Vineyard and Winery Information Series:
Vol. 20 No. 1, January-February 2005
Dr. Tony K. Wolf, Viticulture Extension Specialist
Return to Table of Contents
Inter-row cover crops, such as perennial grass, have been a traditional means of vineyard floor management in Virginia vineyards. The grass provides an effective means of minimizing soil erosion and it allows equipment movement in the vineyard shortly after rains. Sod also reduces soil heating, dust, and moncultures of grass may reduce the populations of certain vineyard pests, such as dagger nematodes. The sward also requires mowing at times; particularly when we wish to reduce the competition with vines for water resources. The inter-row sward of grass is typically used in tandem with 3- to 4-foot wide weed-free strips under the trellis. Some of the conventional reasons for maintaining the weed-free strips are to minimize sod's competition with vines for water and nutrients, to reduce the survival rate of grape root borers at the point the emerging larvae enter the soil, and to reduce the abundance of climbing cutworms that find refuge in grass and other litter near the base of vines. The annual hilling and de-hilling of graft unions in areas subject to winter cold injury also precludes perennial under-trellis vegetation.
There is interest in extending the traditional inter-row cover crops under the trellis. In situations where vine size and vigor are excessive, the under-trellis cover crops might effectively be used to reduce vegetative growth, thereby reducing the need for some of the labor-intensive canopy management. The goal is to achieve a more desirable vine balance. "Balance" can be quantitatively expressed as cropload (e.g., 5 to 7 kilograms of crop per kilogram of pruned canes) or as leaf area to crop ratios. For the latter, balance is a steady-state condition at veraison when vines have 1.2 to 1.5 m2 of healthy, exposed leaf area for each kilogram of crop. The definition implies that the vineyardist need not trim shoots or remove lateral shoots to obtain balance. There is an abundance of literature that illustrates the effect of cover crops in general on reduced vine vigor and vine size, although much of this work deals with inter-row swards in a more arid environment.
What are the downsides to maintaining a perennial or even an annual under-trellis cover crop? The chief concern would be an excessive competition with the vines for water and nutrients (this is also covered in the literature). We need only think of the dry 2002 season to recognize that "too much of a good thing" may be bad. Growers who choose to try under-trellis cover crops will need to stay on top of vine water management and be prepared to irrigate and/or to suppress the growth of cover crops in situations of excessive moisture deficits. Severe water stress, depending upon timing, can reduce fruit set, reduce fruitfulness in the following year, impair juice and wine quality, lead to sunburning of fruit, reduce the rate and extent of cold acclimation, and the stress can reduce vine size more than desired. Under-trellis vegetation may also affect the ecology of the vineyard in ways that are not entirely desirable (or predictable). Increasing the diversity of vegetation in the vineyard through the cultivation of a variety of flowering plants either in the row middles or under the trellis on face value seems like a good idea. But I suspect that the increased plant diversity may also increase the diversity of potential vine pests. We did not have problems with grapevine yellows (GY) in our Chardonnay at Winchester until 2004, the year following our initial trials with under-trellis vegetation. This is entirely anecdotal, and there might be other factors, such as the abundant moisture, that contributed to the appearance of GY disease in 2004. The point, however, is that changing the vineyard floor management may alter the insect and other pest ecology of the vineyard in ways that we did not foresee.
We are interested in exploring the use of under-trellis cover crops as a means of regulating vine vigor and components of yield, while attempting to understand the potential negative consequences of this management practice. Our interest was stimulated by the very wet 2003 and 2004 seasons, and the discussions that occurred during and following the "Grapes, Wine and Environment" Symposium held in Roanoke in July 2004. We have intentionally sown grass (oats) under the trellis and we have allowed crabgrass to colonize the under-trellis strip of mature vines during the past two wet seasons. The effects on old (14-year-old), deeply rooted, high-capacity vines were non-apparent in those wet seasons, perhaps because the vines' root systems were extensive (at least 1.5 m of rooting depth in a Frederick-Poplimento clay loam with > 130 mm of moisture per m of soil). We have proposed research that will evaluate the combination of under-trellis cover crops, use of size-restricting rootstocks, and two other means of root volume manipulation: one consisting of root growth restriction, the other consisting of fairly severe root pruning. We feel that the combination of factors may be necessary in some cases to have any impact on vine growth, especially where older vines are deeply rooted in soils that have large volumes of plant-available water. It would be nice to have vineyards sited on rocky or gravelly soils that had low volumes of nutrients and water. But until those sites are found in appropriate mesoclimates, we need to explore other means of limiting the vine's ability to exploit soil resources.
