Sustaining Grape Production in the Northeast through Farm-tested Information Technologies

Final Report for LNE96-072

Project Type: Research and Education
Funds awarded in 1996: $147,943.00
Projected End Date: 12/31/2001
Matching Non-Federal Funds: $74,872.00
Region: Northeast
State: Pennsylvania
Project Leader:
James Travis
Penn State University Fruit Research and Extension
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Project Information

Summary:

The primary goal of the VITIS expert system is to replace fungicides with knowledge. Fungicides are often not required if it can be demonstrated through consideration of all the factors that there is no disease risk. In addition, even when there is a disease risk there are options to select less harmful fungicides and/or reduce rates.

Objectives:

1. Utilize participatory grower organizations in the grape industry to develop and farm-test new information tools.
2. Evaluate the usefulness, reliability, cost and acceptance of weather information sources for grower use in sustainable vineyard management decision-making.
3. Incorporate sustainable vineyard management tools such as predictive pest models and site-specific weather information and forecasts into the VITIS expert system and evaluate their impact on decision-making in commercial vineyards.

Methods/Approach

Growers requested that VITIS be designed to include the most important disease management factors along with interpretation of the information in relation to vineyard disease risk so that they could utilize the information in making a disease management decision.
Meetings with Pennsylvania and New York growers, and extension personnel were held in groups and individually to provide feedback on VITIS format and operation. In addition, plant pathology specialists from Ohio, Michigan, New York, Pennsylvania and Canada were involved in the development and representation of the disease management logic in VITIS.

Results – Five Grower Priorities for VITIS Operation.

1. Windows Version of VITIS.
2. Incorporate Vineyard Description and Disease History in Decision Support. The only way to arrive at a site-specific disease management decision is to consider all relevant vineyard and disease factors which contribute to disease risk.
3. Predictive/Site-Specific Weather Input. The growers recognized the need to input observed and forecast weather.
4. VITIS: “Light� or “Full�. The growers felt it was important to have VITIS operate in 2 consultation modes; Light or Full. The Light mode satisfies the growers wish that VITIS should have the capability to be accessed and have available information presented within the “time it takes to drink a cup of coffee.� The Full access mode in VITIS allows these same functions to be performed but also provides access to additional information on grape disease cycles, management options and will explain the disease risk assessment considering specific vineyard circumstances and weather and disease factors.
5. VITIS Operation Manual. A manual was developed which provides a step-by-step description to the user on the operation of the VITIS expert system.
VITIS is designed to operate on a PC and to provide support to the grape grower in making site-specific decisions. The program is available on floppy disks, zip disks or CD.

Impacts and Potential Contributions

VITIS advises the replacement of fungicides with knowledge, warns of disease risk, and assists the grower in the wise use of a fungicide. The grower and VITIS form an integrated disease management team. One of the most common comments made by growers after using VITIS is that they eventually start to understand and anticipate the logic used by VITIS in making decisions. As this occurs they rely less on the logic provided in VITIS and more on their own logic.

Introduction:

The primary goal of VITIS is to replace fungicides with knowledge. Fungicides are often not required if it can be demonstrated through consideration of all the factors that there is no disease risk. In addition, even when there is a disease risk there are options to select less harmful fungicides and/or reduce rates. In addition to advising on the wise use of fungicides, VITIS has been programmed to make wise rate recommendations. The improper use of low rates or high rates of fungicide may select for fungicide resistance by the fungus and in the end require more fungicide use in the vineyard.

Project Objectives:

1. Utilize participatory grower organizations in the grape industry to develop and farm-test new information tools.

2. Evaluate the usefulness, reliability, cost and acceptance of weather information sources for grower use in sustainable vineyard management decision-making.

3. Incorporate sustainable vineyard management tools such as predictive pest models and site-specific weather information and forecasts into the VITIS expert system and evaluate their impact on decision-making in commercial vineyards.

