculty was to M. A. Saghai-Maroof, G. K. Rufener, II, Erik L. Stromberg, R. P. Mowers, A. J. Balducchi; Gray Leafspot Resistant Corn and the Production Thereof (U.S. Patent No. 5, 574, 310. Nov. 12, 1996.).
Withdrawal of USDA peanut research programs at Suffolk occurred abruptly in 1994. From 1955 to November 1994, K. H. Garren and D. M. Porter, USDA plant pathologists, held staggered appointments there.
The third and fourth Cooperative State Research, Education, and Extension Service (CSREES) comprehensive reviews of the Department resulted in the following recommendations relative to plant pathology:
1984 - "Capitalize on current strengths and projected faculty changes to provide leadership in developing integrated plant health management and in focusing on the biotechnology initiative of the University. .....Develop new courses in weed science, molecular biology, and electron microscopy. ..... Train more county personnel in clinical diagnostic skills. .....Give more attention to conservation tillage development to be better prepared to handle potential problems." Among the panelists were two plant pathologists, Kenneth R. Barker from North Carolina State University and Wiley N. Garrett from the University of Georgia.
1992 - "To help ensure the future welfare of the Department, every attempt must be made to update the skills of it's technical staff. The development of a university-wide "plant sciences" major should be considered in conjunction with the botanists of the Biology Department and other Departments in CALS (College of Agriculture and Life Sciences) having plant science faculty. CALS Departments should give serious consideration in requiring appropriate courses in Plant Pathology, Physiology, and Weed Science as part of their under-graduate curriculum requirements. Content of graduate courses should be reviewed thoroughly and appropriate changes should be made, if necessary. ..... Greater team effort on interdisciplinary approaches to plant health should be explored. More cultural management investigations were suggested in addition to chemical approaches for pest problems. ..... Greater efficiency in plant disease diagnostics and electronic transmission of results are encouraged." Among the panelists were plant pathologists Clauzell Stevens, Tuskegee University, and Anne K. Vidaver, University of Nebraska.
During the Moore Era, many of the recommendations were implemented, but budget cuts necessitating personnel cuts made them infeasible. Cooperation from other departments and colleges could not be forced, yet progress was evident. Contrary to the recommendation that instruction in plant pathology in undergraduate curricula be increased, there is pressure from some departments to reduce it. Many recommendations were directed toward administrators and were beyond the realm of PPWS faculty attention.
When Moore was appointed Interim Department head on July 1, 1984, the faculty consisted of the following:
Professors–their primary disciplines are noted:
S. W. Bingham, Weed Science, turf.
H. B. Couch, Plant Pathology, turf.
C. R. Drake, Plant Pathology, fruit.
C. L. Foy, Weed Science, herbicidal action.
R. L. Grayson, Plant Pathology, Director of Electron Microscope Laboratory.
G. J. Griffin, Plant Pathology, forests and soil microbiology.
L. D. Moore, Plant Pathology, disease physiology.
C. W. Roane, Plant Pathology, field crops.
R. J. Stipes, Plant Pathology, landscape trees.
Sue A. Tolin, Plant Pathology, virology.
W. H. Wills, Plant Pathology, ornamental plants.
Associate Professors -
S. A. Alexander, Plant Pathology, forests, Christmas trees.
M. G. Hale, Plant Physiology, plant stress.
K. Hatzios, Plant Physiology, weed science.
G. H. Lacy, Plant Pathology, phytobacteriology.
R. C. Lambe, Plant Pathology, Extension, ornamental plants, nursery crops.
D. A. Orcutt, Plant Physiology, instruction, plant stress.
P. M. Phipps, Plant Pathology, peanut.
K. S. Yoder, Plant Pathology, fruit.
Assistant Professors -
D. E. Babineau, Plant Pathology, Extension, cereals, soybeans.
A. B. A. M. Baudoin, Plant Pathology, instruction.
B. I. Chevone, Plant Pathology, air pollution.
J. F. Derr, Weed Science, Extension, ornamental and vegetable crops.
Alma P. Elliott, Plant Pathology, nematology.
E. S. Hagood, Jr., Weed Science, Extension.
D. A. Komm, Plant Pathology, Extension, tobacco.
J. J. Reilly, Plant Pathology, tobacco.
E. L. Stromberg, Plant Pathology, cereals and soybean.
M. J. Weaver, Pesticides Coordinator.
W. E. Winner, Plant Physiology, air pollution.
Adjunct Professors -
J. R. Elkins, Concord College, W. Va., chestnut restoration.
D. M. Porter, Plant Pathology, U.S.D.A., Suffolk, peanut.
Martha K. Roane, Plant Pathology and Taxonomy, Endothia, Ericaceae.
Changes in faculty during the Moore Era, including new appointments, promotions, resignations, and retirements: New appointments - The Virginia Truck and Ornamental Research and Education Centers in Virginia Beach and Accomack County became a part of the Virginia Agricultural Experiment Station in 1985. As a result, R. E. Baldwin and H. P. Wilson became professors in the department. In chronological order, those appointed to the faculty 1984 - 1995 as Assistant Professors unless otherwise noted included:
C. S. Johnson, Plant Pathology, tobacco, September 1, 1985.
J. D. Eisenback, Plant Pathology, nematology, September 1, 1985.
Carole L. Cramer, Plant Physiology, September 1, 1986.
Charles Hagedorn, Professor, Microbiology, 1986; Hagedorn was appointed 50% in Crop and Soil Environment Sciences and 50% in PPWS.
H. L. Warren, Plant Pathology, Commonwealth Visiting Professor, December 1, 1987. Appointed to faculty May 1, 1989.
Ruth Alscher, Associate Professor, Plant Physiology, 1988.
Charles Swann, Professor of Weed Science, 1988.
Elizabeth A. Grabau, Plant Physiology, 1990.
J. H. Westwood, Plant Physiology, 1994.
Alma P. Elliott, November 30, 1984.
J. J. Reilly, December 31, 1984.
D. A. Komm, January 31, 1985.
D. E. Babineau, February 1, 1985.
W. E. Winner, 1987.
M. G. Hale, April 30, 1985.
C. W. Roane, August 30, 1986.
R. C. Lambe, May 31, 1988.
C. R. Drake, September 30, 1989.
W. H. Wills, September 30, 1990.
J. L. Derr, July 1, 1988; transferred to the Hampton Roads Agricultural Research and Education Center, Virginia Beach.
M. J. Weaver, July 1, 1991; transferred to Chemical Pesticides Unit.
S. A. Alexander, August 1, 1995; transferred to Eastern Shore Research and Education Center to fill the position from which R. E. Baldwin would retire.
To Associate Professor -
1986 - B. I. Chevone, E. S. Hagood, Jr.
1987 - A.B.A.M. Baudoin, E. S. Stromberg.
1990 - Carole L. Cramer, J. F. Derr, J. D. Eisenback.
1991 - C. S. Johnson.
1996 - Elizabeth A. Grabau.
To Professor -
1988 - K. Hatzios, G. H. Lacy.
1989 - P. M. Phipps.
1991 - E. S. Hagood, Jr., D. M. Orcutt.
1994 - J. D. Eisenback, E. L. Stromberg.
All promotions were effective on July 1.
Mary Ann Hansen had been appointed Laboratory Specialist C in 1984, was named Instructor in 1993; she was supervisor of the Plant Disease Clinic for PPWS.
Jodi A. Carlson was appointed Research Associate August 1, 1991 to conduct research, extension, and instruction programs formerly conducted by S. A. Alexander. She received the Ph. D. Degree in May 1994 and resigned soon thereafter.
In 1989, the Department celebrated its 40th anniversary by hosting the annual meeting of the American Phytopathological Society in Richmond, Virginia. Erik Stromberg and Larry Moore served as Co-Chairmen of the Local Arrangements Committee and co-hosts. Several other members of the Department served on committees for the meeting (see section on Service to Societies.). Following this event, the Department held an open house in Blacksburg. Four original recipients of masters degrees, Mary Comfort McBryde Miller (1933), R. Spencer Mullin (1936), and Lawrence I. Miller (1938), and Curtis W. Roane (1944), attended the open house and banquet. Charles R. Drake was an honored guest celebrating his retirement after 33 years on the faculty. Roane outlined a history of the Department, 1888 - 1989.
The basic mission in the teaching program of the Department has remained unchanged since the Couch Era. For undergraduate students, the Department has no undergraduate curriculum but provides service courses for students in Agronomy (= Crop and Soil Environmental Sciences), Forestry, and Horticulture. The undergraduate courses Plant Pathology, Pesticide Usage, Pest and Stress Management of Trees, and Plant Responses to Air Pollutants are sometimes included in programs of study for graduate students. Several graduate courses are taken by students in the above named departments. Until 1992, all instruction was conducted on the Blacksburg campus. In that year, an M. S. Program Horticulture/Plant Sciences was established at the Hampton Roads Agricultural Research and Extension Center in Virginia Beach. Courses in plant pathology are included in the program.
