Development of a low-cost vertical patternator, part II

Final Report for FNE12-749

Project Type: Farmer
Funds awarded in 2012: $6,940.00
Projected End Date: 12/31/2012
Region: Northeast
State: Pennsylvania
Project Leader:
R. Martin Keen
Landey Vineyards
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Project Information

Summary:

An agricultural airblast sprayer with improperly positioned or defective nozzles results in spray drift, poor pest control and inaccurate application. It has been estimated that only 55% of a pesticide spray may hit the target. Use of a spray patternator reveals where the spray is deposited and allows the farmer to adjust the sprayer to its maximum efficiency. A patternator helps increase the amount of spray that hits the target plant, thereby increasing efficiency and efficacy. Use of a patternator can reduce spray drift up to 90% and reduce pesticide use up to 20%. This project expanded on the patternators developed in FNE10-689 with another patternator design and attempted to determine which patternator gives results closest to actual spraying in a fruit crop. Based on the information from this project the SARE patternator gives a more accurate spray pattern determination, but this cannot be determined 100% because of spray overlap on the card patternator. The SARE patternator more closely mimics the actual results in a vineyard or orchard versus the modified Cornell patternator. The use of any patternator reduces costs and increase productivity from reduced pesticide use and better application.

Introduction:

I am a part-time farmer currently farming 5 acres with my brother. The land is rented from our mother’s estate. The total size of the present farm is only 7.8 acres, although it has been farmed by our family for seven generations. There is no house on the premises, only a 40′ by 60′ tobacco barn. My brother and I first planted wine grapes on the farm in 1974. Today a total of 4 acres is planted in wine grapes and includes the French hybrids: seyval, vidal and chambourcin and a European vinifera, pinot noir. The vidal was planted in 1976, chambourcin in 1980, seyval in 1984 and 1986 and pinot noir in 2007, 2008 and 2009. Vines are grown with unilateral or bilateral cordon training on the bottom wire. A standard three wire system with wires at 36, 54, and 72 inches is used as the trellis system for the French hybrids. A seven wire trellis system with movable catch wires is used for the pinot noir. The vines are trained using vertical shoot positioning. Vineyard spacing is 9 foot wide rows with 6 feet between the vines in the row. An area of approximately one half acre is used for the growing and production of grafted vines and other varieties. From 1989 until 2004 I also grew one half acre of saffron on the farm. Previously I was the only commercial grower of saffron in the United States. The saffron was harvested, dried, packaged and sold directly to retail outlets under the label of Greider’s Lancaster County Saffron. Since 2004 the saffron harvest has been dramatically reduced to the point we no longer have a sufficient quantity for sales. The farm is composed entirely of Duffield silt loam with a 0 to 3% slope on the top of a small hill. The location provides excellent air drainage with no frost pockets. The surrounding area is almost entirely in farmland and is located in an agricultural security area. There have been no changes in the operation since the initiation of the SARE project. The technical advisor for this project is Mark Chien of Pennsylvania State University . Since 1999, Mark has been the wine grape agent for Penn State Cooperative Extension. Currently he is serving all of Pennsylvania.

Background from 2010 SARE project The total cost of a vertical paper patternator that can be used with an airblast sprayer is just $45. A large advantage of the paper card patternator is its ability to be used with any type of sprayer not just an airblast. For a boom sprayer, the cost of the patternator would only be $34. The photographic printer paper patternator does have disadvantages. The extremely short time of collection can introduce variability. Multiple tests should be run to reduce the inherent variability from a short collection time. Another disadvantage is repeat coverage of the same area from various droplets. At a high level of spray coverage this is a serious problem with the paper cards. The paper patternator is very valuable because it reveals what actually hits the target. Cards are very accurate in determining the actual percent coverage, which correlates to coverage on plants. One of the original intentions of this project was to determine which patternator developed in 2010 gave the best representation of the spray pattern from an airblast sprayer. It was thought the paper card patternator would reveal whether the SARE or modified Cornell patternator gave results closest to the actual spray pattern. Once the paper card patternator was tested it was readily apparent the problem of spray overlap would make the determination of the best patternator design difficult. As spray coverage increases, spray overlap also increases, reducing the ability to determine the total output. Once a spray coverage of 100% is recorded, no additional spray will be recorded. Even at a spray coverage of 50% at least half of the spray will hit an area already covered. This effect reduces the total amount of spray output that can be recorded.

Based on the information from this project the SARE patternator gives a more accurate spray pattern determination, but this cannot be determined 100% because of spray overlap on the card patternator. The SARE patternator more closely mimics the actual results in a vineyard or orchard versus the modified Cornell patternator. The use of any patternator reduces costs and increase productivity from reduced pesticide use and better application. The patternators developed in FNE10-689 produced statistically significant differences in the spray patterns depending on the model tested. A new patternator design based on the use of photographic printer paper and a dye was tested and compared with the patternators developed in 2010. Photographic printer paper was also compared to water sensitive paper that has traditionally been used for determination of spray patterns. Image analysis software was developed as a part of the project so the results could be expressed quantitatively. The software (NESareScan) developed in this project for use with photographic printer paper was compared with the USDA DepositScan program that was developed for use with water sensitive paper and boom sprayers. In the 2010 project it could not be determined which design actually gives a more accurate representation of the true spray pattern generated by an airblast sprayer.

The current project attempted to answer that question and in the process develop an even lower cost patternator utilizing photographic printer paper and a dye. Spraying agricultural plants is a very complex problem. Some areas of the plant will receive a full dose of the spray while other areas may receive none at all and every possible permutation from full coverage to zero coverage can also be found on the plant. Each type of patternator has its own limitations. The patternators developed in 2010 collect spray material on numerous panels for a long period of time but some of the spray material is lost. The amount lost depends on the design. This loss reduces the accuracy of the patternator. While the paper patternators used in the 2012 project record all of the spray that hits the card, they have their own inaccuracies. An individual card is exposed to the spray for only fractions of a second. The short time of exposure can introduce inaccuracies. A high degree of variance can be found between some of the replicates. Also the cards cannot differentiate spray overlap. As the spray coverage on a card increases, the amount of spray that hits an area already covered by spray also increases. Of course the same overlap occurs on a plant.