Cooperators

Click linked name(s) to expand
  • Robert Seem

Research

Materials and methods:

The prototype of VITIS developed prior to this project was designed to provide growers with a specific disease management recommendation. In the process of meeting with growers to develop this project, growers requested that VITIS be redesigned to become a decision-support tool for growers. They were interested in having the most important disease management factors presented in VITIS along with interpretation of the information in relation to vineyard disease risk so that they could utilize the information themselves in making a disease management decision. VITIS no longer provides a specific recommendation but has been developed to assist growers in making the decision.

Meetings with Pennsylvania and New York growers, and extension personnel were held in groups and individually to provide feedback on VITIS format and operation. In addition, plant pathology specialists from Ohio, Michigan, New York, Pennsylvania and Canada were involved in the development and representation of the disease management logic in VITIS.

Five Grower Priorities for VITIS Operation:

1. Windows Version of VITIS. The initial grower meeting after funding brought the entire grower group together to discuss the project and the direction of VITIS development. Growers quickly observed that the program should be translated from a DOS to Windows format. This was a very necessary step but was also very time consuming. Although the details of the conversion will not be detailed in this report the program format and screen displays were completely rebuilt for Windows operation. It required the first year of the project to accomplish utilizing both specialist and programmer time inputs. The Windows version of VITIS will be discussed more fully in the results portion of this report. The conversion of VITIS to windows allowed more effective weather graphing and user interface capabilities within VITIS.

2. Incorporate Vineyard Description and Disease History in Decision Support. The only way to arrive at a site-specific disease management decision is to consider all relevant vineyard and disease factors which contribute to disease risk. Growers requested that these factors be included in the VITIS expert system. These factors have been included in VITIS. Their importance to grape disease management will be discussed in more detail in the results section of this report. Plant pathology specialists from eastern United States listed in the appendix of this report participated in the revision and development of disease management logic within VITIS over the course of the project.

3. Predictive/Site Specific Weather Input. The growers recognized the need to input observed weather from multiple sources into the VITIS expert system to utilize in daily decision-making. The growers also identified the need to develop a method to input hourly weather forecasts into VITIS to truly predict disease risk. In addition, they asked for site specific, predictive weather information. In most disease predictive models historical weather information is utilized to “predict� the current disease risk. Growers wanted truly predictive capability in the VITIS program that utilized future, 1 to 3 day, hourly-predicted weather parameters to predict disease risk over the next several days. In addition they wanted the predictive weather information to be specific for their own vineyards.

Ground station weather monitors provide current observed weather information from individual vineyard locations to the VITIS expert system. The VITIS expert system has also been programmed to accept weather inputs from the major ground station weather monitors (Sensor Field Monitor, Metos, Campbell Scientific, NE Weather Association and Watch Dog). The weather data keeping system within VITIS can be easily programmed to accept data from new weather information sources as they become available.

Site-Specific Weather Forecasts. A private company, SkyBit, Inc. worked with the principal investigators over a three-year period to develop and refine the input of hourly historical and predictive weather information into the VITIS expert system. Once the format and input parameters were developed the predictive weather inputs were evaluated at the field level for accuracy over a two-year period. Several revisions of the original predictive weather models were utilized to improve the final product. Site-specific weather predictive models utilize latitude, longitude and elevation to more specifically calculate site-specific weather information for each farm.

At the growers' request, VITIS was also developed to accept both ground station observed weather information and predictive site-specific weather information into the same weather-operating file. This capability allows the grower to utilize weather information that was recorded by a ground station monitor in his or her own vineyard but also to include site-specific predictive weather information that has been calculated for the site and transferred to the user by email. Weather data is entered into the grower’s PC based on the output method used by the ground station equipment. Predictive weather data is received and entered through email. Once the weather data is loaded into the grower’s computer it can be quickly loaded into the VITIS program where it is summarized and utilized in decision support. The use of this type of weather data in VITIS will be explained more fully in the discussion of results.

4. VITIS: “Light� or “Full�. The growers felt it was important to have VITIS operate in 2 consultation modes; Light or Full. The Light mode satisfies the growers wish that VITIS should have the capability to be accessed and have available information presented within the “time it takes to drink a cup of coffee�. This quick access feature within VITIS has been developed and allows growers to: (1) quickly get a summary of current site-specific observed and predicted weather parameters, (2) have the weather information interpreted through disease predictive models, (3) have VITIS calculate estimated disease risk if no action taken, and (4) consider management options. These tasks can be accomplished within the “time it takes to drink a cup of coffee�.