In 1995, plant pathology faculty began teaching in the Biological Sciences Initiative (BSI) which facilitates cross-departmental teaching assignments and provides the best possible learning experience to life science students. Plant pathologists assumed teaching responsibility for General Biology, Principles of Biology, Introductory Genetics, Soil Microbiology, and Soil Microbiology Laboratory. They also taught and advised students in the two-year Agricultural Technology Program offered by the College of Agriculture and Life Sciences, namely, Plant Agriculture, Pest Management, Agriculture Chemistry Principles, and Diseases of Turfgrasses. Thus, inter-disciplinary teaching in the Moore Era became somewhat on par with inter-disciplinary research which was long practiced by plant pathology faculty.
Some faculty contributions become walled off by titles and administrative hierarchies. Randy (R. L.) Grayson fell into this category. He had been hired as Professor of Plant Pathology and Director of the Electron Microscopy Laboratory during the Hooper Era. He held that position until 1997, when he was appointed Co-Director of the Minority Academic Opportunities Program (MAOP). Thereupon, his directorship at the Electron Microscopy Laboratory ended. During his tenure with the laboratory, he taught Electron Microscopy to 42 students during five academic terms. This is hidden under the title of Special Study. Several students majoring in Plant Pathology took the course and utilized the scope in their thesis/dissertation research.
During the Moore Era, the University changed its academic year from a quarter system (fall, winter, spring) to a semester system (fall, spring). Two terms were offered each summer under both systems. The change from quarters to semesters necessitated a reduction in the number of courses that could be offered, or a reduction in credit hours for courses. The course offerings under each system reflect changes. However, there was considerable rearrangement as a result of trial and error. In the end, several courses were jointly taught by two or more instructors. Team teaching was unsavory to most caught up in it.
In order to show the transition from the quarter to the semester system, the courses offered under each system are listed below.
Plant Pathology courses listed in the catalogs at the beginning of the Moore Era:
2960 Field Study - variable credits.
3010 Plant Pathology - 3H, 3C, II.
3020 Plant Pathology Laboratory - 3L, 1C, II.
4010 Plant Responses to Air Pollutants - 3H, 3C, I.
4270 Forest Pathology - 3H, 3L, 4C, II.
4311 - 4312 Integrated Plant Pest Management - 3H, 3C, II, 9L, 3C, III.
4860 Virology - 3H, 3C.
4960 Field Study
4970 Independent Study - variable credits.
4980 Special Study - variable credits.
4990 Undergraduate Research - variable credits.
5020 Principles of Plant Disease Control - 3H, 3C, II..
5030 Plant Parasitic Nematodes - 1H, 6L, 3C, II, alt.
5040 Plant Virology - 3H, 3L, 4C, II, alt.
5090 Genetics of Host - Parasite Interactions - 3H, 3C, II, alt.
5111 Seminar - 1H, 1C, I.
5120 Concepts and Practices of Pesticide Application - 2H, 3L, 3C, III.
5150 Diseases of Field Crops - 3H, 3L, 4C, I.
5170 Epidemiology of Plant Diseases - 3H, 3L, 4C, II.
5221 Clinical Plant Pathology I - 6L, 2C, II.
5222 Clinical Plant Pathology II - 6L, 2C, III.
5900 Project and Report - 1-3C, any qtr.
5970 Independent Study - variable credits.
5980 Special Study - variable credits.
5990 Research and Thesis - variable credits.
6020 Principles of Plant Disease Development - 3H, 3C, I, alt.
6040 Physiology of Pathogenesis - 3H, 3L, 4C, III.
7990 Research and Dissertation - variable credits.
All courses above were offered under the quarter system. Roman numerals I, II, III at the end of each line refer to fall, winter, and spring quarters. The courses listed below were offered under the semester system. Roman numerals I, II, II there refer to fall, spring, and summer sessions.
Plant Pathology courses listed in the catalogs at the end of the Moore Era:
2964 Field Study - variable credits.
2984 Special Study - variable credits.
3104 Plant Pathology - 3H, 3L, 4C, I. 4224 Integrated Pest Management - 2H, 3L, 3C, I.
4264 Pesticide Usage - 2H, 3L, 3C, II.
4524 Pest and Stress Management of Trees - 2H, 3L, 3C, II.
4554 Plant Responses to Air Pollution - 1H, 1C, II.
4964 Field Study - variable credits.
4974 Independent Study - variable credits.
4984 Special Study - variable credits.
4994 Undergraduate Research - variable credits.
5004 Seminar - 1H, 1C, I, II.
5014 Plant Disease Agents: I. Fungi and Prokaryotes - 3H, 6L, 5C, I, alt.
5024 II. Viruses and Nematodes - 3H, 6L, 5C, II, alt.
5034 Clinic and Field Experience - 3L, 1C, I.
5204 Principles of Plant Disease Management - 3H, 3C, I.
5214 Diseases of Crop Plants - 3L, 1C, I.
5404 Genetic and Epidemiological Principles of Plant Pathology - 3H, 3L, 4C, II, alt.
5454 Plant Disease Physiology and Development - 3H, 3C, I, alt.
5894 Final Exam (Non-thesis) - I, II, III.
5904 Project and Report - variable credits.
5974 Independent Study - variable credits.
5984 Special Study - variable credits
5994 Research and Thesis - variable credits.
6004 Advanced Topics in Plant Pathology, Physiology, and Weed Science - variable credits.
6654 Topics in Virology - 3H, 3C, II, alt.
7994 Research and Dissertation - variable credits.
Other than renumbering and changes in hours and credits, some changes can be noted. Plant Pathology and Plant Pathology Laboratory (3010, 3020) were combined in the semester system (3104). Concepts and Practices of Pesticide Application (5120) was changed to undergraduate level as Pesticide Usage (4264). Forest Pathology (4270) was changed to Pest and Stress Management of Trees (4524); it included forest insects. Virology (4680) in the quarter system was cross-listed as a Biology course and was dropped from PPWS in the semester system. A new semester course, Plant Disease Agents (5014), included the study of Fungi and Prokaryotes, and in (5024) the study of Viruses (originally Plant Virology 5040), and Nematodes (originally Plant Parasitic Nematodes, 5030). Principles of Plant Disease Control (5020) became Principles of Plant Disease Management (5204).
Genetics of Host-Parasite Interactions (5090) and Epidemiology of Plant Diseases (5170) were combined into Genetic and Epidemiological Principles of Plant Pathology (5404). Clinical Plant Pathology (5221, 5222) was reduced to Clinic and Field Experience (5034). Diseases of Field Crops (5150) was broadened to Diseases of Crop Plants (5214). Principles of Plant Disease Development (6020) and Physiology of Plant Disease (6040) were combined into Plant Disease Physiology and Development (5454).
New listings included Final Exam, Non-thesis (5894), Advanced Topics in Plant Pathology, Physiology, and Weed Science (6004), and Topics in Virology (6654).
Several of the 5000 level courses were taught by committee (team-taught), namely, 5014, 5024, 5204, 5214, 5404, and 5454. Some combinations were undesirable both to students and faculty. For example, students in Crop Science may wish to have Genetics but not Epidemiology (5404), others might want Nematology but not Virology, or vice versa (5024), or Fungi and not Prokaryotes, or vice versa (5014). In team teaching, a student might excel under one instructor and flub under another. A compromised grade would not reveal a student's interests and aptitudes. In a later era, the system was changed so one could enroll for only the subject matter in which one was interested.
Students earning advanced degrees during the Moore Era are listed below. Those completing degrees in 1984 may have done so either in the Hooper or Moore Era. Some of their theses/dissertations may be discussed in the text on various crops or subjects that follow.