In 2010 the right side of the airblast sprayer was used for all testing while in 2012 the left side was utilized. The SARE and modified Cornell patternator from 2010 were retested. The Cornell patternator captured 24% of the spray material while the SARE patternator captured 53%. The SARE patternator captured significantly (1% level of significance) more spray material on 5 of the 7 panels. The computer program developed for this project (NESareScan) measures droplet density, droplet size and percent coverage. Neither NESareScan or DepositScan gave accurate results for the droplet density with an airblast sprayer. Droplet size was difficult to measure because of droplet overlap and various droplet shapes created by the blast of high velocity air. The program determines the volume median diameter of the droplets or VMD. Volume median diameter is the most accurate at a very low percent coverage of 5% or less. The blue spray pattern indicator gave statistically smaller droplet sizes on the water sensitive paper. No statistical differences were found with the red food coloring. NESareScan gave smaller droplet sizes than the DepositScan program but the results were rarely significant. Percent coverage was the most accurate of the three parameters tested and it can be used to adjust the spray pattern. When using the blue spray pattern indicator and the NESareScan program the percent coverage means were higher and statistically significant with the gloss, semi-gloss and matte papers as compared to the water sensitive paper. There was almost no statistical significance with the DepositScan program. When using the red food coloring and determining percent coverage with NESareScan, only a few cards were statistically significant. More cards were statistically significant with the DepositScan program but no clear trends emerged.

Results from the first and second tests were used to compare the blue spray pattern indicator with the red food coloring. With both NESareScan and DepositScan programs the blue dye had statistically significant greater coverage than the red dye on all the photographic printer papers, but no significant difference with the water sensitive paper. The use of red food coloring will give a more accurate determination of the percent coverage. A comparison of the results from the NESareScan and DepositScan programs shows they are similar. Out of 168 statistical comparisons run between the NESareScan and DepositScan programs, 26 showed a statistical differences or 15.5% of the total. Of the 26 statistically significant differences, 19 times the NESareScan had a higher result and 7 times the DepositScan had a higher result.

Project Objectives:

An agricultural airblast sprayer with improperly positioned or defective nozzles results in spray drift, poor pest control and inaccurate application. It has been estimated that only 55% of a pesticide spray may hit the target. Use of a vertical spray patternator reveals where the spray is deposited and allows the farmer to adjust the sprayer to its maximum efficiency. A patternator helps increase the amount of spray that hits the target plant, thereby increasing efficiency and efficacy. Use of a patternator can reduce spray drift up to 90% and reduce pesticide use up to 20%. This project will expand on the patternators developed in FNE10-689 with another patternator design and determine which patternator gives results closest to actual spraying in a fruit crop.

The patternator design with the most accurate representation of the actual spray material deposited will help farmers be more efficient and economical in their pesticide spraying. The three patternators developed in FNE10-689 produced differences in the spray patterns depending on the model tested. Another patternator design, even lower in cost, will be tested and compared with the models previously built. The new patternator design will be based on the use of photographic paper and a dye. This patternator will require image analysis software for the results to be expressed quantitatively. The required software will be developed as a part of the project. Use of a patternator can reduce costs and increase productivity from reduced pesticide use and better application. The total cost of a vertical paper patternator that can be used with an airblast sprayer is just $45. A large advantage of the paper card patternator is its ability to be used with any type of sprayer not just an airblast. For a boom sprayer, the cost of the patternator would only be $34. The photographic printer paper patternator does have disadvantages. The extremely short time of collection can introduce variability. Multiple tests should be run to reduce the inherent variability from a short collection time. Another disadvantage is repeat coverage of the same area from various droplets. At a high level of spray coverage this is a serious problem with the paper cards. The paper patternator is very valuable because it reveals what actually hits the target. Cards are very accurate in determining the actual percent coverage, which correlates to coverage on plants.

One of the original intentions of this project was to determine which patternator developed in 2010 gave the best representation of the spray pattern from an airblast sprayer. It was thought the paper card patternator would reveal whether the SARE or modified Cornell patternator gave results closest to the actual spray pattern. Once the paper card patternator was tested it was readily apparent the problem of spray overlap would make the determination of the best patternator design difficult. As spray coverage increases, spray overlap also increases, reducing the ability to determine the total output. Once a spray coverage of 100% is recorded, no additional spray will be recorded. Even at a spray coverage of 50% at least half of the spray will hit an area already covered. This effect reduces the total amount of spray output that can be recorded. Based on the information from this project the SARE patternator gives a more accurate spray pattern determination, but this cannot be determined 100% because of spray overlap on the card patternator. The SARE patternator more closely mimics the actual results in a vineyard or orchard versus the modified Cornell patternator. The use of any patternator reduces costs and increase productivity from reduced pesticide use and better application. The patternators developed in FNE10-689 produced statistically significant differences in the spray patterns depending on the model tested. A new patternator design based on the use of photographic printer paper and a dye was tested and compared with the patternators developed in 2010.

Photographic printer paper was also compared to water sensitive paper that has traditionally been used for determination of spray patterns. Image analysis software was developed as a part of the project so the results could be expressed quantitatively. The software (NESareScan) developed in this project for use with photographic printer paper was compared with the USDA DepositScan program that was developed for use with water sensitive paper and boom sprayers. In the 2010 project it could not be determined which design actually gives a more accurate representation of the true spray pattern generated by an airblast sprayer. The current project attempted to answer that question and in the process develop an even lower cost patternator utilizing photographic printer paper and a dye. Spraying agricultural plants is a very complex problem. Some areas of the plant will receive a full dose of the spray while other areas may receive none at all and every possible permutation from full coverage to zero coverage can also be found on the plant. Each type of patternator has its own limitations. The patternators developed in 2010 collect spray material on numerous panels for a long period of time but some of the spray material is lost. The amount lost depends on the design. This loss reduces the accuracy of the patternator.

While the paper patternators used in the 2012 project record all of the spray that hits the card, they have their own inaccuracies. An individual card is exposed to the spray for only fractions of a second. The short time of exposure can introduce inaccuracies. A high degree of variance can be found between some of the replicates. Also the cards cannot differentiate spray overlap. As the spray coverage on a card increases, the amount of spray that hits an area already covered by spray also increases. Of course the same overlap occurs on a plant. In 2010 the right side of the airblast sprayer was used for all testing while in 2012 the left side was utilized. The SARE and modified Cornell patternator from 2010 were retested. The Cornell patternator captured 24% of the spray material while the SARE patternator captured 53%. The SARE patternator captured significantly (1% level of significance) more spray material on 5 of the 7 panels. The computer program developed for this project (NESareScan) measures droplet density, droplet size and percent coverage. Neither NESareScan or DepositScan gave accurate results for the droplet density with an airblast sprayer. Droplet size was difficult to measure because of droplet overlap and various droplet shapes created by the blast of high velocity air. The program determines the volume median diameter of the droplets or VMD. Volume median diameter is the most accurate at a very low percent coverage of 5% or less.

The blue spray pattern indicator gave statistically smaller droplet sizes on the water sensitive paper. No statistical differences were found with the red food coloring. NESareScan gave smaller droplet sizes than the DepositScan program but the results were rarely significant. Percent coverage was the most accurate of the three parameters tested and it can be used to adjust the spray pattern. When using the blue spray pattern indicator and the NESareScan program the percent coverage means were higher and statistically significant with the gloss, semi-gloss and matte papers as compared to the water sensitive paper.

