Re: Apple-Crop: Pesticide Rates and Tree Row Volume
Hi all, I'm sitting in an airport about to leave for Quebec to talk about Crop-Adapted Spraying to a group of apple researchers. Now that I've figured out how to post properly, I wanted to speak to Jonathan's point that regulatory agencies should make clear labelled changes to reflect the reality of orchard applications. In Canada, I've spoken with Heath Canada's Pest Management Regulatory Agency (who control label language and product registration) and Croplife Canada (the registrants that create agrichemicals) about this very point. A few registrants from the states claimed that they have attempted to put concentrations on their label, but the regulatory agencies insisted on per-acre units of measurement. When I asked the PMRA why that was, they said they had so much infrastructure oriented towards those units that it was a huge undertaking to consider changing them. All of their models for toxicity, rick, contamination, etc. are based on ground-area units. Both groups acknowledge the disconnect between units and grower practices, but don't seem to know what to do about it. Researchers have made a few suggestions to close the gap, and Jonathan touched on a few. One is establishing a standardized tree for determining label rates. Everyone would know it's volume, density, stage of growth and the environmental conditions for each and every product. Two is to use airblast sprayers with standardized set-up; no more spray guns for testing. Three is to publish coverage and efficacy variability on the label. For example, it might state discrete droplets per square centimetre in key locations on the tree, with variability. And/or it might note how many trees achieved what level of protection out of the total sprayed. All three approaches equal transparency. They make test methods that establish label rates as close to standard grower methods as realistically possible and they give the grower the data to adjust their methods based on the standardized conditions - a basis for comparison. This would still leave growers making adjustments in an ad hoc manner, but they would be based on more solid ground. None of this, however, changes the current fact that if a growers applies a rate and/or volume that departs from label-recommended values, they assume responsibility for any consequences. Sadly, I'm not sure how that would change. My hope is to either encourage standardized testing, encourage system-wide change to accept new label units, or give growers a simple and flexible tool to interpret labels (Crop-adapted spraying). Looking forward to comments. Jason Deveau Application Technology Specialist OMAFRA -- Sent using BlackBerry - Original Message - From: apple-crop@virtualorchard.net apple-crop@virtualorchard.net To: apple-crop@virtualorchard.net apple-crop@virtualorchard.net Sent: Mon Jan 25 21:14:37 2010 Subject: Re: Apple-Crop: Pesticide Rates and Tree Row Volume Hello All, I have found the discussion that has arisen from my initial questions fascinating and the answers nowhere near as clear-cut as I had imagined. My original post included a plea to the pesticide manufacturers, EPA and what is left of our unfortunately underfunded extension experts to come up with a product labeling requirement that takes into consideration the complexities of applying pesticides to fruit trees. I would assume that CLARITY would be of utmost interest to the EPA, whether or not they actually care if the product works. ( Maybe important enough that they would back it up with dollars for research?) I don't buy the Don't confuse the poor farmer by making them do algebra. argument. I also have trouble accepting the argument that a small tree equals a big tree. There is a limit to how dense the fruit and foliage can be before fruit quality suffers from light deprivation. Small trees put tree and fruit closer to the sprayer and have a smaller row volume. Our big old trees might not have grown as good quality fruit in the center of the tree, but there was still a need to protect it from insects and disease and thus a need to fill that volume of space with a cloud of spray mist that deposited an effective dose of pesticide. The variation on the TRV calculation that Jason Deveau discusses in his post might be based on better assumptions than our current approach, but it still contains the caveat that reducing the rate is at the grower's risk. We need a methodology that everyone can agree on so that if you do it right, the manufacturer will stand behind the product instead of hiding behind the lawyerly language written in tiny print on the label. I understand, as Dave Rosenberger points out, that from the manufacturer's perspective they might be recommending the least amount of product possible to leave more room in there risk cup for other crops, but if the rate is so close to the line so there is no margin for error, this needs
Re: Apple-Crop: Pesticide Rates and Tree Row Volume