Year Author and Title Advisor 1984 Achwanya, Oliver Stafford. Effect of ozone, sulfur dioxide and alpha and delta races of Colletotrichum lindemuthianum (Sacc. & Magn.) Bri. And Cav. On bean Phaseolus vulgaris L. Ph.D. Moore 1984 Grant, Carrol Earl. Interactions of a tobacco cyst nematode and the black shank fungus with flue-cured tobacco. Ph.D. Reilly 1984 Hsia, Amos C. Y. Studies on host-parasite interactions of plant-parasitic nematodes in strawberry fields of Virginia. M.S. Elliott 1984 Kularatine, W. W. P. Saranananda. Effects of root media and control agents on propagule formations and survival of Phytophthora cinnamomi Rands and root rot of azalea caused by Phytophthora cinnamomi. M.S. Wills 1984 Niles, Robert Kenneth. Extraction procedures and population dynamics of plant-parasitic nematodes associated with non-bearing apple. M.S. Elliott 1984 Schmidt, Peter Raymond. Influence of non-oomycete active systemic fungicides on the severity of Pythium blight of bentgrass. M.S. Couch 1985 Agrizonis, Nester Bedardo. M.S. Non-thesis Alexander 1985 Horner, Elliott W. Etiologic studies of Verticicladiella procera Kendr in pine Christmas trees. Ph.D. Alexander 1985 Lewis, Katherine Joann. Studies on the spread of Verticicladiella procera by soil-borne and insect-borne propagules. M.S. Alexander 1985 Micales, Jessie Ann. The chemotaxonomy of the fungal genus Endothia Fr. Ph.D. Stipes 1985 Mojdehi, Hamidreza. Head scab of wheat. M.S., Non-thesis. Stromberg 1985 Roberts, Daniel Paul. Molecular mechanisms of pathogenesis incited by Erwinia carotovora subsp. carotovora. Ph.D. Lacy 1985 Specht, Laurence Paul. Inoculum densities of Thielaviopsis basicola in tobacco fields in Virginia, and the relationship of inoculum density to the severity of black root rot and growth of tobacco. Ph.D. Griffin 1985 Tuskan, Robert G. Comparison of nucleoproteins and nucleic acids of five isolates of tomato ringspot virus. M.S. Tolin 1985 Wickramabaskaran, Kandasam. Genetics of reaction to peanut mottle virus in four soybean cultivars. M.S., Non-thesis. Roane 1986 Brenneman, Timothy Banner. Sensitivity and resistance of Sclerotinia minor to fungicides for control of Sclerotinia of peanut. Ph.D. Phipps/Stipes 1986 Overton, Santford Vance. Physiological and ultrastructural effects of sterol-inhibiting fungicides on apple leaves and the scab fungus. Ph.D. Moore 1986 Rechcigl, Nancy Ann. Ultrastructural cytology of peanut infected with peanut stripe virus. M.S. Hooper/Tolin 1986 Tomimatsu, Gail S. Quantitative investigations of infection colonization of peanut roots by Cylindrocladium crotalariae. Ph.D. Griffin 1987 Allen, Caitilyn. Evolution of a gene for pathogenicity: Endopectate lyase. Ph.D. Lacy 1987 Farias, Graciella M. Quantitative investigations of Fusarium oxysporum and F. solani colonization and rot of Glycine max cv. Essex seedlings. M.S. Griffin 1987 Gates, Melinda Mulesky. Biological control studies ofWills Phytophthora parasitica root rot of boxwood using multiple antagonists. M.S. 1987 Gunyuzlu, Paul L. The nucleotide sequence of the 3' terminus of soybean mosaic virus. M.S. Tolin 1987 Jewell, Elspeth Lea. Correlation of early leafspot disease in peanut with a weather-dependent infection index. M.S. Phipps/Stromberg 1987 Reed, Karen Kynne. The influence of meteorological events and cultural practices on Sclerotinia crown and stem rot of alfalfa, caused by Sclerotinia trifoliorum. M.S. Stromberg 1988 Pooranampillai, Christina D. Evaluation of resistance to crown and stem rot caused by Sclerotinia trifoliorum. M.S. Stromberg 1989 Botha, Amanda Scheffler. The assessment of air pollution impacts on plants in South Africa. Ph.D. Moore 1989 Donahue, Patrick J. The inheritance of reaction to gray leaf spot and maize dwarf mosaic virus in maize and their association with physiological traits. Ph.D. Stromberg 1989 Mayes, Mary Sue. An ultrastructural and immunocytochemical study of the wheat soil-borne mosaic virus-Polymyxa graminis relationship. M.S. Grayson 1989 Reaver, Diane M. The effects of foliar applications of seaweed extracts on plant growth and pest resistance. M.S. Baudoin/Luma 1989 Smith, Brian Donald. The influence of high temperature stress and herbicides on susceptibility of creeping bentgrass (Agrostis palustris) to Curvularia lunata. M.S. Couch 1990 Johnson, David Alan. Infection and development of Ustilago syntherismae in Digitaria ciliaris. M.S. Baudoin 1990 Kyostio, Sirkka R. M. Erwinia carotovora extracellular proteases: Characterization and role in soft rot. Ph.D. Lacy 1990 Smith, Frisby Davis "Tad". Evaluation of fungicide resistance in Sclerontinia minor and strategies for chemical control of Sclerotinia blight in peanut, Ph.D. Phipps/Stipes 1990 Yang, Zenbiao. Gene regulation in a pathogen-plant interaction: Erwinia versus potato tubers. Ph.D. Lacy/Cramer 1991 Choi, Chang, Won. Soybean mosaic virus-soybean interactions: Molecular, biochemical, physiological and immunological analysis of resistance responses of soybean to soybean mosaic virus. Ph.D. Tolin 1991 Cu, Ramon M. Development and evaluation of a computerized leafspot advisory program for effective use of cultivar resistance, fungicide, and spray adjuvant to control early leafspot of peanut. Ph.D. Phipps/Stipes 1991 Nevill, Ralph John Leslie. The association and transmission of Leptographium procerum (Kender.) Wing., by root feeding insects in Christmas tree plantations. Ph.D. Alexander 1991 Scamack, Anita Marie. Apple Powdery mildew: Literature and research overview. M.S., Non-thesis. Yoder/Stipes 1992 Carter, Michele R. Gray leafspot of corn: Yield loss evaluation of germplasm for resistance. M.S. Stromberg 1992 Farias, Graciella M. Roles of tannase and hydrolyzable tannins in chestnut blight. Ph.D. Griffin 1992 Martinez, Natalia. Relationships among spreader-sticker application, blossom cap retention, berry scarring thrip populations, and botrytis bunch rot in 'Chardonnay' grapes and a survey of pesticides use and pest severity in Virginia vineyards in 1990 and 1991. M.S. Baudoin/Weaver 1992 Mota, Manuel M. Morphological characterization of tobacco cyst nematode complex, Globodera tabacum sspp. Ph.D. Eisenback 1992 Srinivasan, Indira. Isolation and detection of bean yellow mosaic, clover yellow vein and peanut stunt viruses from Trifolium spp. M.S. Tolin 1993 Guevara, Gonzalo G. Biological studies of shiitake logs and associated mycoflora in the Virginia highlands. M.S. Stipes 1993 Traut, Eduardo J. Bipolaris zeicola: physiological races morphology and resistance on maize. (Zea mays L.). Ph.D. Warren 1994 Carlson, Jodi Ann. Procerum root disease physiology and disease interaction with ozone. Ph.D. Alexander 1994 Crozier, James Brooks. Abiotic stressors in the dogwood anthracnose complex. M.S. Stipes 1994 Gera, Tarun. Tracking soybean mosaic virus movement in soybean by leaf imprint immunoassay. M.S. Tolin 1994 Zimmerman, Kris K. Evaluation of selected bacterial strains for control of dollar spot on creeping bentgrass and brown patch on tall fescue. M.S. Hagedorn 1995 Dorrance, Anne E. Inheritance of resistance to diplodia ear rot and an assessment of the genetic variability of Stenocarpella maydis through isozyme analysis. Ph.D. Warren 1995 Mulesky, Melinda Anne. Rhizosphere competence, antibiotic and siderophore biosynthesis in Pseudomonas chlororaphis: implications for the biological control of cotton seeding disease pathogens. Ph.D. Hagedorn 1996 Wang, Jia. Characterizing resistance in flue-cured tobacco to Globodera solanacearum tabacum. Ph.D. Johnson/Eisenback 1997 Flora, Jonathan P. The effect of temperature on the durabilityTolin of resistance of soybean to soybean mosaic virus. M.S. 1997 Kilic, Ozlem. Effect on dsRNA-contining and dsRNA-freeGriffin hypovirulent isolates of Fusarium oxysporum on severity of fusarium seedling disease of Essex soybean. M.S. 1997 McBane, Scott J. Algae control in bentgrass (Agrostis palustris) with DC5772® and ProfileTM. M.S., Non-thesis Couch 1997 Qusus, Saba J. Molecular studies on soybean mosaic virus- soybean interactions. Ph.D. Tolin 1997 Robbins, Nancy E. Spread of hypovirulent strains of Cryphonectria parasitica among American chestnut trees at Lesesne State Forest. M.S. Griffin
Research in fruit pathology was conducted both at Blacksburg and Winchester during the Moore Era. At Blacksburg, Charles R. Drake investigated diseases of apple, peach, and nectarine until his retirement on September 30, 1989. No one was appointed to replace him, and tree fruit pathology at Blacksburg died with his retirement. Thereupon, Keith S. Yoder at Winchester assumed responsibility for tree fruit pathology in the entire state. Anton Baudoin and Sue Tolin of Blacksburg developed some special programs on grape pathology. Extension programs in fruit pathology which were jointly executed by Drake and Yoder until 1989 were managed only by Yoder, thereafter.
For years, research and extension in fruit pathology have been highly integrated. In fact, the end-point of most research was to provide growers with the latest pesticide advisories via extension publications. That Drake and Yoder were on similar tracks may be ascertained by comparing their statements in the Department of Plant Pathology and Weed Science Annual Report of 1989. The first two statements are in regard to extension programs; the third is for research:
"TREE AND SMALL FRUITS DISEASES - Delineate the nature of diseases that attack tree and small fruits, work out practical, economical and safe methods for their control and to educate the fruit grower clientele of findings through effective media that they fully understand; thus, help to improve their profits. Provide Virginia's fruit growers with the latest information on pest management and control through timely, well-planned publications, orchard demonstrations and practical non-credit schools. Educate growers on the relationship of maximum net profit ratio and its dependency on the percent of US Extra Fancy pack-out fruit/acre. Advise growers of changes concerning fruit pesticide regulations by the Environmental Protection Agency that would influence their production. Alert growers to potential troublesome diseases that can be introduced into their operation on young trees or propagation materials." (C. R. Drake)
"MANAGEMENT OF TREE FRUIT DISEASE - Provides the Virginia fruit industry with economical disease management recommendations necessary to maintain production; to advise growers of changes in fruit pesticide regulations that affect their operations; to alert growers to unusual disease conditions or problems that can be avoided by prompt precautionary measures." (K. S. Yoder)
"BIOLOGY OF PATHOGENIC ORGANISMS RELATED TO FRUIT TREE DISEASES - Investigation of the biology of pathogenic organisms as related to fruit tree diseases and the search for effective and economical control measures for the diseases affecting the fruit industry in Virginia include: 1) improving the prediction of disease outbreaks, 2) developing an integrated approach to reduce problems affecting tree longevity, 3) comparing effectiveness and safety of experimental and standard disease control chemicals, including disease control spectrum and fruit finish effects, to provide data for registration or re-registration of useful materials, 4) determining ways to optimize fungicide performance, 5) developing control programs for new disease problems such as fungicide-resistant fungal strains and for older disease for which control measures are deficient." (K. S. Yoder)
Note that Drake combines research and extension objectives, while Yoder separates them.