There was almost no statistical significance with the DepositScan program. When using the red food coloring and determining percent coverage with NESareScan, only a few cards were statistically significant. More cards were statistically significant with the DepositScan program but no clear trends emerged. Results from the first and second tests were used to compare the blue spray pattern indicator with the red food coloring. With both NESareScan and DepositScan programs the blue dye had statistically significant greater coverage than the red dye on all the photographic printer papers, but no significant difference with the water sensitive paper. The use of red food coloring will give a more accurate determination of the percent coverage. A comparison of the results from the NESareScan and DepositScan programs shows they are similar. Out of 168 statistical comparisons run between the NESareScan and DepositScan programs, 26 showed a statistical differences or 15.5% of the total. Of the 26 statistically significant differences, 19 times the NESareScan had a higher result and 7 times the DepositScan had a higher result.

Cooperators

Click linked name(s) to expand
  • Mark Chien

Research

Materials and methods:

In the Northeast SARE Farmer Grant FNE10-689, the goal was to develop a patternator that had $100 or less in newly purchased material costs. Patternators were built and then tested for their ability to quantify the spray pattern of an airblast sprayer. A Cornell type patternator was also built to allow comparisons between the various designs. Spray patterns were collected in triplicate from each of the three patternators built for the project. The two SARE patternators developed for the project generated a different spray pattern that was statistically significant as compared to the standard Cornell type patternator. A question that could not be answered by the project was which design actually gives a more accurate representation of the true spray pattern generated by an airblast sprayer. This project attempted to answer that question and in the process develop an even lower cost patternator.

Water sensitive papers have been used to visualize the spray that is hitting a surface. These paper cards turn blue where they are exposed to water. Usually they are used by growers for a quick visual qualitative estimate of spray deposition. The cards must be handled with care because they are sensitive to moisture in the air, on the plant and on the hands. Water vapor from the plants can also cause the paper to turn blue. Water proof gloves must be worn when handling water sensitive paper. The cards are also fairly expensive and are made by Syngenta. Instead of using water sensitive cards, it has suggested that growers use high quality photographic printer paper and a dye in their spray tank to visually assess spray deposition. An exact protocol for this method or a means of interpreting the results has not been established. One of the goals of this project was to develop a low cost patternator utilizing cards or paper that more closely mimics what is actually happening when grapevines or other fruits are sprayed with an airblast sprayer. Various high quality photographic printer papers, water sensitive paper, and other papers were tested for their ability to accurately visualize spray patterns with a minimum of droplet spread. Most ordinary papers cannot be used because of droplets spreading in the paper due to wicking of the spray material through the fibers of the paper. This droplet spread would result in inflated values for the amount of spray coverage and droplet size.

The use of food coloring as a dye to visualize the spray pattern has been suggested. After checking the availability and pricing of several different colors of food dyes it was decided to use red food coloring in this project. Red food coloring also requires a lower concentration of dye to give readily apparent droplets on paper. Three different red food colorings were tested and the Shank’s and Butler’s brands gave the highest saturation of color for the least amount of dye. Shank’s and Butler’s are made by the same company and are available on the internet. Another dye tested was a blue spray pattern indicator, Terramark SPI. Blue dyes are commonly used in the lawn care and turf industries as spray pattern indicators. These dyes are available from pesticide wholesalers and retailers and on the internet. Only half the amount of blue turf indicator was required for good color intensity as compared to red food coloring. Blue turf spray indicators are designed to break down in sunlight after about two days. No discernible color change has been noted on the blue spray cards from this project even months after they were sprayed if stored properly. The cards were placed in plastic bags and not exposed to direct sunlight. Various high quality photographic printer papers and other papers were tested for their ability to accurately visualize spray patterns with a minimum of droplet spread. Initial testing was limited to using food coloring and the turf indicator diluted in water and a spray bottle.

White card stock, foam board and cash register tape were papers that had too high a droplet spread to accurately determine spray coverage. Greater droplet spread also meant the color intensity of the spots was reduced and would hinder computer recognition of droplets. Photographic printer papers were purchased from large chain office supply stores, OfficeMax and Staples. Generally the highest quality paper at the lowest price was selected. The higher quality papers are thicker and/or denser than lower quality paper. This would help reduce droplet spread. Staples Photo Supreme and OfficeMax Professional grade were initially tested. Both of these papers have a thickness of 10 mil. There appeared to be no difference in the quality of the papers. For the actual testing OfficeMax Professional grade matte, semi-gloss and glossy papers were selected, all with a thickness of 10 mil. Other photographic papers selected for field testing were Hewlett-Packard Premium matte (9 mil) and Hewlett-Packard Everyday glossy (8 mil).

The sprayer used in the project was adjusted before all testing and then never changed throughout the project. Our vineyard sprayer is a three point hitch Berthoud MGP 360 with torex nozzles purchased in 1975. The tractor utilized to operate the sprayer is an Oliver Super 55. The tractor PTO was set to 450 RPM using an ES 332 laser tachometer for all tests. At this RPM the sprayer pressure was set at 70 PSI. The nozzles utilized in the sprayer were Berthoud Saphirex 10 discs. The disc orifice diameter was checked with a digital caliper accurate to 0.0005 inches. The Berthoud Saphirex 10 discs had an orifice diameter of 0.033 inches. The Berthoud 360 MPG sprayer has a total of 10 nozzles with five on each side. When spraying in our vineyard, once the vines have reached the top wire at 6 feet, only three nozzles per side are opened. The top and bottom nozzles are not utilized. For all testing, the same setup was used. Only the nozzles on the left side of the sprayer were used during testing. The total output of each nozzle with Berthoud Saphirex 10 discs was measured using water with no additives. A plastic one gallon jug was placed over each nozzle and securely fastened. With the PTO running at 450 RPM, the spray was collected for one minute at 70 PSI. Knowing the total output of the sprayer will allow the determination of the percentage of total spray captured by the patternators. Four replicates were run and the amount of water collected was measured in milliliters. In order to compare the patternators developed in the 2010 NESARE project with the paper patternators in the 2012 project, the SARE and modified Cornell patternators from 2010 were retested. The amount of spray captured by the two patternators was measured using water with no additives. The mid-line of the sprayer was positioned 4.5 feet from the patternator surface. When spraying in our 9 foot wide rows, the mid line of the sprayer is 4.5 feet from the trellis on either side. The height of the sprayer remained constant through all testing. For each test the tractor was positioned with the sprayer nozzles in line with the leading edge of the patternator. This position maximized the collection of sprayer effluent. Tractor PTO was set at 450 RPM for all tests with an ES 332 laser tachometer. Sprayer nozzles were opened for one minute during each test.