Return to Table of Contents
Fritz was introduced at the recent Virginia Vineyards Association Annual Technical Meeting in Richmond, and I've asked Fritz to introduce himself in this newsletter in his own words.
FW: I am very pleased to introduce myself as Viticulture Research-Extension Assistant to the grape and wine industry of Virginia. As a native of Pennsylvania, I am well aware of the viticultural potential that exists in the Eastern US for fine wines. As a researcher in the vineyards of this region I am also aware of the many challenges we face in this climate and the need for research and education that will serve the needs of the grape and wine community.
My interest in viticulture and wine developed during the past five years from activities in viticulture research and industry experiences in grape growing and wine making. My first experience in the grape industry began in 1999 as a vineyard worker for the Chaddsford Winery in southeastern Pennsylvania while I was obtaining my Bachelors of Science degree in Horticulture from Penn State University. Subsequently, in the summer of 2001, I had the opportunity to manage the Penn State research vineyard while initiating grapevine decline research in Pennsylvania and New York vineyards. I remained at Penn State to obtain my Master of Science degree from the Department of Plant Pathology under the advisory of Dr. Jim Travis working in various projects concerning grapevine decline, disease management, and the use of compost in vineyards. My MS thesis addressed the factors contributing to declining grapevine replants in established vineyards and included an evaluation of the effects of compost on young vine growth. After the completion of my MS degree I migrated to the province of Pisa, Italy for an industry training period in which I served as an assistant winemaker for the 2004 harvest at Caiarossa Vineyards and Winery.
The decision to advance my career in the Virginia industry was encouraged by communication with the enthusiastic viticulture community in the eastern US. Many growers have expressed a need for individuals with experience in soil and plant sciences in this region. I am enthusiastic about using my background to conduct field research that will provide direct results for the local viticulture community. I look forward to visiting your sites and working in Virginia under the direction of Dr. Tony Wolf and the grape and wine community.
Return to Table of Contents
Dr. Leavitt collected numerous, suspect trunk and cordon samples in his visit here in May 2003 and recently shared some results of the fungal isolation and identification of those samples. The following is an edited version of a report that Dr. Leavitt, and his fellow researchers shared with us on his survey findings from Virginia, Maryland and New York State.
Canker Diseases of the Vine
George Leavitt1 , Jose Urbez2, and W. D. Gubler3
1 Viticulture Farm Advisor, University of California Cooperative Extension, 328 Madera Ave. Madera, CA 93736. firstname.lastname@example.org - (559) 675-7870 x 206. 2 Post-Graduate Researcher, 3 Extension Specialist Department of Plant Pathology UC Davis, Davis, CA. 93618. email@example.com , firstname.lastname@example.org - (530) 752-4982.
Early investigations into the cause of dead-arm disease of grape ultimately led researchers to confuse the symptoms and etiology of Phomopsis viticola (formerly called dead-arm) and Eutypa lata (Eutypa dieback). Eventually the cause of the cane lesions, leaf spotting and berry infections were attributed to Phomopsis while the typical wedge shaped trunk cankers and the stunted chlorotic spring growth were ascribed to Eutypa. Worldwide reports of the affiliation of Eutypa with pruning wounds and trunk cankers soon followed.
Subsequent field work in the mid 1980's in vineyards in the southern San Joaquin and Coachella valleys of California resulted in the discovery of many wedge shaped cankers on vines which failed to show the typical stunted chlorotic spring growth attributed to infection by Eutypa nor was the fungus isolated from the cankers. Further research led to the identification of Botryosphaeria rhodina (Botryodiplodia theobromae) as a cause of cankers on grapes in these areas of California. The worldwide pathogenicity of all three fungi has been well established.
The symptoms of the two major canker fungi are as follows:
|Eutypa lata:||Botryosphaeria rhodina:|
With the above symptoms it is easy to understand how these two fungi were confused for many years as the wedge shaped cankers caused by Botryosphaeria rhodina are indistinguishable from those originated by Eutypa. The best distinguishing characteristic is the absence or presence of the stunted chlorotic spring growth typical of infections by Eutypa.