For the 1992 Comprehensive Review of the Department, Yoder made the following statement (pp. 185 - 186.):
"A research-extension appointment at a field station in the leading fruit county in the state must include extensive field research. Research and extension activities are closely integrated and many activities cannot be categorized as solely research or extension. Research objectives are: To compare effectiveness and safety of experimental and standard disease control chemicals, including control spectrum and fruit finish effects, to provide data for registration or re-registration of useful materials; to determine ways to optimize fungicide performance with spray additives and cultivar disease resistance; to develop control programs for new disease problems; to develop integrated approaches to control problems affecting tree longevity. Most current tree fruit disease research falls under the department program areas of disease monitoring and prediction, impact/loss assessment, and management strategy development using chemical, genetic, and biological approaches. Tree fruit disease extension objectives include department program areas of disease identification, monitoring, prediction, and management. General extension program objectives are: To provide the Virginia fruit industry with economical disease control recommendations necessary to maintain production; to alert growers to unusual disease conditions or problems that can be avoided by prompt precautionary measures; to advise growers of changes in fruit pesticide regulations that affect their operations.
Research Focus - The needs of the tree fruit industry for reliable control measures have changed rapidly over the past four years because of resistance to preferred fungicides, the withdrawal of registration and need for re-registration support of several useful, older materials and growers' recognition of the need to reduce pesticide usage because of economic, environmental and food safety concerns. In some cases, partial re-registration has allowed continued usage but only at reduced, less effective rates, lengthened pre-harvest intervals or lengthened worker re-entry times, and per acre per year restrictions.
The sudden withdrawal of the EBDC fungicides (mancozeb, metiram and zineb) in 1989 resulted in shortages and higher prices for alternative materials to use as companion fungicides for benzimidazole and SI fungicides and for broad spectrum summer disease control. Efforts to find replacements for the EBDC fungicides for early and late season apple disease control zeroed in on captan and ziram. Residue tests conducted in cooperation with the EBDC/ETU Task Force in 1990 permitted partial re-registration of mancozeb and metiram, but only at half rates no closer than 77 days to harvest. Ongoing research focuses on how best to supplement half rates of EBDC's with other fungicides to give the economical control expected from full rates of EBDC's. In spite of the weaknesses of remaining fungicides, we are trying to improve disease management by utilizing spray adjuvant "extenders' such as pinolene and latex derivatives. Another area with potential for reduced fungicide usage is in host resistance. Approximately 25 scab-resistant apple cultivars are now available commercially. In cooperation with horticulturists at Winchester and Blacksburg, we are selecting scab-resistant cultivars which have potential processing quality and screening them for susceptibility to other major diseases. Fruit evaluations will begin next year.
Postharvest apple and peach disease control remains a serious concern because the registrations of two preferred benzimidazole fungicides have been withdrawn for all postharvest food uses and the only non-benzimidazole is captan. Iprodione applied as a post harvest dip treatment gave good experimental control of Penicillium blue mold and brown rot which have developed resistance to the benzimidazole fungicides. Several other potential post harvest treatments will be tested. Chlorine has disinfectant properties, but because of possible phytotoxicity, would add logistical complications to the current practices. Calcium treatments increase fruit resistance to decay, but storage operators are concerned about corrosion of equipment. Biological suppression of fungal decay holds interest because this method could reduce reliance on chemical control. Biological treatments will be tested if stable formulations of organisms become available.
In a cooperative study with NYSAES virologists to test viral cross-protection, pre-inoculation of red Delicious/MM 106 trees with an avirulent Tomato Ring Spot Virus isolate appears to have delayed the onset of severe graft union necrosis symptoms. These trees will be observed for several more years.
Extension Focus - Disease control recommendations are provided through fruit schools, extension bulletins, newsletters, and personal communication with county agents, grower and grower service organizations, and individual grower contacts. Answers to numerous grower questions regarding fungicide effectiveness, and expansion or retention of the registration status of useful materials have been facilitated through laboratory, greenhouse, and field research with fungicides and spray additives. Such questions concern new fungicides, new formulations, or older compounds and alternatives to the EBDC and benzimidazole fungicides and ones more likely to receive adverse publicity. Since Dr. Charles Drake's retirement in 1989, I have participated in several additional meetings in the southern Virginia fruit areas, and there are more frequent phone calls from these areas. Our weekly newsletter is distributed electronically to all counties in Virginia. To improve growers' abilities to identify orchard pest and disease problems, we are working cooperatively within the region (VA, WV, MD, PA, and NJ) on production of a Mid-Atlantic Orchard Monitoring Guide.
Fruit fungicide testing has not been conducted in southern Virginia since Dr. Drake's retirement. Summer disease pressure in the central and southern Virginia areas has exposed some weaknesses of apple disease management programs. A new disease, Alternaria leaf blotch, as appeared in some southern Virginia orchards, stressing the need for improved controls. Variable weather conditions from region to region have exposed the difficulty in making state-wide control recommendations based only on fruit fungicide tests conducted in the Winchester area, but present staffing limitations preclude routine testing in other areas."
The following statements were prepared by Yoder for the 2000 Comprehensive Review (pp. 359 - 361.).
"Issue: the needs of the tree fruit industry for reliable disease control measures are continually changing because of resistance to preferred fungicides, potential withdrawal of registrations due to the Food Quality Protection Act (FQPA) and the recognition of the need to reduce pesticide usage because of economic, environmental and food safety concerns. Ten or more apple diseases and several peach diseases can have an economic impact on commercial production in Virginia each year. Research programs must be flexible for pathogen spectrum changes, development of resistance to fungicides, changes in material registration, or discovery of a new disease.
What Has Been Done: Compare effectiveness and safety of new and registered disease management chemicals. Our research has addressed the changing needs of the tree fruit industry for reliable disease control measures. For example, we identified captan and ziram as replacements for the ethylene bis dithiocarbamate (EBDC) fungicides for apple disease control in 1990. The EBDC's represented about 60% of the fungicides used on apples before they were suddenly withdrawn in 1989. They had been widely used as companion fungicides for benzimidazole and sterol-inhibiting (SI) fungicides and for broad-spectrum summer disease control. Our discovery of suitable replacements helped to reduce fungicide shortages and stabilize prices for alternative materials through the 1990's. Our research has also provided a database upon which to draw when emergencies appear, such as resistance to fungicides, changes in material registration, or discovery of a new disease.
Our research has aided in the registration of newer fungicides such as the SI's, fenarimol and myclobutanil, for broad-spectrum early season apple disease control. These fungicides give the apple grower more options because their control spectrum includes mildew and rusts, and their unique mode of action on scab became particularly significant with the onset of resistance to the benzimidazole fungicides in the apple scab fungus in much of the region's apple acreage. Since 1995, our research has determined the useful broad-spectrum nature of kresoxim-methyl (Sovran) and trifloxystrobin (Flint), low-risk, low-use-rate strobilurin fungicides registered for apples in 1999.
Integrate management practices. In addition to facilitating replacement of older fungicides with new, low-use rate compounds, we have found ways to incorporate cultivar disease resistance into orchard planting and disease management schemes. Our research has determined mildew threshold levels for the unique cultivar, Ginger Gold, and elucidated the economic parameters on which treatment selection should be based. Commercial adoption of new cultivars broadens consumer options in the market place, and disease-resistant cultivars reduce long-term reliance on fungicides.
Manage fireblight. Our research in the 1990's has provided several answers to control of potentially devastating fireblight which has become a major concern for the highly susceptible apple rootstocks and cultivars now being planted. Based on our background research, most growers are now applying copper materials to processing market cultivars at apple green tip stage to help reduce fireblight potential and to offset development of resistance to the only other registered control, streptomycin. Also, many growers and consultants are monitoring weather and bloom conditions and use a predictive system on which to base need for protective streptomycin. Finally, our novel research on the reduction of tree susceptibility by the growth regulator, prohexadione-calcium, initiated in 1994, may revolutionize fireblight management recommendations world-wide. Discussions about this material with EPA in 1998 helped facilitate its reduced-risk status and subsequent commercial registration as Apogee in April, 2000.