Each patternator received a one minute trial run before any measurements were made. This trial run was made to insure all surfaces had been exposed to the spray and any water adhesion due to surface tension had occurred. With no trial run, the initial test would have slightly lower amounts of water collected in the containers. Four replicates were run for each patternator. Each paper patternator is constructed of an eight foot 2 X 4, a six foot metal pipe or T-post, push pins, rope or twine and photographic printer paper. With the dye the total cost of the paper patternator is about $44 to $45 dollars. A hole is drilled through wide face of the 2 X 4 about 3 feet from one end. The rope or twine is fed through the hole so the 2X4 can be secured to the pipe or post, which is driven about a foot into the ground. Water sensitive paper or cards of photographic printer paper are attached to the wide face of the 2X4 with push pins. A total of four paper patternators were constructed. The four paper patternators were placed about 24 feet apart in a straight line. Each patternator had one type of paper. Four different papers were tested in each test. A total of four replicates were done for each paper. With four different possible locations for a patternator during the testing, each type of paper was tested once at each of the four patternator locations. For testing the paper patternators, 10 gallons of water and the proper amount of dye was added to the sprayer’s tank. For proper color intensity 40 ml of the red food coloring per gallon of water was required. The blue turf spray pattern indicator required only 20 ml per gallon of water. The Berthoud 360 MPG has a 75 gallon tank. Tractor PTO was set at 450 RPM for all tests with an ES 332 laser tachometer. At this RPM the sprayer pressure was set at 70 PSI. The height of the sprayer above the ground remained constant through all testing and only the nozzles on the left side of the sprayer were utilized.

The tractor was started 50 feet before the first paper patternator in third gear and with the left side nozzles of the sprayer open. Testing was done on level ground at a constant speed of 2.68 miles per hour. The first test involved using the blue spray pattern indicator with various papers. One patternator used seven 4” x 6” cards of OfficeMax professional grade matte photo paper. The cards were arranged with the 6” side being vertical. Cards were placed at 1.5, 2.5, 3.5, 4.5, 5.5, 6.5 and 7.5 feet on center above the ground. These positions would correspond to the center of each panel on the SARE and modified Cornell patternators. The same setup was repeated for the semi-gloss and gloss OfficeMax professional grade photo paper. Water sensitive paper (3” x 2”) was placed on the last patternator in the same arrangement with the 3” side being vertical. All papers were attached to the 2×4 with push pins. One at the top and one at the bottom. A total four replicates were run. The second test involved using red food coloring from Shank’s. The same size and type of paper used in the first test were repeated. Four replicates were completed.

The third test again used red food coloring but the size and number of the paper cards was changed. The types of paper utilized in this test were the same as in the first and second. One patternator used fourteen 3” x 4” cards of OfficeMax professional grade matte photo paper. The cards were arranged with the 4” side being vertical. Cards were placed at 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0 and 7.5 feet on center above the ground. This doubled the number of positions on the patternators. The same setup was repeated for the semi-gloss and gloss OfficeMax professional grade photo papers. Water sensitive paper was placed on the last patternator in the same arrangement with the 3” side being vertical. All papers were attached to the 2×4 with push pins. One at the top and one at the bottom. A total four replicates were run. The fourth test used red food coloring but two new papers were introduced. Fourteen 3” x 4” cards with the same placement as the third test were used on each patternator. Gloss and matte OfficeMax professional grade photo paper were repeated. The new papers introduced were Hewlett-Packard Everyday gloss and Premium matte. All papers were attached to the 2×4 with push pins. One at the top and one at the bottom. Four replicates were completed.

An image analysis software program written in C was developed to interpret scanned photographic printer or water sensitive papers. Part of the image analysis software is a scanning program that allows multiple cards to be scanned simultaneously with Linux. If Mac or Windows are used the scanner’s program must be used for scanning the cards. The image analysis program for interpreting the cards has cross platform capabilities with Windows, Mac and OSX and is open source. The image analysis program measures percent coverage of the spray on each card, droplet density in droplets/cm² and droplet size in microns (μm). The droplet size is measured at the volume median diameter (VMD or Dv0.5) or the size at which 50% of the volume is in larger droplets and 50% of the volume is in smaller droplets. Results were interpreted with both the image analysis program developed in this project (NESareScan) and the USDA program DepositScan, which was developed exclusively for water sensitive paper. Statistical analysis of the results was done using the online site www.vassarstats.net. Depending on the number of variables being tested either a two-tailed t test for independent samples or a one-way analysis of variance (ANOVA) with Tukey’s hsd test were run.

Research results and discussion:
Results and Discussion

The total output of each nozzle on the left side of the sprayer was measured to insure no significant difference existed between the three nozzles. A plastic one gallon jug was placed over each nozzle and securely fastened. With the PTO running at 450 RPM, the spray was collected for one minute at 70 PSI. Knowing the total output of the sprayer will allow the determination of the percentage of total spray captured by each patternator developed in the 2010 project. Four replicates were run and the amount of water collected was measured in milliliters. The mean total output of the four replicates was 1969 milliliters.

Table 1. Total output of three Berthoud Saphirex 10 discs for one minute. See attached table.

Retesting 2010 Patternators In order to compare the patternators developed in the 2010 NESARE project with the paper patternators in the 2012 project, the SARE and modified Cornell patternators were retested. The mid-line of the sprayer was positioned 4.5 feet from the patternator surface. The height of the sprayer remained constant through all testing. For each test the tractor was positioned with the sprayer nozzles in line with the leading edge of the patternator. This position maximized the collection of sprayer effluent. Tractor PTO was set at 450 RPM for all tests with an ES 332 laser tachometer. Sprayer nozzles were opened for one minute during each test. All patternators received a one minute trial run before any measurements were made. This trial run was made to insure all surfaces had been exposed to the spray and any water adhesion due to surface tension had occurred. With no trial run, the initial test would have slightly lower amounts of water collected in the containers. Four replicates were run for each test. Statistical analysis was performed between the same panels on the two patternators. Panel #1 is positioned to collect spray from one to two feet off the ground. Panel #2 is positioned to collect spray from two to three feet off the ground and so forth. The top panel is #7 which collects spray from seven to eight feet off the ground. A two-tailed t test for independent samples was run for comparing the two patternators.

Table 2. Panel #7 See attached table.

Table 3. Panel #6 See attached table.

Table 4. Panel #5 See attached table.

Table 5. Panel #4 See attached table.

Table 6. Panel #3 See attached table.

Table 7. Panel #2 See attached table.