The Full access mode in VITIS allows these same functions to be performed but also provides access to additional information on grape disease cycles, management options and will explain the disease risk assessment considering specific vineyard circumstances and weather and disease factors.

5. VITIS Operation Manual. A manual was developed which provides a step-by-step description to the user on the operation of the VITIS expert system. Since VITIS is designed to operate on the growers own PC, it provides instruction in loading the program, setting-up, operating and solving problems growers may have in using the expert system.

Research results and discussion:

VITIS is designed to operate on a PC and to provide support to the grape grower in making site-specific decisions. The program is available on floppy disks, zip disks or CD.

The “Light� VITIS expert system. As stated previously, growers wished VITIS to be set-up in two operating modes Light and Full. The Light mode was designed for quick access and the Full mode was designed to give a “fuller� presentation of decision support information contained within VITIS. In the Light mode, the grower is given the opportunity to load current and predicted weather into VITIS without entering the Full portion of the program. Observed weather data is either measured from a ground station weather monitor or remotely sensed weather data received by the PC through email. The import weather function allows weather from 7 different types of weather acquisition systems to be loaded and translated into VITIS weather files. VITIS utilizes hourly weather inputs as a basis for daily weather summaries, pathogen life stage development, disease predictive models, and calculation of remaining fungicide residues since the last pesticide application. VITIS can accept both ground station and remotely sensed predicted weather information to be loaded into the same VITIS weather file providing the grower with on-site observed weather information as well as site-specific predictive weather information for a single site.

A quickly provided summary of the current weather, predicted weather and disease model output through color graphs can also be obtained through the Light access mode. In the Light mode, the user can change the current date and time within VITIS without changing the PC’s date and time. This provides the user the option of running “what-if� scenarios of future or even past disease events and to consider VITIS decision support outputs. At the Light input screen it is also possible for the user to run just the downy mildew model. This is a highly complex disease predictive model that was developed by Cornell University. It will be explained in more detail in the explanation of the Full expert system mode. From the Light mode the user can also switch to the Full access mode by selecting, “Specific Vineyard Recommendation� or the user may select “Quit� to exit the expert system.

There are two “grayed-out� buttons on the Light input screen, scan vineyard alerts and demonstration. These are ideas for future development of VITIS. Presently VITIS considers one vineyard management block at a time.

The “scan vineyard alerts� function will allow a grower to scan all the vineyard blocks entered into VITIS at once to determine which blocks may have immediate need of attention. This will save the grower time since the grower will not have to run each block individually through VITIS to determine its status or need for attention. Since VITIS models the vineyard, disease organisms, weather and the intervention of man it is a complex decision support program.

The “demonstration� button will link new users to a demonstration of the function and intended use of all parts of the VITIS expert system.

The “Full� VITIS Expert System. The Full VITIS expert system mode is accessed through the “Specific Vineyard Recommendation� selection of the Light input screen. The Full expert system utilizes more vineyard culture and disease information and accesses deeper logic to provide management options than utilized in the Light expert system. The first question asked of the user upon entering the Full expert system is, whether the user would like to load a profile or a weather file. These are time saving features which allow the grower to quickly load a large amount of information about the specific vineyard block in a very short period of time. The profile provides VITIS with vineyard specific information, most of which can be created and entered into VITIS during the off-season so that there is no need to re-enter the information each time VITIS is consulted.

The profile contains the following vineyard specific information:

1. Vineyard Location. Since VITIS has been developed to operate in managing diseases in Michigan, Ohio, Pennsylvania and New York it must know where the vineyard is located. Pesticide labels vary by state. VITIS adjusts the potential list of fungicides based on the state.

2. Vineyard Age. VITIS is designed to consider the management of disease in mature bearing vineyards.

3. Vineyard Use. The management of disease on processing verses wine or fresh grapes is very different due to the greater susceptibility and value of wine and fresh grapes.

4. Pruning Date. A critical piece of information in preventing Eutypa dieback on grapevines is pruning date since infection occurs through fresh pruning wounds. This model is under development but not yet functional.