Impact: We have generated economical and environmentally sound disease management recommendations for growers and fruit crop production advisors in Virginia and the mid-Atlantic region. Our discovery of suitable replacements helped to reduce fungicide shortages and stabilize prices for alternative materials through the 1990's. Our research over the past five years revealed the useful broad-spectrum nature of kresoxim-methyl and trifloxystrobin, strobilurin fungicides that gained registration for apples in 1999. These low-risk, low use rate material will help to offset some of the impact of FQPA on tree fruit production. We were the first to try the approach of using a plant growth regulator to suppress apple shoot susceptibility to fireblight. Prohexadione-calcium now being tested world-wide wherever fireblight is a problem on apples and pears, particularly in Europe where other options are limited. Adoption of this practice will reduce excessive use of streptomycin and will help to maintain its effectiveness in the mid-Atlantic region.
We emphasize orchard monitoring for diseases and timely, efficient use of management measure to reduce overall chemical inputs. We have determined ways to incorporate cultivar disease resistance into orchard planting and disease management schemes. Our research has determined mildew threshold levels for the unique cultivar, Ginger Gold, and elucidated the economic parameters on which treatment selection should be based. Commercial adoption of new cultivars broads consumer options in the market place, and disease-resistant cultivars reduce long-term reliance on fungicides.
We transmit information through presentations at fruit schools, regional extension and research meetings. Specific information is provided in the areas of varietal resistance susceptibility to diseases, disease management, fungicide effectiveness and management decisions related to fungicide usage, proper utilization of fungicides to avoid resistance to fungicides, and effects of weather on disease development. Adoption of these management practices increases grower profitability and helps to assure a safe supply of fruits to the consumer. In addition to conventional methods of information delivery such as area fruit schools and extension publications, we have utilized the Mid-Atlantic tree fruit web site with Dr. Alan Biggs, WVU and the Fruit Loop site with Dr. Doug Pfeiffer at Virginia Tech. We posted 11 tables of varietal disease resistance/susceptibility information and 17 disease fact sheets on the WVU Mid-Atlantic tree fruit web site. During the bloom period, we display graphics showing fireblight disease forecast information. In 1998-99, materials that I authored or co-authored and posted at the WVU and Va. Tech sites were accessed 39,059 times (page view or download data). 1999 site usage nearly tripled over 1998 because of the increasing popularity of these sites."
Although these statements were prepared in 2000, most of the research was completed in the Moore Era. These statements also highlight the increasing dependence on electronic communication. The fungicide testing is documented in the American Phytopathological Society annual publications Fungicide and Nematicide Tests vols. 40 through 53, 1985 - 1998 and Biological and Cultural Tests vols. 9, 11, 12. 1994, 1996, 1997. Information for fruit growers was updated and published annually in:
(1) Pest Management Guide for Horticultural and Forest Crops. Va. Coop. Ext. Pub. 456 - 017.
(2) Pest Management Guide for Home Grounds and Animals. Ibid. 456 - 018.
(3) Spray Bulletin for Commercial Tree Fruit Growers. Ibid. 456 - 419. (This bulletin is prepared and issued jointly by extension services of Virginia, Maryland, and West Virginia.)
In (1) above, sections were devoted to (a) commercial small fruits and (b) grapes. Yoder prepared (a) and Baudoin (b). In (a) subsections were diseases of strawberry, brambles, and blueberry.
Baudoin gave special attention to the fungus disease control needs of grape growers. Starting in 1989, he studied interactions among fungicides that were available for control of black rot and other important diseases with the aim of identifying antagonistic and synergistic combinations. Such combinations were found in laboratory studies, but they were of little value in vineyards. He also made a field study of spreader-sticker application on flower cap retention and Botrytis rot, a survey for Botrytis cinerea strains resistant to two fungicides recommended for it's control, and field tests to determine the optimum timing of applications. Results from these experiments were incorporated when feasible into the grape diseases section of Va. Coop. Ext. Pub. 456 - 017.
Baudoin's report that iprodione-resistant strains of B. cinerea existed in several vineyards in northern Virginia was the first for the United States. Benomyl-resistant strains were also reported (Plant Dis. 78: 102 - 1994.). Baudoin et al. found that floral debris could be removed from young fruit clusters with a leaf blower; however, the procedure only slightly reduced the incidence of B. cinerea bunch rot. The control gained was deemed not economically feasible (Vitis 36: 27 - 33. 1997.).
Sue Tolin investigated the occurrence of virus diseases in a nursery planting of grape rootstock cultivars and found several of over 400 vines examined to be infected with tomato ringspot virus (TmRSV). Infected plants were removed and destroyed. She was assisted by Dr. David Bays, a former graduate student who majored in plant virology as an advisee of Tolin. The work aided in refining Virginia's grapevine certification program. As a member of Virginia's Viticulture Technical Advisory Committee, Tolin had assisted in developing the State's grapevine certification program. The program was transferred to Mike Likens, Plant Pathologist, Virginia Department of Agriculture and Consumer Services, where it remains a function of the state's nursery stock certification program.
Much of the fruit virus research was in collaboration with Yoder and was a contribution to NE-14, Northeast Regional Research Project, Virus and Mycoplasma Diseases of Deciduous Tree Fruits and Grapevines. Yoder was a member of NE-14 Technical Committee and was its Chairman in 1993. The research was, also, a contribution to IR-2/NRSP-5, Inter-regional Project to Derive, Preserve, and Distribute Virus-free Germplasm. Yoder was a member of its Technical Committee, Chairman in 1994.
In 1990, the American Phytopathological Society published the Compendium of Apple and Pear Diseases (A. L. Jones and H. S. Aldwinckle, eds.). Drake and Yoder contributed write-ups on several diseases.
Yoder authored or co-authored the following:
Powdery mildew - K. D. Hickey and Yoder; brooks fruit spot, blotch, black pox of apple and blister canker of pear, x-spot, all by Yoder. Yoder also contributed two illustrations.
Drake contributed the following:
Black root rot, Armillaria and Clitocybe root rots, southern blight, white root rot and Phymatotrichum root rot (with R. D. Hine).
Both Drake and Yoder contributed many other publications useful to the fruit industry. Yoder's work has continued well beyond the Moore Era.
Two thesis bearing on fruit pathology were completed during the Moore Era:
Scamack, Anita M. 1991. Apple powdery mildew: Literature and research overview. M. S. Thesis. V.P.I. & S.U.
Martinez, Natalia. 1992. Relationship among spreader-sticker application, blossom cap retention, berry scarring, thrips populations, and Botrytis bunch rot in Chardonnay grapes, and a survey of pesticide use and pest severity in Virginia vineyards in 1990 and 1991. M. S. Thesis. V.P.I. & S.U.
Scamack found that fungicides, host resistance, and epidemiology had received most research attention. Lacking attention were roles of cleistothecia, ascospores, hetero- versus homothallism, growth of Podosphaera leucotricha on artificial media. Yoder served as her committee chairman.
Martinez found that the spreader-sticker product, Nu-Film 17, increased flower debris retention slightly, and removal of flower caps had no effect on berry scarring, but reduced Botrytis bunch rot slightly. Thrips control with methomyl reduced berry scarring, but did not affect the incidence of rot. Black rot, Japanese beetle, and annual grasses were considered by growers to be the most important pests. These were most frequently controlled with captan, carbaryl, and glyphosate. Anton Baudoin and M. J. Weaver were co-chairmen of her committee.
In the Moore Era, research emphasis was on breeding disease-resistant cultivars, genetic analysis of soybean-virus interactions, analysis of a Fusarium-induced disease that occurred most frequently in the cv. Essex, hence, named the Essex disease. The Essex disease studies will be related first.
In the late 1970's when Essex was the predominant soybean cv., complaints were received from a number of growers about the inability of the cv. To produce the expected growth and seed yield on certain sandy soils. Graduate student C. Earl Grant studied the disease for his M. S. Project. With Roane and Phipps as co-advisors and Griffin as committeeman, Grant produced a project and report entitled "Etiology and control of a damping-off disease of soybeans in Virginia", (M. S. Proj. and Rept., V.P.I. & S.U., 1980.), in which he reported that Fusarium oxysporum and F. solani caused the disease to different degrees in Essex, 'McNair 500,' and 'Lee 68.' Grant treated the disease as a damping-off problem which he could control with several seed-treatment fungicides.
Griffin, being interested in soil fungus plant interactions, studied the disease for several years and guided two students through thesis projects pertaining to the problem that became known as the "Essex disease". Graciela M. Farias titled her thesis, "Quantitative investigations of Fusarium oxysporum and F. solani colonization and rot of Glycine max cv. Essex seedlings." (M. S. Thesis, V.P.I. & S.U., 1987.) In addition to Fusarium spp., Farias identified Rhizoctonia solani as contributing to the Essex disease syndrome especially at higher temperatures. (See, also, Farias, G. M., and G. J. Griffin. Plant Dis. 73: 38 - 42, 1989. Plant and Soil 123: 59 - 65, 1990.).
Pathogenic and non-pathogenic isolates were found and Ozlem Kilic made a study of these under the title, "Effect of dsRNA - containing and dsRNA-free hypovirulent isolates of Fusarium oxysporum on severity of fusarium seedling disease of Essex soybean." (M. S. Thesis, V.P.I. & S.U., 1997.). Kilic found no correlation between presence or absence of dsRNA and virulence or hypovirulence of F. oxysporum. (Kilic and Griffin, Plant and Soil 201: 125 - 135, 1998.).