Table 8. Panel #1 See attached table. As in 2010, the SARE patternator captured significantly more spray material than the modified Cornell patternator on all panels except the bottom (#1) and the top (#7) panels. The 2nd through 6th panels were significantly different at the 1% level. Total Spray Recovery The mean of the total amount of spray captured by the SARE and modified Cornell patternator was calculated. The mean of the four replicates for each patternator was compared to the mean of the replicates for the total output of the sprayer to give the percentage recovery.

Table 9. Total spray recovery See attached table. The percentage of the total spray captured by the two patternators reiterates the statistical significance found when comparing the individual panels. The SARE patternator captured more than twice as much total spray as compared to the modified Cornell patternator. Similar results were obtained in 2010. Droplet Density Droplet density is measured in droplets per square centimeter. The USDA DepositScan program was developed to interpret spray droplets from boom sprayers on water sensitive paper. When using a boom sprayer, spray droplets fall downward from gravity and the pressure of the sprayer system. The amount of spray coverage on a surface with a boom sprayer is usually much less than that encountered when using an air blast sprayer. The integrity and size of the spray droplets is much more consistent with a boom sprayer. With an air blast sprayer, a high velocity stream of air initially carries the spray droplets horizontal to the ground. Droplets can be sheared apart and combined by the stream of air. The high velocity air also moves droplets across the card surface initially before they are absorbed on the card creating many oval and elongated shapes. All of these variables create a situation where it is difficult to determine droplet density with both the NESareScan and DepositScan programs using an air blast sprayer. The DepositScan program found significant differences between the various papers. In the first test using the blue turf spray pattern indicator, the water sensitive paper usually had a significantly higher droplet density than the other papers. For the cards at 1.5 and 7.5 feet there was no significant difference, but at the other five heights there were differences.

Table 10. Blue Turf Spray Indicator with Various Papers at 2.5 feet above ground using DepositScan 1st test See attached table. At 3.5 and 4.5 feet, the water sensitive paper had significantly higher densities at the 1% level. While at 5.5 and 6.5 feet, the water sensitive paper had significant higher densities than gloss and semi-gloss papers at the 5% level. Similar results were found using the red food coloring in the second test. In the third test using red food coloring, the matte paper was found to have a significantly higher droplet density than the other papers on the cards at 2.5 feet through 7.5 feet. The level of significance was usually 1%.

Table 11. Red food coloring with Various Papers at 5.5 feet above ground using DepositScan 3rd test See attached table. With the DepositScan program the highest droplet densities were recorded with the cards at 7.5 feet above the ground in all tests but one. The highest percent coverage was recorded at 3.5 feet in all the tests. Droplet density varied substantially between cards with nearly the same percent coverage. As an example, in the third test using red food coloring and Office Max professional grade gloss paper, the average of the four replicates for the cards at 7.5 feet had 22.5% coverage and a droplet density of 126.25 droplets per cm². The cards at 2.5 feet had an average of 25.5% coverage and a droplet density of 65.75 droplets per cm². This relationship was seen in all the tests and could be explained by the varying size of the droplets. In this example the Dv0.5 for the card at 7.5 feet is 577 µm and the Dv0.5 for the card at 2.5 feet is 785 µm. Larger droplets would require fewer droplets to have the same percent coverage.

While the DepositScan program appears to give good data when determining droplets/cm² for all the cards, the absurdity of the data becomes apparent when it is combined with the data for the volume median diameter. Using the previous example, the card at 3.0 feet has a percent coverage of 43.6%, 56.3 droplets/cm² and a Dv0.5 of 3768 µm. That would be a droplet of nearly 4 millimeters in diameter! The card at 3.5 feet has a percent coverage of 51%, 45 droplets/cm² and a Dv0.5 of 7347 µm or a droplet of 7.3 millimeters in diameter! By observing the spray plume with the naked eye we know no droplets are that large. This same pattern is seen in all the tests. With the NESareScan program the highest droplet densities were usually recorded with the cards at 7.5 feet, the same as the DepositScan program. In the first and second tests a different result occurred with both the gloss and matte papers – the highest droplet densities were recorded at 2.5 feet above the ground. The highest percent coverage was recorded at 3.5 feet in all the tests with the NESareScan program, the same result as the DepositScan program. The droplet density varied substantially between cards with nearly the same percent coverage when using the NESareScan program.

Using the same example as before, in the third test using red food coloring and Office Max professional grade gloss paper, the average of the four replicates for the cards at 7.5 feet had 19.1% coverage and a droplet density of 31.7 droplets per cm². The cards at 2.5 feet had an average of 22.9% coverage and a droplet density of 17.9 droplets per cm². This relationship was seen in all the tests and could be explained by the varying size of the droplets. In this example the Dv0.5 for the card at 7.5 feet is 501 µm and the Dv0.5 for the card at 2.5 feet is 705 µm. Larger droplets would require fewer droplets to have the same percent coverage. The NESareScan program differed significantly from the DepositScan program in calculating droplets/cm². At high coverage rates the DepositScan program would give what seemed a reasonable number of droplets/cm², while the NESareScan would give a result of zero or a very low number because of the inability to distinguish droplets due to overlap. At a high percentage coverage the NESareScan also reported extremely large droplets. Using the same example as previously-the 3rd test using red food coloring and Office Max professional grade gloss paper, the card at 3.0 feet has a percent coverage of 49.5%, 6.4 droplets/cm² and a Dv0.5 of 9319 µm. That would be a droplet of over 9 millimeters in diameter! The card at 3.5 feet has a percent coverage of 64.4%, 0 droplets/cm² and a Dv0.5 of 20932 µm or a droplet of 21 millimeters in diameter!

Again, by observing the spray plume with the naked eye we can detemine no droplets are that large. This same pattern is seen in all the tests. To test for significant difference in determining droplet density between the NESareScan program and the DepositScan program two-tailed t-tests for independent samples were run using VassarStats. From the first test using the blue turf spray pattern indicator, six cards of water sensitive paper showed significant differences with the DepositScan program yielding higher droplet densities. The cards at 5.5 and 6.5 feet above the ground had a significant difference of 5%, while the cards at 2.5, 3.5, 4.5 and 7.7 were significant at the 1% level. In the second test using red food coloring and matte paper, all seven cards were significantly different with the DepositScan program yielding higher droplet densities. The cards at 1.5 and 6.5 feet above the ground were significant at the 5% level and the other cards had a significant difference of 1%. In the third test using red food coloring and gloss paper, the first two cards at 1.0 and 1.5 feet above the ground were not significant, while the card at 7.5 feet was significant at the 5% level. All the other eleven cards were significantly different at the 1% level. Again the DepositScan program gave higher droplet densities than the NESareScan program. Examination of the other means reveal that all the results for droplet density, when comparing the two programs, are significantly different.