Both fungi can cause cankers and mixed infections have been found on vines. Canker developement of both fungi is always towards the base of the vine from the point of infection. Besides lengthening, the cankers also grow in a lateral direction in the arms, cordons and trunks of the vines for several years until only a small wedge is alive. Death of the vine part occurs when the remaining live wedge is killed by the growth of the fungus.
Many different Botryosphaeria species have been found and isolated from wedge-shape cankers on grape in India, Egypt, Mexico, South Africa, Venezuela, Brazil and in the U.S.A. (California, Arizona and New York).
Recent (2003-04) isolations from cankers found on grapes in the Northeast (New York, Pennsylvania, Maryland and Virginia) and throughout California have consistently yielded several different Botryosphaeria species and, in lesser amounts, Eutypa and Phomopsis.
Like California, there appears to be more than one fungus causing canker diseases of the vine in the Northeast. Eutypa dieback has been previously identified and confirmed as one of those fungi, but often cankers are evident where Eutypa cannot be isolated or identified. Work performed by Leavitt at the New York State Agricultural Experimental Station in Geneva, New York, in the summer of 1998, isolated another fungi, similar to B. rhodina, from cankers of grapevines but it was not identified to species at that time. More canker sampling was performed in May 2003 from vineyards in New York, Pennsylvania, Virginia, and Maryland. The fungi recovered that appeared to be Botryosphaeria were divided into three groups based on spore (if present), colony morphology and molecular work. Seven of the Botryosphaeria isolates were identified to three different species: five were B. parva, one was B. obtusa, and one isolate was B. dothidia. The other isolates appear to be B. parva but this was only based on colony morphology. All three of these species have also been isolated from grapes in Northern California. All isolates are available upon request from Jose Urbez at U C Davis.
Further work needs to be performed in the California and the Northeast grapevine areas to determine if other species are present and whether they are indeed pathogenic on grape. The tables below summarize the vineyards and varieties sampled in May 2003 and the results of the molecular (PCR) work.
Pruning is a terrible thing to do to a grapevine. While it may be defined as a proper and necessary cultural practice, the wounds created have far reaching consequences. Pruning wounds offer easy access into the vine by several pathogens. Eutypa and Botryosphaeria are two which have been positively identified to infect vines in this fashion. Phomopsis may also be a contributor to this problem on highly susceptible varieties. There is a good possibility that the fungi isolated in the Northeast may act in the same manner. Whatever the cause, the economic necessity of controlling the canker-causing fungi is vital to the long term health, vigor and production capacity of the vine. The use of fungicide pruning wound paints will aid in preventing the entry of these fungi into the vine framework. While several fungicides have been shown effective, only Topsin is registered for use as a pruning wound paint in California. When used as a preventive it is an effective but laborious method of maintaining vine health.
While pruning wound paints may be effective, being chemically based they may not offer true long term protection. Healing of pruning wounds in California varies from 4-6 weeks in the middle of winter to 10 days in late winter/early spring. Currently registered chemicals for pruning wound protection may not be effective for the 4-6 week period needed. Editor's note - some pruning protection measures were cited in the Nov-Dec 2003 Viticulture Notes.
Unilateral or bilateral cordon training favors disease development on grapevines. Once entry into the vine was accomplished the cordon training system enables the cankers to remain on the vines for long periods of time to lengthen, enlarge and eventually kill spurs, arms, cordons and even vines. Observations in New York and Australia where multiple trunk trained vineyards allow removal of the older wood and re-training of new trunks has indicated much fewer incidences of cankers. Older trunks, which probably contain the most and largest cankers, are constantly removed from the vine.
Vigorous vines appear to survive for long periods with numerous cankers. However, as spurs and arms die, the fruiting capacity of the vine becomes more limited each year and overall vineyard production declines. The production capacity of a vineyard can be sustained for a lengthy period of time despite numerous cankers if a good retraining program is instituted and vine vigor is maintained. This is often achieved by leaving 2-3 new spurs on vigorous arms and replacing cordons and vines as necessary to restore the fruiting capacity of the vineyard. Care should be taken when instituting deficit irrigation schedules not to overstress vineyards as vine vigor is an important part of canker management.