Griffin recognized that Pythium ultimum played a role in the damping-off phase of the Essex disease and later by colonizing rootlets thereby contributing to the late phase. This was discovered when he observed that metalaxyl seed treatment reduced the impact of the disease (Griffin, Canad. J. Pl. Path. 12: 135 - 140, 1990.). Metalaxyl is specific for controlling Phycomycete diseases. 1990.). Thus, the Essex disease was shown to be a complex disease caused by two Fusarium spp. and a Pythium.
Stromberg tested a number of seed-treatment fungicides. The results of these tests led to recommendations published in the Pest Management Guide (Va. Coop. Ext. Publ. 456 - 016, rev. annually.). Criteria for treating soybean seed were based on germination percentages of seed lots and soil temperature at planting time. In general, seed germinating 85% or better did not require treatment unless the soil temperature was below 85° F. If germination was 75 - 85%, seed should be treated, and if below 75%, should not be used for seed. Several fungicides were recommended singly or in combination with other fungicides. None was universally effective. Thiram was the best general fungicide; carboxin was best against Rhizoctonia; metalaxyl and related compounds were best against Pythium and Phytophthora.
According to John D. Eisenback, PPWS nematologist, root knot and cyst nematodes are the most damaging of the various nematodes in Virginia soybean soils. In the Pest Management Guide are lists of cultivar reactions to Meloidogyne incognita, M. arenaria, and Heterodera glycines for maturity groups III to VI which might be grown in the Middle Atlantic region. No resistance occurs in the publicly released cvs. from Virginia. Abundant resistance is available for races 3, 9, and 14 of the soybean cyst nematode (H. glycines) but little is available for root knot nematodes. Thus, root knot must be managed by cultural means and nematicides. The nematode Advisory Program developed in Virginia (see section on Peanut) is applicable to and available for soybean production.
Soybean viruses have been the subject of intensive investigation in Virginia. Soybean mosaic virus (SMV) is destructive worldwide and is easily disseminated through seeds. In the peanut area in particular, peanut mottle virus (PMV) and peanut stunt virus (PSV) are most prevalent. Resistance to these three viruses has been found and deployed in the triply resistant soybean cvs. Toano and Hutcheson. Bean pod mottle virus (BPMV) resistance has not been found in Virginia; it would be useful because it seems to be very common adjacent to crimson or red clover fields. Several other viruses occur occasionally in Virginia, but their frequency does not warrant breeding for resistance to them. Since SMV is seed-borne, continued breeding for resistance is warranted not only to prevent damage in production fields, but also to block seed transmission.
Roane, Tolin, and G. R. Buss initiated inheritance studies with soybean viruses during the Foy Era. They prepared a manuscript describing the results of a cross of 'York' x 'Lee 68,' York being resistant to SMV and PMV susceptible to PSV; and Lee 68 being resistant to PSV, but susceptible to SMV and PMV. Thus, an inheritance of reaction to three viruses was studied simultaneously. The paper was submitted to the Journal of Heredity, but since the data were "not clean" for PSV the editors would accept only the SMV and PMV data. Single dominant genes for the two virus resistances were linked by 3.7% recombination (J. Heredity 74:289 - 291, 1983.). The inheritance of reactions to three viruses was reported in the Soybean Newsletter (7:100 - 102, 1980.) and an abstract in Phytopathology (70:692, 1980.). This work is reviewed because it laid the ground work for breeding soybean cvs. with triple virus resistance.
Once resistance genes were identified and the routine of obtaining reactions of soybean lines and cvs. to viruses was established, the breeding of virus-resistant cvs. became a major objective of Buss' breeding program. Toano was released in September 1985 from lines tested in the virus inoculation program (Crop Sci. 27: 1092, 1987.). In addition to viruses, it was resistant to downy mildew (Peronospora manshurica) and purple stain (Cercospora kikuchii). With like virus resistance, Hutcheson was released in 1987 by the Virginia, Alabama, Georgia, Kansas, Missouri, and Tennessee Experiment Stations. It, also, was resistant to bacterial pustule (Xanthomonas campestris pv. phaseoli), downy mildew, and purple stain (Crop Sci. 1024 - 1025, 1988.). It became the most widely grown cv. in the Southeast.
After it was demonstrated that York carried linked monogenes for SMV and PMV and Shipe found a second gene for PMV resistance (Crop Sci. 19: 656 - 658, 1979.), Buss, Roane, Tolin, and graduate student T. Vinardi determined that 'CNS' has resistance for PMV at a locus different from that of 'Dorman' (and York). Thus, three genes were labeled, Rpv1 in Dorman, Rpv2 in 'Peking', and Rpv? in CNS. Since no allelism tests have been conducted involving all three genes, the exact relationships have not been established and all labels are tentative (Crop Sci. 25: 314 - 316, 1985.). No further genetic tests were executed in the soybean-PMV realm.
With Tolin and Roane as co-advisors, D. C. Bays prepared a dissertation entitled, "Variability of the peanut mottle virus reaction in soybean" (Glycine max) (Ph. D. Diss., V.P.I. & S.U., 1983.) and later published a paper summarizing it. From inoculation experiments with five strains of PMV, he demonstrated five patterns of reactions typified by Lee 68, 'Cumberland', 'Virginia', Dorman, and Peking. Peking and CNS fell in the same reaction class which suggested they might have identical genes (Phytopathology 76:764 - 768, 1986.). Thus, the genetics of PMV reactions in soybean remains unclear; efforts were turned toward unraveling the genetics of the SMV-soybean interactions.
Until 1989, no additional journal publications were issued from V.P.I. & S.U. on genetics of soybean-virus reactions, although two unreviewed papers were published in the 1986 Soybean Genetics Newsletter (SGN 13: 136 - 138, 139 - 143.) In the first, 'Marshall' and 'Kwanggyo' were shown to be monogenic at a common locus; P.I. 96983 was digenic in reaction to SMV strain G1. The genes in P.I. 96983 were not tested for allelism with the other two genes.
In the second SGN paper, a gene-for-gene hypothesis was proposed for the soybean-SMV interactions. From the tabular information, it can be seen that Kwanggyo and Marshall reacted differently to SMV strains G2, -3, and -5; thus, they must have different alleles at the same locus. After some refinements of the data (identifying viruses in susceptible plants of mostly resistant rows as not being SMV), the paper was published by Buss, Roane, Tolin, and P. Chen (Crop Sci. 29: 1439 - 1441, 1989.). This was Chen's introductory work with genetics of virus reactions in soybean. As a graduate student in plant breeding, he would make significant contributions to the soybean-virus genetics.
At two World Soybean Research Conferences (III: 433 - 438, 1985; IV: 1144 - 1154, 1989.), Buss presented papers in behalf of the V.P.I. & S.U. soybean research team (Buss, Roane, Tolin, and Chen) describing the work on soybean-virus genetics and breeding virus resistant soybeans; SMV was emphasized, PMV was included, but PSV was not. On a world basis, SMV deserved center stage.
P. Y. Chen as Buss' advisee prepared a dissertation entitled, "Genetics of reactions of soybean mosaic virus in soybean," (Ph. D. Diss., V.P.I. & S.U., 1989.). In a published version, he reported that even though there were differences in reaction among five cvs., they did not produce segregating F2 and F3 when crossed and tested with SMV strain G1. Thus, all genes were at a common locus and were considered alleles. The symbols assigned in the respective cvs. Were: P.I. 96983, Rsv1; Ogden, Rsv1t; York, Rsv1y; Marshall, Rsv1m; and Kwanggyo, Rsv1k. Having these genes all at one locus created a road-block for pyramiding genes in a single cv. (Chen, Buss, Roane, and Tolin, Crop Sci. 31: 305 - 309, 1991.).
In the genetics of reaction to viruses, three responses were recognized: resistant, necrotic, and susceptible. In the past, if a plant responded to virus inoculation, it was considered susceptible by virologists. However, from the outset, Virginia workers grouped plants in progenies as non-susceptible or susceptible. The non-susceptible class included resistant (R) and necrotic (N) segregants. Such a grouping would usually provide acceptable F2 fits to monogenic and digenic ratios with resistance dominant. Grouping N and susceptible (S) plants together would usually give acceptable 1:3 ratios, but resistance would be recessive. Necrosis was observed to occur mostly in segregating populations; thus, it was thought to be a response of heterozygous plants. In F2, the frequency of N plants was often high enough to give a 1:2:1, R:N:S; thus, workers who did not classify F3 chose to group N with either R or S. Resistance then would be either dominant or recessive. In F3, F2, R plants would produce all three classes. However, with some SMV strains, the N reaction was typical for some cultivars. Chen made a genetic study of the N reaction as part of his dissertation project. In N X S, F2 progenies segregated 3N :1S; no S segregants occurred in N X N and R X R F2 progenies. In R X S F2 progenies, R, N, and S segregants appeared in a 3 (_ + N) : 1S ratio. These events were conditioned by the choice of SMV strain. This study seemed to solve the enigma of N reactions and how to classify them in genetic studies of the soybean-SMV interactions (Crop Sci. 34 : 414 - 422, 1994.). Even so, interpreting the N class for genetic purposes may remain different from that for virology purposes.