Neither the NESareScan program or the DepositScan program should be utilized when trying to determine droplet density with an air blast sprayer. The volume of spray and the dynamics of an airblast sprayer create a spray pattern that is nearly impossible to read in regards to the droplet density. Droplet Size The NESareScan computer program for interpreting spray cards determines the volume median diameter. This can be written as VMD or Dv0.5. The volume median diameter is the point where 50% of the volume is in larger droplets and 50% of the volume is in smaller droplets. Droplet size is measured in microns or micrometers (µm). Once the percent coverage reaches 20%, the droplet size becomes very difficult to measure. The measurement is the most accurate at a very low droplet density or percentage coverage. As the percent coverage increases the droplet size also increases with both the NESareScan and DepositScan programs. Statistically some significant differences were found in the droplet size. The blue turf spray pattern indicator had significant differences between the water sensitive paper and the other papers used during the first test when analyzed using both NESareScan and DepositScan. Tukey’s hsd test was run comparing the various papers with the blue dye. Only the samples taken close to ground were used for statistical analysis. For the first test only the cards at 1.5 feet above the ground were analyzed. These were the cards that consistently had less than 20% coverage and allowed a more accurate determination of droplet size.

Table 12. Blue Turf Spray Indicator with Various Papers at 1.5 feet above ground using NESareScan See attached table.

Table 13. Blue Turf Spray Indicator with Various Papers at 1.5 feet above ground using DepositScan See attached table. No significant differences were found with the red food coloring and the various papers in the second, third or fourth tests at the same height with both NESareScan and DepositScan. In the second test only the cards at 1.5 feet were analyzed and for the third and fourth tests the cards at 1.0, 1.5 and 2.0 feet were analyzed. The droplet size does increase as the percentage coverage increases for both dyes and all papers. The same is true with both NESareScan and DepositScan.

Table 14. Droplet Size (VMD in µm ) and percent coverage from third test (red dye) at three heights,mean of four replicates, using NESareScan See attached table. This is a typical result that occurred in all the tests. The lowest percentage coverage cards should be the only ones used for determining droplet size. The blue turf spray indicator and red food coloring were analyzed for any significant difference between the two dyes in determining droplet size. The dyes were compared in the first and second tests with same paper at the same height of 1.5 feet above the ground. The only significant difference found was with the matte paper using NESareScan. No significant difference was found when using droplet size from the DepositScan data. A two-tailed t test for independent samples was utilized.

Table 15. Droplet Size (VMD in µm) of blue and red dye on matte paper at 1.5 feet, mean of four replicates, using NESareScan See attached table. The red food coloring had smaller droplet sizes than the blue turf indicator in the two tests but only the matte paper was significantly different when using the NESareScan data. The results from NESareScan and DepositScan were compared to determine if there were any significant differences between the two scanning programs. Two-tailed t tests were used to compare exactly the same test results from the two programs. No significant difference was found with the blue turf spray indicator and the four different paper during the first test at a height of 1.5 feet. Also no significant differences were found in the third and fourth tests with red food coloring and the various papers at heights of 1.0, 1.5 and 2.0 feet above the ground. One significant difference was found during the second test using red food coloring and matte paper at 1.5 feet. No other significant differences were found with the other papers during the second test.

Table 16. Droplet Size (VMD in µm) with red dye on matte paper at 1.5 feet, mean of four replicates, using NESareScan and DepositScan See attached table. Percent Coverage Of the three parameters tested by the computer programs, percent coverage is probably the most valuable for most farmers. It is also the one measurement that is accurate whether using an airblast or boom sprayer. The percent coverage can be used to adjust the nozzle positions on an airblast sprayer in the same manner as the patternators developed in the 2010 NESare project. Blue Dye – Different Papers (1st Test) Some significant differences were found depending on the paper, dye or program utilized. When using the blue spray pattern indicator, significant differences were found with the NESareScan program at 2.5 to 6.5 feet above the ground. The percent coverage on the gloss, semi-gloss and matte papers was significantly higher than the water sensitive paper, usually at the 1% level of significance. A typical example would be the cards at 3.5 feet above the ground.

Table 17. Blue Turf Spray Indicator with Various Papers at 3.5 feet above ground using NESareScan See attached table. No statistical significance was found at 1.5 and 7.5 feet above the ground. With the DepositScan program and blue dye, significant differences between the papers was found only at 2.5 and 3.5 feet above the ground. At each of these two heights only one significant difference at the 5% level was found between the gloss and matte paper.

Table 18. Blue Turf Spray Indicator with Various Papers at 3.5 feet above ground using DepositScan See attached table. Red Dye – Different Papers (2nd 3rd 4th Tests) Very few significant differences were found between the various papers when using red food coloring and the NESareScan program. With the second test, a significant difference was found only at 5.5 feet above the ground. The semi-gloss paper had significantly higher coverage than the water sensitive paper at the 5% level. All others papers at the various heights were not significant.

Table 19. Red food coloring with Various Papers at 5.5 feet above ground using NESareScan – 2nd test See attached table. Using the DepositScan program on the results from the second test, a significant difference was found at 3.5 feet above the ground between the gloss and water sensitive paper.

Table 20. Red food coloring with Various Papers at 3.5 feet above ground using DepositScan – 2nd test See attached table. The third test yielded no significant difference for any paper or height with the NESareScan program. Significant differences were found using the DepositScan program. At 3.5, 4.0, 4.5, 5.0, 5.5, 7.0 and 7.5 feet above the ground the percent coverage was significantly higher for the water sensitive paper versus the other papers. A 1% level of significance was found at 4.0, 4.5 and 5.0 feet between the water sensitive paper and the three other papers. At 3.5 feet, the water sensitive paper had a greater coverage than the matte paper at a 5% level of significance while the gloss and semi-gloss papers were lower at a 1% level of significance. At 5.5 feet only the matte paper was significantly lower at 5% level of significance, while at 7.0 feet the gloss paper was significantly lower at the 5% level. At 7.5 feet the gloss and semi-gloss papers were significantly lower at the 5% level and the matte paper was at the 1% level.

Table 21. Red food coloring with Various Papers at 4.5 feet above ground using DepositScan – 3rd test See attached table. The fourth test results had a few significant differences with the NESareScan program. The percent coverage on the gloss paper was significantly higher than the H-P matte paper at 5.0 and 5.5 feet above the ground. The difference was at a 5% level of significance. At 4.5 feet above the ground, the H-P gloss was significantly higher than the H-P matte paper at a 5% level of significance.