Hello All, I have found the discussion that has arisen from my initial questions fascinating and the answers nowhere near as clear-cut as I had imagined. My original post included a plea to the pesticide manufacturers, EPA and what is left of our unfortunately underfunded extension experts to come up with a product labeling requirement that takes into consideration the complexities of applying pesticides to fruit trees. I would assume that CLARITY would be of utmost interest to the EPA, whether or not they actually care if the product works. ( Maybe important enough that they would back it up with dollars for research?) I don't buy the Don't confuse the poor farmer by making them do algebra. argument. I also have trouble accepting the argument that a small tree equals a big tree. There is a limit to how dense the fruit and foliage can be before fruit quality suffers from light deprivation. Small trees put tree and fruit closer to the sprayer and have a smaller row volume. Our big old trees might not have grown as good quality fruit in the center of the tree, but there was still a need to protect it from insects and disease and thus a need to fill that volume of space with a cloud of spray mist that deposited an effective dose of pesticide. The variation on the TRV calculation that Jason Deveau discusses in his post might be based on better assumptions than our current approach, but it still contains the caveat that reducing the rate is at the grower's risk. We need a methodology that everyone can agree on so that if you do it right, the manufacturer will stand behind the product instead of hiding behind the lawyerly language written in tiny print on the label. I understand, as Dave Rosenberger points out, that from the manufacturer's perspective they might be recommending the least amount of product possible to leave more room in there risk cup for other crops, but if the rate is so close to the line so there is no margin for error, this needs to be communicated more effectively. Perhaps if the EPA was comparing how much Avaunt it really took to actually control Apple Maggot versus the actual rate of an O.P. that was being sprayed to accomplish complete control of the same pest ( I was one of those 1/4 - 1/8th rate growers that Kathleen Leahy referred to) they wouldn't feel quite the need to give the O.P.'s the bum's rush! As growers we have no way to know what assumptions have gone into the labeling of the pesticides we use. For example, if all the testing is already done on smaller trees and there really is no room to cut the rate further, this needs to somehow be made clear on the product label. I think Dave Kollas' frustration (one that I share) with labels that don't include a rate/100 gallons is based on a recognition that we need to have a common reference point.( not to mention a method for a small grower with a few trees and a backpack sprayer to figure out a dilute rate for his hand sprayer.) If the old assumptions are no longer valid, fine... lets develop some new ones, but it seems plain silly to plod forward with the kind of tower of babble labeling that we have now. Regards, Jonathan Bishop ??? B.W. Bishop Sons, Inc. Bishop's Orchards 1355 Boston Post RoadGrowers of Fine Fruit Guilford, CT 06437 Since 1871 Vistit us on the web at: www.bishopsorchards.com ?? -- The 'Apple-Crop' LISTSERV is sponsored by the Virtual Orchard http://www.virtualorchard.net and managed by Win Cowgill and Jon Clements webmas...@virtualorchard.net. Apple-Crop is not moderated. Therefore, the statements do not represent official opinions and the Virtual Orchard takes no responsibility for the content.
RE: Apple-Crop: Pesticide Rates and Tree Row Volume
Hi, Harold -- No, you should not deduct the drive-space of the untraveled row when spraying on an alternate row basis because that unused row middle is still a functional and essential part of the orchard (i.e., you drive that space on the next spray). Your trees occupy the space within the dripline plus half of the drive space on either side of the tree. The fact that you don't use the drive space on each trip does not negate the amount of space that your trees are utilizing. In research orchards, some of the wide space between trees serves no function except as a distance barrier between plots. Incidentally, I did not mean to imply in my comments that I favored alternate row spraying, even though I can understand why it is widely used in high-density plantings. In orchards where scab control is a concern (especially given the very high carry-over inoculum that is present in some northeastern NY orchards right now), I'm not certain that alternate row spraying will provide adequate fungicide coverage for sprays applied at bloom and petal fall, even in high-density orchards on narrow spacings. When the DMI fungicides (Rally = myclobutanil, Rubigan = fenarimol) were working well, missing a few leaves shadowed by the trunk on the non-sprayed row middles was not very important because the DMI fungicides would shut down those infections when they were hit