By 1991, results from genetic experiments seemed to indicate that reaction to SMV was governed by genes at 4 loci with resistance-inducing alleles occurring at Rsv1 and Rsv3. Chen et al. made excellent use of the gene-for-gene table that Roane et. al. proposed in 1986 (Soybean Genetics Newsl. 13: 139 - 143.) from which he recognized discrepancies in gene labeling. Apparently, some genes had been labeled without having been tested for allelism with previously with previously labeled genes. As a consequence of Chen's efforts, Rsv2 was shown to be an allele at Rsv1 and was relabeled Rsv1; thus, Rsv2 disappeared.
Buss advisee Guorong Ma completed his Ph.D. research in 1995 (Ma, G., Genetic analysis of soybean reactions to soybean mosaic virus. Ph.D. Diss., V.P.I. & S.U., 1995.) in which he reported on the genetic constitution of SMV reactions in 'PI486355' (Theor. Appl. Genes 91: 904 - 907, 1995.). The two genes in PI486355 were separated and their reactions to appropriate strains of SMV observed. In resistant line1, LR1, a new allele, Rsv1s, was determined; in LR2 and independent gene that confers resistance to SMV strains G1 - G7 was isolated and labeled Rsv4.
Buss, Ma, Chen, and Tolin released a line, V94 - 5152, derived from the cross Essex X PI486355, because it carried the two genes discussed above and does not give a necrotic response to any strain of SMV (Crop. Sci. 37: 1987 - 1988, 1997.).
During the Moore Era, Buss and Tolin and their students contributed significantly to the genetics of soybean-SMV interactions. They have undertaken the breeding of a series of near isogenic lines of 'Essex', each having one of the Rsv alleles (Va. J. Sci, 39:92, 1988.). The entire collection of SMV genetic studies probably has had little impact on the health and production of Virginia-grown soybeans, but has been very useful to soybean breeders on a world-wide basis.
M. A. Saghai-Maroof was appointed in the Crop and Soil Environmental Sciences Department in 1989 to lead studies in molecular aspects of crop genetics. One of his advisees, Yong Yang Yu, made a "Molecular genetic analysis of host resistance to soybean mosaic virus" (Ph.D. Dissertation, V.P.I. & S.U., 1994.). By using restriction fragment length polymorphisms (RFLPs) and simple sequence repeats (SSRs), he studied the Rsv1 locus in the cross of SMV-resistant 'P.I.96983' with 'Lee 68'; progenies were inoculated SMV-G1. He found Rsv1 linked with SSR-HSP176L and RLP pA186 and pK6441 at distances of 0.5, and 2.1 cm, respectively. He confirmed that such tight linkages occurred in three other lines carrying Rsv1 derived from either P.I.96983 or 'Marshall'. The same three Rsv1-linked markers were used to screen 67 diverse soybean types. The results agreed with available pedigree information. Thus, the method is useful in identifying gene loci for breeding purposes. The need for conventional genetic tests is obviated. Other factors not related to pathology were also found linked to Rsv1. Yu also established that Rsv1 is a small cluster, but no dimension was given. There was no reference to alleles at the Rsv1 locus.
This work was the first to apply molecular technology to the genetics of the soybean-SMV interactions. Yu published with members of his Ph.D. committee two papers based on his dissertation (Yu, Saghai Maroof, Buss, Maughan, and Tolin. Phytopathology 84:60 - 64, 1994; Theor. Appl. Genet. 92:64 - 69, 1996.).
In a later study, Yu, Buss, and Saghai-Maroof reported that genes for resistance to two viral and two fungal diseases tended to occur in clusters. Such a phenomenon suggests that there is some commonality in resistance mechanisms for diseases in general, and clustering may be a conservation mechanism in the host. The diseases were soybean mosaic, peanut stunt, Phytophthora root rot, and powdery mildew (Isolation of a superfamily of candidate disease-resistance genes in soybean based on a conserved nucleotide binding site (Proc. Natl. Acad. Sci. USA 93:11751 - 11756, 1996.).
In a study employing a patented technique (Keygene, Inc.), amplified fragment length polymorphism (AFLP), P. J. Maughan, Saghai-Maroof, Buss and G. M. Huestis examined cvs. carrying Rsv1 and Rsv3 (SMV resistance genes). Detection of gene loci by AFLP analysis is cheaper and less time-consuming in soybean: (Species diversity inheritance, and near-isogenic line analysis, Theor. Appl. Genet. 93:392 - 401, 1996.). Thus, during the Moore Era, molecular genetics made considerable strides at Virginia Tech.
During the Moore Era, Tolin mentored five graduate students through studies on the soybean mosaic virus. The students and their thesis or dissertations were:
Paul L. Gunyuzlu - The nucleotide sequence of the 3' terminus of soybean mosaic virus. M. S. Thesis, V.P.I. & S.U. 1987.
Chang W. Choi - Soybean mosaic-soybean interactions: Molecular, biochemical, physiological, and immunological analysis of resistance of soybean to soybean mosaic virus. Ph.D. Diss. V.P.I. & S.U. 1991.
Torun Gera - Tracking soybean mosaic virus movement in soybean by leaf imprint immunoassay. M. S. Thesis. V.P.I. & S.U. 1994.
Saba J. Qusus - Molecular studies on soybean mosaic virus-soybean interactions. Ph.D. Diss. V.P.I. & S.U. 1997.
Tolin advisee, Jonathan P. Flora, completed an M.S. thesis in 1997 entitled, "The effects of temperature on the durability of resistance of soybean to soybean mosaic virus." There were reports in the literature from Tu and Buzzell in Canada that the resistance conferred by Rsv3 broke down under high temperature. Flora tested cvs. Carrying rsv, Rsv1-y, Rsv1-t, and Rsv1 alleles of Rsv1 inoculated with SMV strains SMV-G1, -G4, and G-6 after exposure to 20° and 30° C. It was expected that after exposure to 30°, heat shock proteins would be produced which would alter cv. response to virus. No such alterations were observed. Flora concluded that alleles at the Rvs1 locus are heat-stable.
Obviously, all of the above are more fittingly discussed in the section "Virology" than under "Soybean" where the subject is soybean pathology. It can be rightly said these theses/dissertations are etiological studies on a soybean pathogen, but their objectives, methodologies, and findings merit a section of virology.
Research and extension activities on peanut pathology were carried out at the Tidewater Agricultural Research and Education Center (TAREC) in Suffolk (formerly Holland, Nansemond County until the county became the city of Suffolk). During the Moore Era, Patrick M. Phipps of PPWS, V.P.I. & S.U., and D. Morris Porter, USDA, ARS, were in charge of the research. Porter's tenure at TAREC ended in 1995 when the USDA closed out its peanut projects at Suffolk and he was transferred to Maine for his final year as a federal employee. Phipps held a split appointment, 40% research and 60% extension. The two worked together on several research projects and published jointly several journal articles.
A major contribution by Porter was to serve as editor of the Compenium of Peanut Diseases published by the American Phytopathological Society (APS) Press, First Edition 1984, Second Edition 1997. For the 1984 edition, editors were Porter; D. H. Smith, Texas A & M University; and R. Rodriguez - Kabana, Auburn University. For the second edition, editors were N. Kokalis-Burelle, Auburn, Porter; Rodriguez - Kabana; Smith; and P. Subrahmanyam, Malawi. Porter also prepared the following sections: Introduction, The Peanut Plant Peanut Diseases; Fungus Diseases, Botrytis Blight, Diplodia Collar Rot (with Phipps), Neocosmospora Foot Rot, Sclerotinia Blight (with H. A. Melouk); Abiotic Diseases, Drought Stress, Frost Injury, Genetic Disorders, Hail Injury and Lightning Injury. Phipps contributed sections on Cylindrocladium Black Rot (with M. K. Beute), and Diplodia Collar Rot (with Porter). Both contributed several color photographs. The Compendium is a significant contribution to peanut pathology.
Peanut leafspot (early = Cercospora arachidicola; late = Cercosporidium personatum) holds the distinction of being the longest researched peanut disease in Virginia. Efforts to control it by L. I. Miller beginning in 1938 have been described in the Wingard, Couch, Foy, and Hooper Eras. Throughout these periods, the use of foliar applied fungicides has remained the most reliable control measure. Porter studied the effects of changing management practices and reported that conventional tillage (plowing and disking) delayed the onset of leafspot more than conservation tillage (unplowed, wheat winter cover) (Proc. Am. Peanut Res. Educ. Soc. 22:44, 1990.). Earlier planting dates, earlier harvest dates did not produce the benefits from fungicides that later dates did (Ibid. 22:60, 1990.). As little progress had been made in breeding leafspot resistant cultivars, a mechanical procedure for grading plants or plots for severity of leafspot was tested. Called "machine vision technology", results obtained by human and machine scoring were comparable and five cultivars were similarly ranked. The method could speed up plot cultivar evaluation (Ibid. 26:47, 1994.). By 1997, some exotic sources of resistance had been isolated (Ibid. 19:53, 1987; 23:21, 1991; Peanut Sci. 19:41 - 43,1991; Biol. & Cult. Tests 7:57, 1992; 9:101, 102, 1994.).
In an effort to reduce the cost of applying fungicides, the method of N. L. Powell, Porter, and Roberta Dow (Proc. Am. Peanut Res. Ed. Soc. 12:41, 1980.), i.e., the peanut leafspot advisory, was continually evaluated, revised, and modernized until it is a vital part of the extension peanut project led by Phipps; cost of leafspot control was cut in half by this innovation (Plant. Dis. 81: 236 - 244, 1997.).