Virginia and Maryland survey results
|Vineyard||Variety||Sample #||Bot Recoveries||PCR Results|
|Virginia||Seyval Blanc||53-57||1||#53 - B. dothidia|
|Virginia||Chardonnay||58-61||2||#58 - B. parva|
|Maryland||Mix of two vineyards||62-67||1||Not Determined-appears like B. parva|
|Virginia||Chardonnay||74-78||1||# 74 - B. parva|
New York Grape Samples.
|Variety||Sample #||Bot Recoveries||PCR Results|
|Catawba||138-147||3||#143 - B. parva|
|?||161-169||4||# 163 & 165 - B. parva|
|?||170-177||3||# 170 - B. obtusa|
|Chancellor||178-189||1||# 186 - B. parva|
Return to Table of Contents
A one-day conference of rural innovation to showcase ideas, projects, and programs that enhance agriculture and rural business will be held on March 18, 2005 at the Lee-Jackson Best Western Conference Center in Winchester, Virginia. The conference will begin at 9:00 am and conclude at 3:00 pm. The conference is being planned to provide farmers, landowners, and rural businesses an opportunity to see and hear industry leaders discuss innovative practices and methods for agriculture development.
The forum will feature a series of presentations, with an emphasis on farming for high-profitability by using innovative and sound business approaches particularly suited to the Mid-Atlantic region. Topics have been chosen to address innovative changes needed for farming and rural businesses, and will feature progressive speakers recognized for their expertise in innovation transition.
Forum topics will include:
In addition, exhibits by agricultural suppliers, businesses, and support agencies will be featured the entire day. Area agricultural businesses are encouraged to participate with exhibits and displays.
A registration fee of $25.00 per person will include the forum program, morning refreshments, and lunch. Registration information is available on-line at www.LoudounFarms.org or by calling 703-777-0426. Pre-registration by March 9th is required.
The Forum for Rural Innovation is a cooperative educational effort by the offices of Cooperative Extension and Agricultural Economic Development in Loudoun, Fauquier, Clarke, and Frederick counties of Virginia, and Jefferson County, West Virginia, and the Potomac Headwaters RC&D.
B. New grower workshop at 2005 Wineries Unlimited (24 March 2005)
Dr. Tony Wolf (VA Tech), Dr. Joe Fiola (U of MD) and Mark Chien (Penn State) will team-teach a one-day workshop for people who are interested in starting a commercial vineyard in the Mid-Atlantic region. The workshop will provide Sa general overview of all aspects of vineyard development from pre plant decisions such as site selection, variety and rootstock choice, vineyard economics, equipment and supplies, through vineyard care up to the third year including training, pruning, disease and pest control, vine nutrition, weed control and more. The focus is on practical information that will give the prospective or beginner grower a foundation of knowledge needed to start a successful vineyard. Plenty of handouts and information resources are given out and a field trip to a nearby vineyard is included. Lunch and snacks are included in the registration fee. For the second year, the workshop will be a part of Wineries Unlimited, the large trade show and winery/vineyard meeting sponsored by Vineyard and Winery Management and held at the Lancaster Host Resort in Lancaster, PA. The date for the workshop is Thursday, March 24 from 8 a.m. to 5 p.m. Wineries Unlimited is the perfect complement to this class. It provides people who are exploring the idea of starting a vineyard or have just recently planted one to meet with others who share a passion for growing wine. It's also a great opportunity to visit the largest vineyard equipment and supply trade show outside of California. The WU program contains dozens of seminars in viticulture, wine making and wine marketing. Even if you are just a beginner, or haven't yet planted your first vine, this can be a valuable meeting to attend along with the new grower workshop. You can find information and registration about Wineries Unlimited at www.vwm-online.com/. Register for the New Grower Workshop directly with Penn State Cooperative Extension. You will be able to find more information about the meeting at the Wine Grape Network website at http://winegrape.cas.psu.edu/. If you have any questions, please call Mark Chien at 717.394.6851 or email@example.com.
Thursday, March 24, 2005
8 a.m. to 5 p.m.
Lancaster Host Resort, Lancaster, PA
Pre-registration required. Class size is limited, so please register early.
If you have just started or are thinking about growing wine grapes this workshop will give you a basic overview of everything that is involved with developing a vineyard through the second year. It will provide you with a foundation of knowledge so you can answer the endless questions that you will have before you plant your first vine. It is also a good review course for the beginner grower. Its proximity with Wineries Unlimited offers students a unique chance to attend additional seminars as well as look at equipment and supplies at the trade show.