Table 22. Red food coloring with Various Papers at 5.0 feet above ground using NESareScan – 4th test See attached table. Like the NESareScan program, a few significant differences were found with DepositScan program with the fourth test results. The H-P gloss paper had a significantly higher percent coverage than the H-P matte paper at 4.5 feet. The level of significance was 5%. The same result occurred at 7.5 feet. At 5.0 feet above the ground, the Office Max and H-P gloss papers were significantly higher than the H-P matte paper.

Table 23. Red food coloring with Various Papers at 5.0 feet above ground using DepositScan – 4th test See attached table. Blue Dye versus Red Dye (1st & 2nd tests) The percent coverage for each of the two dyes can be compared between the first and second tests when the only parameter that changed was the dye. The results were compared utilizing the two-tailed t-test for independent samples. Using the NESareScan program the blue spray pattern indicator had significantly greater percent coverage than the red food coloring with the gloss, semi-gloss and matte papers at nearly all the heights. The only heights that did not have a significant difference were the cards at 1.5 feet above the ground for all three and the cards at 7.5 feet for the semi-gloss and matte papers. No significant differences were found for the water sensitive paper. Most of the differences were at the 1% level of significance. A difference at the 5% level of significance tended to found at the lower or higher cards. The results for the matte paper are typical.

Table 24. Blue Spray Indicator compared to Red Food Coloring using matte paper and NESareScan See attached table. The percent coverage for the blue dye versus the red dye was compared using DepositScan. The results were compared utilizing the two-tailed t-test for independent samples. The blue spray pattern indicator had significantly greater percent coverage than the red food coloring with the gloss, semi-gloss and matte papers at most heights. The only result where the red dye had significantly greater coverage than the blue dye occurred with the matte paper at 1.5 feet above the ground. The only heights that did not have a significant difference were the cards at 7.5 and 2.5 feet above the ground for all three and the cards at 1.5 feet for the gloss and semi-gloss papers. No significant differences were found for the water sensitive paper. Many of the differences were at the 1% level of significance. The results for the matte paper are typical.

Table 25. Blue Spray Indicator compared to Red Food Coloring using matte paper and DepositScan See attached table. Date of Testing Was there any significant difference in the percent coverage results based on the day of testing? In the third and fourth tests all parameters were the same for two of the papers – Office Max professional grade gloss and matte papers. The same paper at the same height was compared between the two days using the NESareScan results and a two tailed t-test for independent samples. No significant difference was found with either paper at all the heights. NESareScan versus DepositScan The results from each test can be compared for any significant difference in the percent coverage between the NESareScan program and the DepositScan program. Each paper was compared at every height with a two tailed t-test for independent samples. In the first test, using the blue spray pattern indicator, some significant differences were found for each paper at the highest percent coverages. Using the gloss paper, the NESareScan program gave significantly greater coverages at the 1% level on the cards at 3.5 and 4.5 feet above the ground. Similar results were found with the semi-gloss paper. With the NESareScan program, significantly higher results were found at the 1% level for cards placed at 3.5, 4.5, 5.5 and 6.5 feet. For the matte paper the only significant difference was at 3.5 feet at a 5% level with the NESareScan having a greater result. When using the water sensitive paper only the DepositScan program had a significant difference. At 4.5 feet above the ground, the DepositScan program gave a result that was significantly greater at the 1% level.

Table 26. NESareScan versus DepositScan Percent Coverage with Blue SPI 1st test See attached table. Some significant differences between the NESareScan and DepositScan programs were also found in the second test using red food coloring. With the gloss paper, the DepositScan program gave a higher percent coverage at the 1% level on the card placed at 2.5 feet. On the card placed at 3.5 feet, the NESareScan program gave a higher result at the 1% level of significance. One significant difference was found when using the semi-gloss paper. At 3.5 feet the NESareScan program gave a result that was significantly greater at the 5% level. A number of significant differences were found when using the matte paper. The NESareScan program gave higher results at a 1% level of significance for the cards at 3.5 and 4.5 feet. The DepositScan program gave a higher result at the 1% level of significance for the card at 2.5 feet and a higher result at the 5% level of significance for the card at 1.5 feet. The DepositScan program also gave significantly different results with the water sensitive paper. At 6.5 feet, it gave a significantly higher result at the 1% level of significance and at 7.5 feet it gave a significantly higher result at the 5% level of significance.

Table 27. NESareScan versus DepositScan Percent Coverage with Red Food Coloring 2nd test See attached table. A few significant differences were found in the third test between the NESareScan and DepositScan programs. The third test repeated the use of red food coloring but reduced the size of the cards and doubled the number of cards to fourteen. The same photographic papers were used as in the second test. With the gloss paper two cards were significantly different. The NESareScan program gave a higher result at the 1% level of significance for the card at 3.5 feet and a higher result at the 5% level of significance for the card at 4.0 feet. The NESareScan program also gave results that were significantly higher for the semi-gloss paper. The cards at 3.5, 4.0 and 5.0 had a higher percentage coverage at the 5% level of significance. When using the matte paper the DepositScan program had a result that was significantly different. The card at 7.5 feet had a higher percentage coverage at the 5% level of significance. No significant differences were found with the water sensitive paper.

Table 28. NESareScan versus DepositScan Percent Coverage with Red Food Coloring 3rd test See attached table. In the fourth test using red food coloring and two different papers a few significant differences were found. In a repeat with the gloss paper used in the third test, significant differences were found on the cards at 3.5 and 5.0 feet with the NESareScan program at a 5% level of significance. With the Hewlett-Packard matte paper a significant difference was found with the card at 3.5 feet. The percentage coverage was significant greater at a 5% level of significance with NESareScan program. No significant differences were found with the matte or Hewlett-Packard gloss papers.

Table 29. NESareScan versus DepositScan Percent Coverage with Red Food Coloring 4th test See attached table. 6. Economics No economic findings can be reported with this project. The project was not designed to test for any variation, positive or negative, in vineyard performance due to the use of patternators. Eventually the use of a patternator would improve sprayer performance and reduce the incidence of disease and insect problems. With a reduction in losses due to disease and pests, farm income would increase. The paper patternators used in this project are a more economical alternative to the patternators developed in the 2010 NESare project. The construction of one paper patternator had a total cost of $44.45. Only a few supplies are needed.

Table 30. Cost of one paper patternator used in 2012 NESare project See attached table.