"The Virginia Peanut Leafspot Advisory (VPLA) was first delivered to peanut growers in southeast Virginia in 1981, and has allowed growers to reduce the number of fungicide applications per cropping season (Phipps and N. L. Powell, Phytopathology 74:1189 - 1193, 1984.), but fungicide sprays according to the VPLA in some years allowed development of disease late in the season to levels which caused concern among growers. The need to improve the leafspot advisory program was suggested by Elspeth L. Jewell. (Correlation of early leafspot disease in peanut with a weather-dependent infection index. M.S., Thesis. V.P.I. & S.U. 1987.)." This quote is from R. S. Cu. (Development and evaluation of a computerized leafspot advisory program for effective use of cultivar resistance, fungicide, and spray adjuvant to control early leafspot of peanut. Ph.D. Diss. V.P.I. & S.U. 1991.).
As the leafspot advisory was developed and refined, getting the appropriate information to the growers became a problem. "This obstacle was overcome in 1979 with the implementation of an environmental monitoring system developed through cooperative research by Virginia Tech, the National Aeronautical and Space Administration (NASA), and the U. S. Department of Agriculture" (Phipps. Plant Dis. 77:307 - 309. 1993.). This has evolved into the Peanut/Cotton InfoNet which offers advisories daily on an electronic bulletin board. A personal computer, communications software, and a modem with phone connection are required to access the bulletin board" (Phipps, 1999 Field Crops pest Management Guide, Va. Coop. Ext. Publ. 456 - 016, 1998.).
More is said about the advisories toward the end of the section on Peanut.
Porter, with others, evaluated the effects of irrigation on peanut. Overhead irrigation caused increased severity of Sclerotinia blight, pod rot, and early leafspot; consequently, yields were reduced under sprinkler irrigation (Plant Dis. 71:512 - 515, 1987.).
Cylindrocladium black rot (CBR) was one of Porter's major research topics. He and several colleagues studied the colonization and survival of the CBR fungus in seeds. The fungus, Cylindrocladium crotalariae, could colonize seeds but lost viability in storage. Seed transmission was remote if discolored and shriveled seed were removed and the seed were treated with captan or carboxin (Proc. Am. Peanut Res. Educ. Soc. 21:30, 1989; 23:51, 1991; Phytopathology 81:896 - 900, 1991.).
With the introduction of isothiocyanates, particularly metam-sodium (Vapam and Metam) as preplant soil fumigants, damage from Cylindrocladium black rot was minimized.
The increasing prevalence of Sclerotinia blight in the early 1980's stimulated considerable research on its control during the Moore Era. Phipps and Porter both devoted much time and effort analyzing the environmental factors conducive to its development and containment. Phipps and R. W. Mozingo, the plant breeder at Suffolk, sought suitable resistant cultivars. Three graduate students earned Ph.D. degrees by researching the disease. They were T. B. Brenneman, may 1986; F. D. "Tad" Smith, December 1990; and D. B. Langston, April 1998.
Initially, effort was devoted to finding a fungicide that would diminish the losses from Sclerotinia blight. By 1975, dicloran and PCNB were the primary chemicals recommended, but they barely paid for their use. In 1985, iprodione was registered (Smith, T. D., Evaluation of fungicide resistance in Sclerotinia minor and strategies for chemical control of Sclerotinia blight of peanut. Ph.D. Diss., V.P.I. & S.U., 1990.). Although it was much more efficacious than decloran and PCNB, there were cases where it failed completely. In most cases, failure was attributed to timing and methods of application, but occasional cultures with resistance to iprodione were isolated (Smith, 1990.).
In his dissertation, T. B. Brenneman describes methods for studying fungicidal action against Sclerotinia minor (Brenneman, T. B. Sensitivity and resistance of Sclerotinia minor to fungicides for control of Sclerotinia blight of peanut. Ph.D. Diss., V.P.I. & S.U. 1986.). He demonstrated that excised peanut stems could be used "to evaluate isolate pathogenicity, cultivar resistance to the disease, susceptibility of different age peanut tissues, and fungicide persistence on peanut stems in the field. The method was also used to screen fungicides; results verified previous findings which indicated that in vitro resistance is not equivalent to in vivo resistance" (Brenneman, Ph.D. Diss.).
Since it had been demonstrated that several fungi became resistant to chemicals used to control them, Brenneman investigated the possibility that fungicides efficacious against Sclerotinia minor, especially iprodione, might be rendered ineffective by resistant strains. He found nine fungicide-resistant colony sectors; seven maintained resistance through three years of subculturing and two survived in microplots as well as a wild type. Thus, in due time it appeared that iprodione may be rendered ineffective by resistant populations. Several papers were published on this work (Peanut Sci. 12: 41 - 45, 1985; Phytopathology 74: 755, 815, 1984; 77:1028 - 1032, 1987; 78:863, 1988; Plant Dis. 69:143 - 146, 1985; 71: 87 - 90; 71;:546 - 548, 1987; Proc. Amer. Peanut Res. Educ. Soc. 17:43, 1985.). However, iprodione has survived to the year 2000 as the only registered fungicide for Sclerotinia blight control. In 1992, Smith, Phipps, and Stipes reported fluazinam to be a new fungicide for control of Sclerotinia blight (Peanut Sci. 19;115 - 120.), but for some reason it was not registered for commercial use. Through the Moore Era, only the fungicide iprodione (sold as Rovral) was registered for control of Sclerotinia blight (1999 Field Crops Pest Management Guide, Va. Coop. Ext. Ser. Publ. 456 - 016; 115. 1998. Note: Fluazinam was registered for blight control for the 2001 peanut crop.)
Since peanuts require considerable pesticides for quality production and they are produced in coastal plains, they are thought to contribute to chemical contamination of estuaries, bays, and sounds. Ecology-minded scientists began in the Moore Era to seek production methods that would abate the use of chemicals and reduce contamination of water. Emphasis was given by Phipps and his colleagues to use of disease resistant cultivars, biological agents and modifying the environment. Results of these approaches were recorded annually in the American Phytopathological Society publication Biological and Cultural Test (BCT) volumes 1 through 13, 1986 - 1998.
Breeding or finding cultivars resistant to Sclerotinia blight did not yield significant progress. Phipps observed in 1987 that 'Va 81b' and "AD1' expressed some resistance, and later found among six Virginia types "NC6' was most resistant, and among 11 runner types, two Texas lines and "Georgia Green' were best (BCT 3:66, 1988; 13:76, 1998.). Mozingo observed that resistance in Va 81B was highly heritable in his breeding work, and that among 8 large-seeded cvs., a line produced by him, 'Va 910954', was best. However, Langston stated that true resistance to Sclerotinia minor had not been found and that apparent resistance was attributed to architectural characteristics of the canopy, i.e., density and erectness (Langston, D. B., Jr. The role of host, environment, and fungicide use patterns in algorithms for improving control of Sclerotinia blight of peanut. Ph.D. Diss., V.P.I. & S.U., 1998.).
The first biological agent tested by Phipps was Trichoderma harzianum; no significant suppression of disease was noted (BCT 4:40, 1989.). In 1992, Phipps reported on results with several biological agents compared with Rovral and fluazinam. Biologics included Bacillus cereus, B. megaterium, B. subtilis, Pseudomonas putida, P. fluorescens, P. sp, an Actinomycete, Sporidesmium sp., and Trichoderma sp. Fluazinam gave best blight control and highest yield; among the biologics, B. cereus produced the highest yield, one Sporidesmium produced the best blight control and highest yield. The products tested must have been commercially formulated as there was no explanation about their preparation (BCT 7:60, 1992.). A similar trial for leafspot control compared the same bacteria against Bravo 720. No bacteria produced satisfactory control or yield increase (BCT 7:56, 1992.).
For some reason, Phipps and Langston conducted field trials in 1995 on the "nutritional enhancement" for control of Sclerotinia blight with two applications of corn meal at mid-season. Yields and blight control were slightly better for enhanced plots than for untreated plots, about equal to Rovral treatment (the only fungicide registered for blight control), but inferior to fluazinam. (BCT 11:54, 1996.). Similar results were obtained in 1996 (BCT 12:75, 76, 77, 1997.).
Phipps et al. evaluated planting dates, seeding rates, irrigation, and canopy modification in an effort to find optimum cultural management for lessening losses from Sclerotinia blight. By the end of the Moore Era, advisories were issued for pesticide application. These were aimed at control of all diseases for management of the peanut crop to achieve maximum yields with minimum pesticide input. Recommendations for pesticide applications and access to advisory information are revised annually in the "Field Crops Pest Management Guide" (Va. Coop. Ext. Publ. 456 - 016.). Phipps, S. H. Deck (USDA-ARS, Stoneville, Miss.), and D. R. Walker (Walker, Asher, and Scott, Inc., Johnstown, Pa.) published a feature article in Plant Disease 81 (3): 236 - 244, 1997, entitled "Weather-based crop and disease advisories for peanuts in Virginia." They give the details of weather analysis and crop development needed to advise fungicide applications for early leaf spot, Sclerotinia blight, and impending danger of frost at harvest time. They, also, describe weather monitoring networks and information delivery systems. The article was an excellent presentation of the status of peanut advisories at the time.
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