Dr. Joe Vargas

Research Technicians

Ron Detweiler  Vargas Lab
Nancy Dykema Vargas Lab 
Contact Information: 517-353-9082

2007 Disease Resistant Bentgrass Proposal

Introduction
Disease control continues to be a costly challenge for golf course superintendents requiring repeated fungicide applications throughout the growing season.  One of the major diseases facing superintendents is dollar spot.  The dollar spot fungus is becoming more resistant to all of the classes of fungicides.  Dollar spot control often consumes a large portion of the fungicide budget.  One means of reducing this cost, as well as overcoming the resistance problem, would be to have access to a disease-resistant bentgrass cultivar.

Several years ago, dollar spot resistant creeping bentgrass clones were found and collected from an old, segregated bentgrass green.  These clones proved to be far more resistant to dollar spot than the most resistant commercial bentgrass varieties.  These selected clones (MSU-2 and MSU-3) are being used to develop a dollar spot resistant bentgrass cultivar for commercial release.  In the multi-year process of developing a cultivar, crosses are made, the resultant progeny are screened for the desired traits (disease resistance and other desirable agronomic characteristics) and the best progeny are selected to undergo further development.

During 2004, we established a space plant nursery on the MSU campus where we could backcross our most promising F1 lines with the original disease-resistant parent lines and produce seed for future testing.  After preparing the 8000 sq. ft. plot area and installing drip irrigation, 729 clones representing the two parent lines and our most promising progeny lines were planted in the nursery.  Each year the nursery is hand weeded and sprayed with appropriate herbicides on a regular basis.  Plants are fertilized as needed to maintain vigor.  During the spring and early summer, the plants in the nursery cross with each other and set seed.  By July, the plants produce seed which is hand-harvested by a crew of 4-6 workers over a period of approximately two weeks.  This back-crossed F1 seed is used to establish sod for annual field testing and evaluation of the progeny. 

Corporate Partner Cooperative Research, 2005-2006
Following the 2005 nursery seed harvest, the seed was hand-threshed and cleaned during the fall of 2005 and used to create sods in the greenhouse during the winter of 2005-06.  This sod was transplanted to a putting green and a fairway on the Hancock Turfgrass Research Center in late 2006.  This MSU back-crossed sod was evaluated regularly and compared to the corporate back-crossed F1 sod that had been established on the Turf Center in 2005.  The data from these studies suggest that the MSU-generated F1 back-crossed seed has a higher level of disease resistance than the corporate seed.  Based on several year’s data, the disease resistance in our lines exceeds the level of resistance in any resistant commercial variety.

DNA Fingerprinting
During the spring of 2006, the MSU Genomics Technology Support Facility notified us that they were unable to genetically distinguish between our bentgrass lines and other bentgrass cultivars based on current technology.  Therefore, no AFLP fingerprints were obtained.

Field Research for 2007
Our field efforts over the next year will center on continued maintenance of our nursery, on-going evaluation of MSU and corporate-generated F1 back-crossed sods on the Turf Center.  We are currently in discussions with our corporate partner regarding joint research projects that they may want to conduct during the next year, possibly utilizing additional MSU germ plasm and/or seed.

Genetic Research for 2006-2007
While generating specific genetic fingerprints for our MSU lines appears to be unrealistic at this time, we do plan to investigate the genetic basis for the disease resistance expressed in our lines.  This will be a multi-year, joint project between MSU, USDA, and possibly other universities which will help us to understand whether the resistance that is expressed in our material is genetically similar to that expressed in other university’s resistant germ plasm.  In order to do this, the initial steps toward development of a linkage map, which correlates a specific DNA marker with a resistance trait, will be initiated.  This will provide a basis for comparison of MSU germ plasm with that from other universities to ensure that our resistance trait is novel.  This process is highly labor-intensive and will likely involve many seeding/screening cycles over an extended period of time.  This may establish a basis for intellectual property protection.

In this proposal we are seeking support for the continued screening and field testing of in-house and corporate-generated progeny.  In addition, these funds will be used to produce the 150-180 progeny that will be screened and used in the initial steps in the development of a segregating population for use in creating a linkage map.  This is the fourth year of a multi-year project with a long term goal of cultivar release in 5-8 years. 