with fungicide on the next spray. With widespread resistance to DMIs, we no longer can be certain of eradicating infections that get started due to incomplete coverage. I don't have a practical solution since most growers can't afford the time required to drive every row middle with trees on 10-14 foot row-middle spacings. So Dave I am wondering if your thinking has merit in commercial orchards. I spray alternate rows with 13 foot row spacings. And I do very much like the idea of driving half the miles. I calculate things on a per-acre basis because I don't feel comfortable at 30 or 40 gpa spraying alternate rows. I depend on drift to finish the coverage on my side of the second row over. Should I be calculating the acreage minus the unused driveway? (Eliminate the unused space here so to speak) Rather than spraying a 26 ft row I am in fact spraying one 20 ft wide (subtracting a 6 ft alley down the middle I am not driving). This would reduce my acreage to 77% of what it was. I would still use the full amount of water (I still want the drift) but calculate rates at 23% less. Forget the question mark a couple of sentences back. It's not fair to ask you to condone rate cutting. Is the logic there? Harold Schooley Schooley Orchards Limited Simcoe, Ontario, Canada -Original Message- From: apple-crop@virtualorchard.net [mailto:apple-c...@virtualorchard.net] On Behalf Of Dave Rosenberger Sent: Tuesday, January 19, 2010 9:54 PM To: apple-crop@virtualorchard.net Subject: Re: Apple-Crop: Pesticide Rates and Tree Row Volume Hi, Rick -- Your method of testing insecticides and Duane Greene's comments about testing PGRs with airblast sprayers both make good sense. I know both of you are good scientists, so I don't mean to imply the following issue applies to your calculations of spray rates. However, it came to my attention recently that not all university researchers use the same method for calculating rates in airblast trials in research orchards even if one ignores TRV. The problems arise because many research orchards have wider spacings between tree rows than commercial orchards so as to minimize inter-plot interference from spray drift. However, one variable that is used to calibrate airblast sprayers is the spacing between rows. For example, growers might space apple trees on M.9 rootstock at 12 ft between rows whereas a test orchard might have 24 ft between rows. To spray one acre, the sprayer will need to travel twice as far in the commercial orchard as in the test orchard if one uses conventional calibration formulas. But if the applicator in the test orchard drives immediately adjacent to the test trees to apply fungicides (spraying from one side only into the test trees and then coming around to spray the opposite sides), then (s)he will be over-applying the product compared to a commercial orchard if the test-orchard sprayer is calibrated for a 24-ft row spacing. In my opinion, the correct calibration for research orchards is as follows: the sprayer should be parked in the drive row in the same position that will be used to spray the trees. One should measure from the tree trunk to the center of the sprayer fan and then double that number to determine the effective spacing between tree rows for the test orchard, and that number should be used for calibration rather than the real spacing in the orchard. Thus, in my experimental orchard with 24 ft between rows, I may allow my M.9 trees to get a bit wider than in a commercial orchard, so the limbs will extend outward 5 ft from
RE: Apple-Crop: Pesticide Rates and Tree Row Volume
Dave Alternate row spraying is attractive with today's equipment, labour and fuel costs. Years ago I sprayed rows 26 ft apart and it worked, so every other 13 ft seemed logical. Alternate row spraying has worked for me as long as I follow the rules I set out. Don't spray in the wind. Use enough water to drift to the next row (70-80 gpa is used). Drive slow enough to allow drift to the next row (3.5 mph or under). Don't do it on big trees especially when fully leafed out. I have a chart in the spray cab to switch from alternate to every row on the go if weather is not cooperating (switch gears, close nozzles) I am comfortable using EBDCs as a protectant with redistribution potential. I am comfortable with insecticides that don't necessarily require every leaf to be painted. I am not comfortable using it with systemic products, thinners, and miticides that require full coverage today. That brings up the fact again that registrations are now based on the lowest effective dose (at least here in Canada) and it gets us into trouble under adverse conditions. I still have the gut feel I am overspraying. Trees 8-10 ft tall 7 ft in diameter getting the same amount per acre as trees 16-18 ft tall and 20 ft wide. I have calculated the TRV of dwarf trees at 40% of the largest I once had. 2 rows would be 80%. Surely I can realize some efficiency cost here somewhere. Harold Schooley Schooley Orchards -Original Message- From: apple-crop@virtualorchard.net [mailto:apple-c...