OTHER MEETINGS OF INTEREST IN THE REGION
17 How to Develop a High Quality Wine Vineyard at the Historic Hopewell Vineyard near Oxford in Chester County, PA. Hosts are Tony and Karen Mangus. 9 - 5. Growers will teach other growers the secrets of planning, planting and developing a top quality wine vineyard at this full day workshop. The emphasis will be on the practical, how-to aspects of vineyard development including methods and materials. Pre-registration required. Cost is $50 and includes lunch and handouts. For information and registration, call Mark Chien.
20-22 Ohio Grape and Wine Short Course at Geneva-on-the-Lake in Ohio is a comprehensive workshop on viticulture and enology with marketing, wine tastings and special events. Dr. Paul Skinner from Terra Spase in Napa Valley will talk about vineyard soils. There will be a special workshop for new growers held on February 20. For more information, visit the Ohio Wine Producers web site at http://www.ohiowines.org/ or contact Dr. Imed Dami at OSU at (330) 263-3882.
3/4 Michigan Wine Industry Annual Meeting at the Crystal Mountain Resort in Thompsonville. More details at http://www.michiganwines.com/index.html.
4/5 Finger Lakes Grape Growers Convention and Trade Show at the Holiday Inn in Waterloo, NY. Many topics in wine grape production include research and grower presentations. Trade show. For more information, call 315.536.5134 or visit www.cce.cornell.edu/programs/finger-lakes-grape/.
5 Maryland Grape Growers' Association Annual Meeting at the Howard County Fairgrounds. An all day program focusing on viticulture topics relevant to Maryland and Mid-Atlantic growers. Visit www.marylandwine.com/mgga/ or contact Bob White at 410.374.3227 for information.
19 Grape Expectations at the Forsgate Country Club in Jamesburg, NJ. 8:30 a.m. to 5 p.m. is a day long symposium of viticulture, enology and marketing presentations designed to present new and relevant information for professionals and amateurs involved in wine production. Mr. Kevin Chambers, owner of Oregon Vineyard Supply and a grower in Oregon is the invited speaker. Fee is $75 and includes a tasting of NJ wines. For information, please contact Dr. Gary Pavlis at 609.625.0056.
21-24 Wineries Unlimited. Host Resort. Lancaster, PA. Sponsored by Vineyard and Winery Management. Program features a wide variety of topics on viticulture, enology and wine marketing. A large trade show accompanies the meeting. For more program, information and registration, visit www.vwm-online.com/
24 New Grape Grower Workshop in association with Wineries Unlimited. Host Resort. Lancaster, PA. 8 a.m. to 5 p.m. This intensive, full-day overview is directed at people who have just started a vineyard or plan to start a commercial vineyard in the Mid-Atlantic regions. It is team taught by Dr. Tony Wolf (VA Tech), Dr. Joe Fiola (U Md) and Mark Chien (Penn State). It covers all topics associated with developing and operating a commercial vineyard including site selection, grape market, vineyard economics, equipment and supplies, site preparation, varieties and rootstocks, trellis systems, disease, pest and weed control and management into the first year. Registration fee is $125 and includes lunch, breaks and handouts. Register through Penn State Coop Ext. Contact Mark Chien at 717.394.6851 for more information and registration.
24 Lake Erie Grape Growers Conference in at the SUNY campus in Fredonia, NY sponsored by Cornell and Penn State. A full-day meeting with breakout sessions on a variety of viticulture, marketing, juice and wine topics. A trade show accompanies the meeting. Check http://lenewa.netsync.net/public/lergphom.htm.
5 Team Wine Growing: Working Together in the Vineyard and Winery. Location TBA, SE PA. 8 a.m. to 5 p.m. The focus of this meeting will be wine production in the vineyard and cellar and planning for the upcoming season as a wine growing team. Includes pruning strategies and managing yields for quality, effects of disease on wine quality, planning for wine capacity, quality and production, variety and clone choice as they relate to wine blending. Registration fee of $75 includes lunch and handouts. Instructors are Mark Chien and Stephen Menke from Penn State Cooperative Extension with invited speakers. Contact Mark Chien at 717.394.6851.
6-8 34TH New York Wine Industry Workshop at the Lakefront Ramada in Geneva, NY. Annual enology learning event that features wine making sessions. For more information, go to www.nysaes.cornell.edu/fst/faculty/henick/wiw/.