Participation Summary

Education & Outreach Activities and Participation Summary

Participation Summary

Education/outreach description:

The paper patternators tested in this project along with the SARE patternator from the 2010 project were displayed and demonstrated during a one hour field day presentation held at our farm on August 16, 2012. A handout on the construction and use of a low cost paper patternator was available. Graphs showing the percent coverage with two different dyes and different photographic papers was presented. These graphs were compared to a graph showing the amount of spray captured by the SARE patternator developed in the 2010 project. The meeting was listed on the Penn State grape extension email listing for upcoming viticulture events. The Pennsylvania Department of Agriculture approved the meeting for 2 core pesticide credits and listed the meeting on the Bureau of Plant Industry’s pesticide recertification course locater on the PDA website. The meeting was also approved for 2 core pesticide credits by the Maryland Department of Agriculture and listed on their recertification course website. University of Maryland’s extension specialist in viticulture and small fruit also sent out an email through his mailing list detailing the meeting. Although the meeting was well publicized and generated 2 core credits, it was attended by only three grape growers. A half hour power point presentation (see Figure 1 uploaded below) on the 2012 NESARE paper patternator project was presented at the Penn State Grape IPM Workshop on March 19, 2013 in Lancaster, PA. The meeting was sponsored by the Penn State Cooperative Extension and had 47 attendees in Lancaster. The meeting was also simultaneously transmitted by video to three other locations, Susquehanna, Erie and Washington Counties, in Pennsylvania. One core pesticide credit was available to attendees. A website has been created to present the results of this project and the previous project in 2010. The URL is www.patternator.com. The state viticulture extension agents in Pennsylvania, Maryland and New Jersey have been contacted about the website. The power point presentation from the Penn State Grape IPM Workshop held on March 19, 2013 is available on the Pennsylvania Wine Grape Network at www.pawinegrape.com/index.php?page=workshop-meeting-summaries.

Project Outcomes

Assessment of Project Approach and Areas of Further Study:

Future Recommendations

Adoption and Assessment

Every design of patternator has its limitations. It can be difficult to get accurate measurements. The measurements can vary for different reasons depending on the patternator design. In 2010 the designs resulted in a varying loss of spray material depending on the patternator. In this project the spray was collected for a very short period of time. The patternators used in the 2010 project collected spray for one minute, which helped eliminate any variability due to sprayer output. In 2012 the amount of spray collected depends on the speed of the tractor and the width of spray plume. The width of the spray plume depends on the nozzle, nozzle setting and pressure. Our tractor speed in this project and in 2010 was 2.68 miles per hour and the width of the spray plume was approximately 30 inches wide at 4.5 feet from the center line of the sprayer. With these parameters a card at 3.5 feet above the ground is exposed to the spray for only 0.64 seconds. At 3 miles per hour the time would be 0.57 seconds and at 4 mph the time would be 0.43 seconds. The extremely short sample time can increase the variability.

In order to make the card readings more accurate multiple samples should be recorded. With the card patternator there is also a loss of accuracy due to the overlap of droplets. As the amount of spray increases more and more spray hits an area that was already covered. After about 20% coverage the cards become less accurate because of spray overlap. This inaccuracy increases as coverage increases. The size of a droplet can easily double if only a small amount of the droplet overlaps another droplet. Cards are very accurate in determining the actual percent coverage, which correlates to the coverage on plants. Although the cards are accurate in determining percent coverage, a mature grape vine or any plant is a much more complex system than a flat card. Some areas of the plant receive an amount of spray analogous to that found on a card while other areas of the plant receive almost no spray because of overlapping leaves and fruit. One outstanding benefit of a photographic paper card patternator is that it can be used with any type of sprayer. It would work equally well with backpack sprayers, horizontal boom sprayers or airblast sprayers.

Assessment In 2012 the amount of spray material captured by the modified Cornell patternator increased over the results from 2010, while the amount of spray material captured by the SARE patternator decreased. The modified Cornell patternator captured 24% of the spray material as opposed to 13 to 18% in 2010 and the SARE patternator captured 53.1% in 2012 as compared to 62 to 63% in 2010. The SARE patternator still captured more than twice as much spray (2.2 times more) as the Cornell design. The SARE patternator captured significantly more spray material than the Cornell design on all the panels except the top and bottom. The second through sixth panels panels were significantly different at the 1% level.

Due to the high volume of spray material and the dynamics of the spray plume in an airblast sprayer, the results for droplet density should not be utilized for either the NESareScan or DepositScan programs. Overlapping droplets and droplet shapes modified by the high velocity air make it difficult to determine the droplet density. Results from the NESareScan and DepositScan were found to be significantly different. At high percent coverages the NESareScan would give a result of zero because of droplet overlap while the DepositScan would give a number for the droplet density. In determining droplet size, the NESareScan program calculates the volume median diameter which is written as VMD or Dv0.5. Once the percent coverage reaches 20%, the droplet size becomes very difficult to measure. The measurement is the most accurate at very low percent coverage. In calculating droplet size only cards with less than 5% coverage should be used. The droplet size increases as the percentage coverage increases with both the NESareScan and DepositScan programs. The blue spray pattern indicator gave statistically smaller droplet sizes on the water sensitive paper in both the NESareScan and DepositScan programs.

No statistical differences were found with the red food coloring in either computer program. The NESareScan program gave smaller droplet sizes than DepositScan but only once was the result statistically significant. Percent coverage proved to be the most accurate of the three parameters measured by the computer programs. Differences were found based on the paper, dye or program utilized. With the blue spray pattern indicator, the percent coverage means were higher and statistically significant with the three photographic papers as compared to the the water sensitive paper at all heights between 2.5 and 6.5 feet when using the NESareScan program.

Almost no statistical significance was found with the same results with the blue spray pattern indicator and the DepositScan program. When using the red food coloring very few significant differences were found between the papers with the NESareScan program. In the second test only one significant difference was found, in the third test no differences were found and in the fourth test only three significant differences were found out of 56 possible combinations. More significant differences were found with the DepositScan program and the red food coloring.In the second test one significant difference was found, but not the same one found with the NESareScan program.

In the third test, the water sensitive paper had significantly higher coverage than all three photographic papers on five of the fourteen card locations. Additional significant differences were found with the water sensitive papers on a few other cards. In the fourth test, four significant differences were found out of the 56 possible combinations and two significant differences matched those found with the NESareScan program.

When comparing the blue spray pattern indicator to the red food coloring, the blue dye had a significantly greater percent coverage than the red food coloring with the gloss, semi-gloss and matte papers at nearly all the heights with the NESareScan program. No significant differences were found for the water sensitive paper. With the DepositScan program, the blue dye had a significantly greater percent coverage with the gloss, semi-gloss and matte papers at most heights. Again no significant differences were found for the water sensitive paper.

The results from each test can be compared for any significant difference in the percent coverage between the NESareScan and DepositScan programs using a two-tailed t-test. The only trend that appeared was the NESareScan program tended to give higher results for the gloss and semi-gloss papers at a high percent coverage. Out of 168 statistical comparisons run between the NESareScan and DepositScan programs for percent coverage, 26 showed a statistical differences or 15.5% of the total. Of the 26 statistically significant differences, 19 times the NESareScan had a higher result and 7 times the DepositScan had a higher result.

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.