@virtualorchard.net] On Behalf Of Dave Rosenberger Sent: Thursday, January 21, 2010 9:22 AM To: apple-crop@virtualorchard.net Subject: RE: Apple-Crop: Pesticide Rates and Tree Row Volume Hi, Harold -- No, you should not deduct the drive-space of the untraveled row when spraying on an alternate row basis because that unused row middle is still a functional and essential part of the orchard (i.e., you drive that space on the next spray). Your trees occupy the space within the dripline plus half of the drive space on either side of the tree. The fact that you don't use the drive space on each trip does not negate the amount of space that your trees are utilizing. In research orchards, some of the wide space between trees serves no function except as a distance barrier between plots. Incidentally, I did not mean to imply in my comments that I favored alternate row spraying, even though I can understand why it is widely used in high-density plantings. In orchards where scab control is a concern (especially given the very high carry-over inoculum that is present in some northeastern NY orchards right now), I'm not certain that alternate row spraying will provide adequate fungicide coverage for sprays applied at bloom and petal fall, even in high-density orchards on narrow spacings. When the DMI fungicides (Rally = myclobutanil, Rubigan = fenarimol) were working well, missing a few leaves shadowed by the trunk on the non-sprayed row middles was not very important because the DMI fungicides would shut down those infections when they were hit with fungicide on the next spray. With widespread resistance to DMIs, we no longer can be certain of eradicating infections that get started due to incomplete coverage. I don't have a practical solution since most growers can't afford the time required to drive every row middle with trees on 10-14 foot row-middle spacings. So Dave I am wondering if your thinking has merit in commercial orchards. I spray alternate rows with 13 foot row spacings. And I do very much like the idea of driving half the miles. I calculate things on a per-acre basis because I don't feel comfortable at 30 or 40 gpa spraying alternate rows. I depend on drift to finish the coverage on my side of the second row over. Should I be calculating the acreage minus the unused driveway? (Eliminate the unused space here so to speak) Rather than spraying a 26 ft row I am in fact spraying one 20 ft wide (subtracting a 6 ft alley down the middle I am not driving). This would reduce my acreage to 77% of what it was. I would still use the full amount of water (I still want the drift) but calculate rates at 23% less. Forget the question mark a couple of sentences back. It's not fair to ask you to condone rate cutting. Is the logic there? Harold Schooley Schooley Orchards Limited Simcoe, Ontario, Canada -Original Message- From: apple-crop@virtualorchard.net [mailto:apple-c...@virtualorchard.net] On Behalf Of Dave Rosenberger Sent: Tuesday, January 19, 2010 9:54 PM To: apple-crop@virtualorchard.net Subject: Re: Apple-Crop: Pesticide Rates and Tree Row Volume Hi, Rick -- Your method of testing insecticides and Duane Greene's comments about testing PGRs with airblast sprayers both make good sense. I know both of you are good scientists, so I don't mean to imply the following issue applies to your calculations of spray rates. However, it came to my attention recently that not all
RE: Apple-Crop: Pesticide Rates and Tree Row Volume
Harold -- I don't doubt at all that you could use TRV or some other calculations to come up with rate reductions for smaller trees. The problem, as I see it, is that you if you wish to maximize your savings on pesticides you won't be able to use exactly the same rate reduction for every product. That is the reason that I am uncomfortable recommending TRV as a blanket approach for determining rates for smaller trees. The best growers that I have worked with over the past 30 years have done their own experimentation by gradually lowering rates of products like captan, mancozeb, and Guthion until they hit a break point (detected early via careful scouting), then bringing the rates back up slightly. They also adjust those minimum rates for weather, pest pressure, and tree growth stage. And they have confirmed from their own experimentation that one can cut rates of some products further than rates for other products. This kind of self-generated data is ideal because it is based on actual habits and practices of the growers involved. Unfortunately, it takes a lot of time and effort, and the process needs to be repeated every time one gets new products or a different model of sprayer. Dave Alternate row spraying is attractive with today's equipment, labour and fuel costs. Years ago I sprayed rows 26 ft apart and it worked, so every other 13 ft seemed logical. Alternate row spraying has worked for me as long as I follow the rules I set out. Don't spray in the wind. Use enough water to drift to the next row (70-80 