5. Vineyard Infection Resistance. The gray mold fungus, Botrytis, has developed resistance to Rovral in some vineyards. VITIS will not recommend Rovral if Botrytis resistance is known to occur in a vineyard.

6. Phenology. Phenology is the developmental growth stage of the grape vine. It is used in many decision support functions in VITIS such as, initiation of disease risk for specific pathogens, host susceptibility, fungicide application limitations etc.

7. Downy Mildew Dates. The most complex model in VITIS is the downy mildew model. This model calculates risk of infection through modeling the incubation, sporulation and risk of infection on an hourly basis throughout the season. Budbreak and the 5 to 6 leaf stage dates are critical to accurate modeling of the disease.

8. Harvest Date. All fungicides have a “days-to-harvest� limitation. This is to prevent illegal residues from occurring on the fruit at harvest. VITIS “knows� the days-to-harvest� limitations of all the fungicide labeled for use on grapes and any differences that occur between the states in labeling. VITIS will not include any fungicide in its list of options that would violate the “days-to-harvest� limitations. The harvest date can be adjusted throughout the season as estimates change.

9. Pruning Method. Processing grapes are pruned by hand or mechanically. Mechanically pruned grapes have a much higher potential for disease development. VITIS adjusts its management strategies based on pruning method.

10. Disease History. The occurrence or absence of disease in a vineyard will determine the likelihood of additional disease development and the rigor of disease management tactics required. VITIS requests information on the occurrence of all the major fruit and foliar diseases of grapes for the past and current season.

11. Fungicides Sprayed. Past applications of fungicide will impact current disease development and future fungicide applications recommended.

12. Fungicide Application Date. VITIS calculates the potential activity of the fungicide since the last application date based on plant growth, weather conditions, disease risk factors and specific fungicide properties.

13. Grape Varieties. There is great variability of disease susceptibility between cultivars. VITIS has a rating of each cultivars susceptibility to each disease. One of the factors in determining disease risk is cultivar susceptibility.

VITIS utilizes all of this information and a few additional factors which are asked at the appropriate time to estimate disease risk for the vineyard. An example of an additional factor is the affect of berry moth damage on Botrytis infection. VITIS will automatically ask if berry moth damage exists in the vineyard as Botrytis risk increases near harvest. If berry moth damage has occurred on the berries, VITIS will increase the disease risk potential above the foundation risk level provided by all other factors. All possible vineyard, management, disease and weather factors are considered when assigning individual risk levels to the fruit and foliar diseases managed within VITIS.

Once the profile that was developed earlier has been loaded into VITIS the grower has the option of loading a weather file and acquiring the same weather summaries as described under the Light expert system. It is also possible to view, edit, graph, and print the weather files or the summary grapes.

Participation Summary

Education

Educational approach:

Manual. As one of the stated objectives of this grant, a manual, which takes the user through the operation of the VITIS expert system, has been developed. A copy of the manual is included with this report. Revisions to the manual will continue as growers identify areas for improvement.

Workshops. In addition, workshops will be provided to new users to provide them with training in the use of the expert system. These training workshops will begin with the Beta test group during the winter of 2001. There will be an initial training session in March and follow-up training in April and May. Feedback sessions will occur at the middle and end of the growing season.

Local User Groups. The growers cooperating in the Beta tests this season will be asked to form and coordinate local user groups in their area when VITIS is released in 2002. This will provide new users with the opportunity to interact with experienced users and other new users as they learn to fully utilize the VITIS expert system. The VITIS expert system is being presented at grower educational meetings this winter. Some of these meetings include the multi-state fruit meeting being held in Hershey, Pennsylvania in late January 2001, at the Partnerships for Sustaining California Agriculture: Profit, Environment, and Community conference to be held in Woodland, CA, in March 2001, and at smaller grower meetings held across the region.

No milestones

Project Outcomes

Impacts of Results/Outcomes

The current disease risk for the vineyard can be obtained by selecting individual diseases or “Query all Diseases� from the “diseases� menu. VITIS displays a graph of the potential disease level in two weeks if no action taken for the specific vineyard. Potential risk levels range none to high. This graph provides the grower with a summary of the current risk level of all the potential diseases. In many cases the disease risk is none so no disease management action is required.