Objectives

Short term (1 year):

• Initiate development of a segregating population by making crosses between resistant and susceptible, vegetatively propagated plants. 
• Field-testing of MSU-generated F1 progeny and other corporate-generated backcrossed disease-resistant progeny. (Completed in year 3, continuing in year 4).

Long term (5-7 years):

• Release of a disease-resistant bentgrass cultivar for commercial use.

Archived Proposals

2006 Disease Resistant Bentgrass Proposal 

2007 Disease Resistant Bentgrass Proposal 

Dr. Joe Vargas PCNB support letter

September 7, 2006

Public Information and Records Integrity Branch
Office of Pesticide Programs
Environmental Protection Agency
1200 Pennsylvania Ave., NW
Washington, DC 20460-0001
Attention: Docket ID No. OPP-2004-0202

A. Identity of Commenter

J. M. Vargas Jr. PhD, Professor of Plant Pathology, submits these comments in response to the Benefits and Cost Analysis of PCNB and Alternatives for Use on Golf Course Turf (Greens, Tees, and Fairways). 

I have been a member of the faculty at Michigan State University for the past 37 years.  I have conducted snow mold fungicide trials every year since I first arrived in November of 1968.  I have published the most widely used turfgrass disease text in titled “Management of Turfgrass Diseases Third Edition”.

B. Comments

Snow mold is a combination of two diseases, Typhula blight (cause by Typhula incarnata and Typhula ishikariensis) and Microdochium patch (caused by Microdochium nivale).  The percentage of each fungus contributes to a snow mold outbreak varies from year to year. The only cost effective control for snow mold on golf course fairways in areas where permanent snow covers the ground for 3 or more months is PCNB. 

Table 1 is based on studies conducted by Dr. Schmann in Massachusetts where snow cover and thawing occurs throughout the winter period. These data are not really relevant for regions that have permanent snow cover for 3 or more months The other most cited reference in the report is from Kentucky where severe snow mold outbreaks do not occur. Some of those cost effective combination alternatives may work well in Kentucky or Massachusetts, but they will not work in Northern Michigan or similar regions where snow covers the ground for three or more months.

In Table 3 of the report cost comparisons of fungicide combinations with and without PCNB are valid, but these combinations are used almost exclusively on greens and occasionally tees.  They are not used on fairway because of the costs involved, or in some cases lack of snow mold control. I know of no golf course in Northern Michigan that uses anything other than PCNB for the control of snow mold on fairways. 

Another problem with the suggested alternatives is the EPA-imposed restrictions on the total poundage of certain fungicides that can be applied in any one season, or the limited number of applications that can be made in a given season. In the sighted study, 12 of the 26 combination products contain chlorothalonil and 8 of the 18 combinations without PCNB contain chlorothalonil. Also, in my snow mold studies conducted in Northern Michigan chlorothalonil is an important partner in any fungicide combinations especially when PCNB is not included.

Chlorothalonil has an annual poundage restriction for greens, tees, and fairways which is normally reach before it is time for snow mold fungicide application to be made. One of the reasons for chlorothalonil usage during the growing season is fungicide resistance management. Most of the resistance problems on golf courses have occurred to the dollar spot organism.  Chlorothalonil is an important rotational partner in delaying resistance and, once resistance has occurred, it becomes the most economical way of managing dollar spot. It doesn’t take long to use up the allotted amount of chlorothalonil way before snow mold fungicide applications are to be made.

PCNB is the most economical means of controlling snow mold on golf course fairways. If it is removed from the market place, most golf courses will not be able to afford to apply the three way combinations necessary to obtain adequate disease control in climates like Northern Michigan. It will be especially devastating to golf courses that have predominately creeping bentgrass fairways where the primary disease is dollar spot during the summer. If the snow mold kills the creeping bentgrass, it will be replaced by annual bluegrass which will then require multiple fungicide applications of various fungicides for not only dollar spot but anthracnose and summer patch as well.