25-27 Pennsylvania Wine Association and Pennsylvania Association of Winegrowers joint annual meetings at the Wyndham Hotel in Harrisburg, PA. For the first time, the two industry associations in Pennsylvania will hold their annual meetings jointly. Focus of vit/enol sessions will be on Pinot Gris and Vidal Blanc production in the vineyard and winery, also wine marketing topics will be covered. Pesticides credits will be available. Visit the PWA web site at www.pennsylvaniawines.com/.
6/7 Wine and Juice Analysis Workshop at FREC in Biglerville, PA - http://frec.cas.psu.edu/. See January 8 description. Sensory workshop and dinner on May 6 at Gibraltar (additional $50 fee). Hands-on teaching and demonstration at individual stations such as calibration of pH meters and solutions, VA, and other essential winery lab practices will be covered. Limited to 25 participants. Registration fee is $85. Contact Stephen Menke (717.334.6271).
Virginia summer vineyard meeting series with VA Tech extension and research personnel including tours of vineyards, current situation updates and specific viticulture topics. Look for designated sites and information in future updates of this calendar and on the VVA web site - www.virginiavineyardsassociation.com/.
11 Maryland Grape Growers' Association Summer Field Day at Copernica Vineyard in Carroll County. Practical viticulture information for Mid-Atlantic grape growers. Visit www.marylandwine.com/mgga/ or contact Bob White at 410.374.3227 for information.
20-24 American Society for Enology and Viticulture Annual Meeting in Seattle, WA. ASEV is the professional association for the industry. Presentations are mostly scientific in nature. A large trade show accompanies the meeting. A great place to network. Go to www.asev.org for more information.
26 Vineyard Management class at Linden Vineyards in Linden, VA. Wine grower Jim Law offers a series of excellent practical, commercial level and high quality workshops on a variety of grape growing and wine making topics. The focus of this session is the finer points of day to day management in a producing vineyard including canopy management, training, vine nutrition and pruning. Go to the Linden web site for information and registration www.lindenvineyards.com/.
13-15 American Society for Enology and Viticulture Eastern Section annual meeting and symposium at the Millenium Hotel in St. Louis, MO will feature a focus on the enology and viticulture of four groups of varieties of increasing importance in the Eastern US and Canada: Norton/Cynthiana, Traminette, Minnesota Varieties (Frontenac, LaCrosse, etc.), and Pinot Gris. Join a pre-conference tour of Missouri wineries on July 13. This meeting will also be coordinated with the International Grapevine Genomics Symposium, July 12 - 14. This Symposium is part of the Southwest Missouri State University (SMSU) Centennial Celebration and organized in cooperation with the International Grape Genome Project (IGGP). Visit http://www.nysaes.cornell.edu/fst/faculty/henick/asev/ for more information and registration.
5 or 12 Viticulture in-service for regional cooperative extension agents at the VA Tech Agriculture Research and Extension Center in Winchester, VA. A full day training workshop for ag agents interested in working with wine grapes. Contact Tony Wolf, Joe Fiola or Mark Chien for information. Open to extension agents in any state. Exact date and information TBA.
13/14 Winemaking Basics and Advanced Winemaking at Linden Vineyards in Linden, VA. Wine grower Jim Law offers a series of excellent practical, commercial level and high quality workshops on a variety of grape growing and wine making topics
Return to Table of Contents
"Viticulture Notes" is a bi-monthly newsletter issued by Dr. Tony K. Wolf, Viticulture Extension Specialist with Virginia Tech's Alson H. Smith, Agricultural Research and Extension Center in Winchester, Virginia. If you would like to receive "Viticulture Notes" as well as Dr. Bruce Zoecklein's "Vinter's Corner" by mail, contact Dr. Wolf at:
Dr. Tony K. Wolf
AHS Agricultural Research and Extension Center
595 Laurel Grove Road
Winchester, VA 22602
or e-mail: firstname.lastname@example.org
Commercial products are named in this publication for informational purposes only. Virginia Cooperative Extension, Virginia Tech, and Virginia State University do not endorse these products and do not intend discrimination against other products that also may be suitable.
Visit Virginia Cooperative Extension.
Visit Alson H. Smith, Jr., Agricultural Research and Extension Center.