VITIS has several potential impacts on disease management and fungicide use in vineyards.

Impact 1. VITIS advises the replacement of fungicides with knowledge. Without the careful consideration of vineyard, weather and disease factors a grower will often spray a fungicide to prevent the imagined threat of disease even if none exists.

Impact 2. VITIS warns of disease risk. If there is a potential for disease development then the grower is forewarned in time to take appropriate management actions to prevent disease build-up in the vineyard. If there is risk of disease development then the grower can be advised to the potential fungicides that may be used. There are many possible cultural strategies growers can use to limit disease. However, at this point during the season when a disease epidemic is predicted by VITIS a grower has few options but to rely on the use of a fungicide.

Impact 3. VITIS assists the grower in the wise use of a fungicide. Not every circumstance requires the most effective, most specific and often most expensive fungicide available. VITIS displays all possible fungicides that would be effective given the current disease risk of the vineyard. When a fungicide is selected the other fungicides on the list that have the same mode of action are deselected so that two materials that have the same mode-of-action on the same fungicide are not needlessly applied at the same time. VITIS lists only those fungicides that are effective in controlling the diseases at the current disease risk levels. Often less expensive fungicides like sulfur or copper can be utilized with very satisfactory results. It is also true however, that these same fungicides can be applied uselessly in the wrong situation with crop loss as a result. VITIS provides a list of the appropriate fungicides for the situation. The grower is free to select their fungicide of choice. Another risk in selecting a fungicide is that unless a very complete knowledge of the modes-of-action of the fungicides is present, multiple fungicides with the same mode of action may be chosen, wasting the duplicate material. In addition, since fungicides vary greatly in their ability to control specific diseases it is possible that important diseases will not be controlled even by a combination of fungicides. VITIS also directs the grower to combine fungicides as a fungicide resistance management strategy.

Impact 4. VITIS calculates the rates appropriate for the disease risk. A fourth impact occurs when the grower has made the fungicide selection, VITIS bases the rate calculation on disease risk factors and fungicide activity and longevity. Rates that are too low will not satisfactorily control the disease and may stimulate resistance development to the fungicide by the targeted fungus. Additionally, fungicide rates that are too high for the disease risk situation, wastes material and may needlessly put pressure on the fungal population to become resistance. Both low and high rates will result in additional fungicide applications to the vineyard.

Impact 5. The grower and VITIS form an integrated disease management team. One of the most common comments made by growers after using VITIS is that they eventually start to understand and anticipate the logic used by VITIS in making decisions. As this occurs they rely less on the logic provided in VITIS and more on their own logic and their own far more complex understanding of the situation than is provided in VITIS. The final end product is a grower who utilizes the computational strengths of a computer system to summarize weather data and run mathematical disease predictive models combined with their own understanding and logic in managing all aspects of a vineyard.

Economic Analysis

Weather Information Costs. General weather information is available to growers from several sources, radio, TV, newspaper and the web. However none of these sources of information can provide hourly, site-specific weather information that is needed by growers to make effective disease management decisions. Growers require hourly weather data that can be used in disease predictive models. The weather information must be specific to individual farms to provide the maximum benefit to the grower in decided if fungicide sprays are required. To address one of the objectives of this study, commercially available environmental monitoring equipment was evaluated for accuracy, dependability proficiency in putting the data into the VITIS expert system. In summary, the results of this study indicate that ground station weather monitors can be helpful to provide historical weather information. There are concerns over the accuracy of some of the commercially available units. An alternative source of weather information is remotely sensed weather information. Remotely sensed weather information is calculated for specific vineyard locations using satellite, radar and national weather service environmental data inputs. A private company SkyBit Inc. cooperated with project to develop and test remotely sensed weather information in VITIS and to evaluate its usefulness to growers. The weather information is much more useful for the growers to collect and input into VITIS and the accuracy of the information is comparable to a ground station unit placed in the vineyard.