gpa is used). Drive slow enough to allow drift to the next row (3.5 mph or under). Don't do it on big trees especially when fully leafed out. I have a chart in the spray cab to switch from alternate to every row on the go if weather is not cooperating (switch gears, close nozzles) I am comfortable using EBDCs as a protectant with redistribution potential. I am comfortable with insecticides that don't necessarily require every leaf to be painted. I am not comfortable using it with systemic products, thinners, and miticides that require full coverage today. That brings up the fact again that registrations are now based on the lowest effective dose (at least here in Canada) and it gets us into trouble under adverse conditions. I still have the gut feel I am overspraying. Trees 8-10 ft tall 7 ft in diameter getting the same amount per acre as trees 16-18 ft tall and 20 ft wide. I have calculated the TRV of dwarf trees at 40% of the largest I once had. 2 rows would be 80%. Surely I can realize some efficiency cost here somewhere. Harold Schooley Schooley Orchards -Original Message- From: apple-crop@virtualorchard.net [mailto:apple-c...@virtualorchard.net] On Behalf Of Dave Rosenberger Sent: Thursday, January 21, 2010 9:22 AM To: apple-crop@virtualorchard.net Subject: RE: Apple-Crop: Pesticide Rates and Tree Row Volume Hi, Harold -- No, you should not deduct the drive-space of the untraveled row when spraying on an alternate row basis because that unused row middle is still a functional and essential part of the orchard (i.e., you drive that space on the next spray). Your trees occupy the space within the dripline plus half of the drive space on either side of the tree. The fact that you don't use the drive space on each trip does not negate the amount of space that your trees are utilizing. In research orchards, some of the wide space between trees serves no function except as a distance barrier between plots. Incidentally, I did not mean to imply in my comments that I favored alternate row spraying, even though I can understand why it is widely used in high-density plantings. In orchards where scab control is a concern (especially given the very high carry-over inoculum that is present in some northeastern NY orchards right now), I'm not certain that alternate row spraying will provide adequate fungicide coverage for sprays applied at bloom and petal fall, even in high-density orchards on narrow spacings. When the DMI fungicides (Rally = myclobutanil, Rubigan = fenarimol) were working well, missing a few leaves shadowed by the trunk on the non-sprayed row middles was not very important because the DMI fungicides would shut down those infections when they were hit with fungicide on the next spray. With widespread resistance to DMIs, we no longer can be certain of eradicating infections that get started due to incomplete coverage. I don't have a practical solution since most growers can't afford the time required to drive every row middle with trees on 10-14 foot row-middle spacings. So Dave I am wondering if your thinking has merit in commercial orchards. I spray alternate rows with 13 foot row spacings. And I do very much like the idea of driving half the miles. I calculate things on a per-acre basis because I don't feel comfortable at 30 or 40 gpa spraying alternate rows. I depend on drift to finish the coverage on my side
Apple-Crop: Pesticide Rates and Tree Row Volume
Hello all. A little context before the main idea about how new insecticides (and other pesticides) are tested in tree fruit crops ... This thread started with a report that Avaunt performed poorly for apple maggot control when used in a spray program that relied on tree-row volume calculations. As a few others have pointed out, this seems to have been a banner year for apple maggot in many areas, so pest pressure likely helped to exaggerate anything less than a very high percentage of control. In addition, the Midwest Fruit Workers (and I think others) rate Avaunt as only Fair for apple maggot control, and several other compounds are rated Excellent or Good. My point ... any weaknesses, even small ones, in the effectiveness of tree-row volume modifications were probably multiplied by pest pressure and a less-than-ideal insecticide for this pest. That said, perhaps something more important in the overall discussion of tree-row volume calculations seems to me to center on the nature of data that support labels and recommendations for newer insecticides. Over the last15 years when I have tested insecticides, the trees that I use are characteristic of modern orchards -- small and well pruned. I determine the amount of water required to give thorough coverage, and that's the spray volume I use (often 100 gallons or less per acre). I determine the portion of an acre represented by the trees in each treatment, and I apply the amount of insecticide on the label (or in the experimental protocol) -- on a per acre basis. I have no illusions that work done in Illinois (not exactly the king