Ground Station units cost about $1500 to $7000 to serve one site. They require about 3 hours of maintenance per week to operate, and collect data. These units are utilized by growers over a 7-month period during the growing season. The cost to the grower of operating a ground station environmental monitoring device is therefore after initial purchase, 3 hours/week X 30 weeks X $10/hour labor cost = $900/season.

Remotely Sensed SkyBit weather information is received through the Internet on a daily basis and is specific for the individual grower site. SkyBit weather information costs the grower $75/month. There is little additional labor required for SkyBit weather since it is placed directly from the Internet into VITIS. The cost for SkyBit weather to utilize in VITIS for the season is, $75/month for the SkyBit weather X 7 months = $525/season. SkyBit also provides 3-day hourly forecasts that can be utilized within the VITIS expert system, which is an additional benefit to the grower.

Combination of ground station and SkyBit forecast information can be combined in the same weather file within VITIS allowing the grower to utilize their own ground station recorded historical weather information and SkyBit weather forecasts for their site. Although VITIS has been designed to operate on either system used alone.

Fungicide Reduction Savings. VITIS can save the grower through reduced fungicide application. One of the chief problems faced by a grape grower is knowing when a wetting period is a risk for disease development and when disease risk is low requiring no fungicide application. VITIS provides estimates of disease risk for individual vineyards. This allows the grower to ignore wetting periods, which reduces fungicide application. When a grower is uncertain about a disease risk potential a fungicide is often applied to avoid crop loss.

If a grower saves only 2 fungicide applications per season the savings on a 50 acre vineyard would be: $50/A fungicide X 2 sprays X 50 acres = $5000/season. Two fungicide applications per season is a reasonable number to expect from research trial results and grower feedback.

Reduction in Crop Loss Due to Disease. Crop loss in grapes is not uncommon even when they are repeatedly sprayed with fungicides. Grape diseases are highly destructive to the fruit with diseases infecting both green and mature berries. Through the wise use of weather information, disease predictive models and vineyard susceptibility evaluations, VITIS has the potential to reduce crop loss in wine grapes by 10% per season. Processing grape losses are normally less but do occur. Both wine and processing grapes are valued at about $1000/acre. If one considers the average grape vineyard acreage to be 50acres then an estimate of savings due to reduced crop loss from the use of VITIS can be determined. 10% crop loss X $1000/acre crop value X 50 wine grape acres = $5000/season savings in reduced crop loss.

Potential Yearly Savings to a 50 acre Wine Grape Grower Using VITIS:
Cost of SkyBit weather information = $525 (-)
Two Fungicides sprays saved = $5000 (+)
Additional Crop (10% less loss due to disease) = $5000 (+)
Total dollar savings to the grower = $9475/50 acre grape vineyard/season.

“Peace-Of-Mind� Factor. An additional benefit to the grape grower is less tangible but perhaps most important. All the growers involved in this study have stated that spraying fungicides is the least rewarding aspect of growing grapes. They all agreed that they would not spray a fungicide if they could feel comfortable that disease would not destroy their crop if a fungicide blanket were not continually applied to the grapes. VITIS provides that “peace-of-mind�. VITIS considers all aspects of their vineyard and its current susceptibility to disease. It clearly displays disease risk for their vineyard utilizing current and predicted weather information and the best mathematically available disease predictive models. VITIS uses knowledge to replace fungicides and it does it in a way that the grower can be comfortable not applying a fungicide. The Additional “Peace-of-Mind� factor = Priceless.

Areas needing additional study

A decision support system for growers is only begun, it is never finished. The growers cooperating in this study have many more ideas that would make the VITIS expert system even more useful to them. Integrating record keeping systems, web delivery and continual updating, and economic cost estimates of disease management options are just a few of the suggested expansions of VITIS provided by growers. As the VITIS system becomes widely adopted by grape growers its function will be expanded as time and resources permit. New disease predictive models are continually being improved and will be incorporated into VITIS once they have been validated in vineyards. The developers of VITIS (grower cooperators and university specialists) have decided to field test VITIS one more season. Beta grower test groups will be formed in Pennsylvania and New York to test VITIS’ output recommendations due to the high-risk nature of diseases on grapes. VITIS is scheduled for commercial release in the year 2002.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.