of fruit production) determines or dramatically alters national and international labels, but I think most other entomologists test products in a similar fashion -- and pretty much always on small, well pruned trees. One might argue that this means that the per-acre rates on labels for newer insecticides have already been adjusted for (based on) the reduced tree-row volume of small trees. This is entirely different from adjusting the amounts of Guthion or Imidan or other older compounds whose labels may have originated with data from larger trees in older production systems. Those amounts could logically be reduced with the transition to smaller trees over the last few decades, but labels for newer materials such as Avaunt, the neonicotinoids, Delegate, Rimon, Altacor, etc. already reflect the necessary amounts for effective control on today's smaller trees. I realize that there remains a lot of difference in tree sizes in modern production systems, and adjusting spray volume and pesticide rates over those different tree sizes makes sense. Still, as we consider all the expert comments offered on this site over the last several days, it might be wise to also take into account the research basis for the per-acre rates expressed on labels for newer products. Rick Weinzierl Richard Weinzierl, Professor and Extension Entomologist Department of Crop Sciences, University of Illinois S-334 Turner Hall, 1102 South Goodwin Avenue Urbana, IL 61801 weinz...@uiuc.edu, Ph. 217-244-2126
Re: Apple-Crop: Pesticide Rates and Tree Row Volume
Rick: I've been waiting for you to add to the discussion, after our experience with codling moth sprays, etc. Sorry, but no F AND G Notes today. Hope to see you at the Fruit Schools.. Chris -Original Message- From: Richard Weinzierl weinz...@uiuc.edu To: Apple-Crop apple-crop@virtualorchard.net Sent: Tue, Jan 19, 2010 9:45 am Subject: Apple-Crop: Pesticide Rates and Tree Row Volume Hello all. A little context before the main idea about how new insecticides (and other pesticides) are tested in tree fruit crops ... This thread started with a report that Avaunt performed poorly for apple maggot control when used in a spray program that relied on tree-row volume calculations. As a few others have pointed out, this seems to have been a banner year for apple maggot in many areas, so pest pressure likely helped to exaggerate anything less than a very high percentage of control. In addition, the Midwest Fruit Workers (and I think others) rate Avaunt as only Fair for apple maggot control, and several other compounds are rated Excellent or Good. My point ... any weaknesses, even small ones, in the effectiveness of tree-row volume modifications were probably multiplied by pest pressure and a less-than-ideal insecticide for this pest. That said, perhaps something more important in the overall discussion of tree-row volume calculations seems to me to center on the nature of data that support labels and recommendations for newer insecticides. Over the last15 years when I have tested insecticides, the trees that I use are characteristic of modern orchards -- small and well pruned. I determine the amount of water required to give thorough coverage, and that's the spray volume I use (often 100 gallons or less per acre). I determine the portion of an acre represented by the trees in each treatment, and I apply the amount of insecticide on the label (or in the experimental protocol) -- on a per acre basis. I have no illusions that work done in Illinois (not exactly the king of fruit production) determines or dramatically alters national and international labels, but I think most other entomologists test products in a similar fashion -- and pretty much always on small, well pruned trees. One might argue that this means that the per-acre rates on labels for newer insecticides have already been adjusted for (based on) the reduced tree-row volume of small trees. This is entirely different from adjusting the amounts of Guthion or Imidan or other older compounds whose labels may have originated with data from larger trees in older production systems. Those amounts could logically be reduced with the transition to smaller trees over the last few decades, but labels for newer materials such as Avaunt, the neonicotinoids, Delegate, Rimon, Altacor, etc. already reflect the necessary amounts for effective control on today's smaller trees. I realize that there remains a lot of difference in tree sizes in modern production systems, and adjusting spray volume and pesticide rates over those different tree sizes makes sense. Still, as we consider all the expert comments offered on this site over the last several days, it might be wise to also take into account the research basis for the per-acre rates expressed on labels for newer products. Rick Weinzierl Richard Weinzierl, Professor and Extension Entomologist Department of Crop Sciences, University of Illinois S-334 Turner Hall, 1102 South Goodwin Avenue Urbana, IL 61801 weinz...@uiuc.edu, Ph. 217-244-2126 =
