Category: Boom Sprayers

Main category for sprayers with horizontal booms

Application Recordkeeping: Focus on Environmental Conditions
Note: This article was written by Bob Wolf of Wolf Consulting and Research, and first appeared as an NDSU Extension Service publication. Bob has agreed to reproduce the article on our website.
When applying crop protection products, a good steward is one who can identify and record the environmental factors that may negatively impact making an application; particularly, the possibility of spray drift.
New label language states: “Avoiding spray drift at the application site is the responsibility of the applicator.” A wise sprayer operator must possess the ability to assess the environmental conditions at the field location to determine how best to spray the field, or maybe decide it would be best not to spray that field, or part of that field, at that time. Instruments that assess environmental conditions are available to assist applicators in making good decisions.
Making the correct measurement is the critical first step. Record the information measured to document the application conditions. Quality records help mitigate against any misapplication allegations, such as a drift complaint. Many of the items listed below are based on past legal experiences with applications involving spray drift litigation.
The following guidelines should help you measure and accurately record environmental conditions at the application site.
1- Document any instrument used by recording the manufacturer and model number. Accurate portable weather instruments are recommended. Portable weather instruments are available that log and store data, and aid in auditing and recordkeeping. Some will have Bluetooth/wireless capabilities.
2- Environmental measurements include wind speed and direction, temperature, and relative humidity.
3- At a minimum, record data at the start and finish of the job. Consider more often as conditions change or for a job that lasts over a longer period. For example, make observations when tank refilling for larger fields. Time stamp all observations with a.m., p.m., or military time.
4- Take meteorological readings as close to the application site as possible. Be advised that the weather data received via a smart phone or local weather station may not be accurate for the location being sprayed.
Note the specific location where the measurement was made, such as GPS coordinates, field entry point, field location, etc. Check the label to see if it requires a specific observation location in relation to the treatment area.
5- Make all measurements as close as possible to the nozzle release height (boom height) and in an area not protected from the wind by the spray machine or your body. For aerial applications, six feet is suggested when using a hand held instrument.
6- Record wind speed averaged over a 1 to 2 minute time span. Note the time the observation was recorded. Most instruments give an average over a period of time. Make sure the instrument’s anemometer is facing directly into the wind.
Do not record winds as variable or with a range i.e. 4 to 8 mph – an average gives a better indication of the transport energy. Light and variable winds, where directions may change several times over a short period, can be more problematic than higher speed winds in a sustained direction. Observe any label restrictions on wind speed.
Wind direction requires a similar averaged measurement. Record direction in degrees magnetic from a compass (0-360°). The use of alphabetic characters, i.e., N, S, NW, to indicate wind direction is discouraged. The key for determining direction is to have an accurate assessment method: trees moving, dust, smoke, a ribbon on a short stake, etc. Face directly into the wind and record the direction from which the wind is coming. A ribbon on a stake with the ribbon blowing directly at your body is a simple fail safe approach. Movement of smoke, particularly from moving aircraft, or dust may help determine direction.
7- Record temperature and humidity since they can be helpful in determining temperature inversion potential. It may be advisable to record both temperature and humidity well before and after the application for this purpose. In fact, recording a morning low and an afternoon high would be useful regarding determining the potential for an inversion. Take temperature measurements with the instrument out of direct sunlight. Shade the instrument with your body or spray equipment. This is especially critical if you are trying to assess temperature differentials for determining if an inversion is in place.
8- Be alert to field level temperature inversion conditions which typically occur from late afternoon, can be sustained through the night, and into the next morning. Beware, inversions can start mid-afternoon. Observe conditions such as the presence of ground fog, smoke layers hanging parallel to the ground, dust hanging over the field/gravel road, heavy dew, frost, or intense odors (i.e., smells from manure or stagnant water from ponds are held close to the surface when inversion conditions exist). Inversions commonly occur with low (less than 3 mph) to no wind speeds. Spraying in calm air is not advised. If a mechanical smoker is used note wind direction and smoke dissipation with a time stamp.
9- Note any variances due to terrain or vegetation differences, tree lines, buildings, etc.
10- Initial or sign all recordings to indicate who made the observation(s).
December 21, 2017
Spray Coverage in Carrot, Onion and Potato
This research was performed with Dennis Van Dyk (@Dennis_VanDyk), vegetable specialist with the Ontario Ministry of Agriculture, Food and Rural Affairs.
Prior to 2017, Syngenta introduced the UK to the Defy 3D nozzle, which is a 100° flat fan, designed to run alternating 38° forward or backward along the boom. They prescribed a boom height of 50 to 75 cm, 30-40 psi, and travel speeds of 10 to 14 km/h in cereals and vegetables. Compared to a conventional flat fan, they claimed that the angle and Medium-Coarse droplets promise less drift and improved coverage.
In 2017, Hypro and John Deere began distributing the Defy 3D in North America. Our goal was to explore coverage from the 3D in vegetable crops. We compared the nozzle’s performance to common grower practices in onion, potato and carrot in the Holland Marsh area of Ontario.
Experiment
We used a technique called fluorimetry. A fluorescent dye (Rhodamine WT) was sprayed at 2 mL / L from a calibrated sprayer based on protocols generously provided by Dr. Tom Wolf.
Tissue samples from the top, middle and bottom of the canopy were collected from random plants.
The samples were rinsed with a volume of dH2O and this rinsate was then tested to determine how much dye was recovered.
The tissues collected were dried and weighed to normalize the samples to µL of dye per gram dry weight to allow for comparison.
In addition, we used water-sensitive paper as a check in key locations in the canopy to provide laminar and panoramic coverage. Papers were digitized and coverage determined as a percentage of the surface covered.
In carrot and onion, we compared a hollowcone, an air-induction flatfan, and alternating 03 3D’s at 500 L/ha (~40 cm boom height, ~3 km/h travel speed, ~27ºC, 3-9 km/h crosswind, ~65% RH).
In potato we compared the alternating 05 3D’s to a hollowcone at 200 L/ha (~55 cm boom height, ~10.5 km/h travel speed, ~22ºC, 6-8 km/h crosswind, ~65% RH).
Water-sensitive papers were originally intended as a coverage check, and not as a source of analysis, but their use revealed interesting information. The following images are the papers recovered a single pass in each crop.
Carrot
Onion
Potato
Results
The following table represents the percent coverage of these paper targets. Papers were digitized using a WordCard Pro business card scanner and analysis made using DepositScan software. This table is small, but you can zoom in for a quick comparison. The following three histograms show the same data graphically for carrot, onion and potato, respectively. Remember, this only represents a single pass, so don’t draw any conclusions about coverage yet.
Carrot
Onion
Potato
It was interesting to note differences in coverage observed on the papers versus the results of the fluorimetric analysis. It was anticipated that while water-sensitive paper serves for rough approximation of deposition, fluorimetry would be far more accurate. This is because of the droplet spread on the paper, and the evaporation and concentration of a spray droplet en route to the target. Again, here is a small table, and again, the next three histograms show the same data graphically for carrot, onion and potato, respectively.
Carrot
Onion
Potato
Observations
While water-sensitive paper is an excellent diagnostic tool for coverage, fluorimetry allows for greater resolution. The high variability in coverage meant little or no statistical significance, however the means suggested the following:
- In carrot, the 3D deposited more spray at the top of the canopy.
- In onion, the hollowcone spray had a higher average deposit, and penetrated more deeply into the canopy.
- In potato, the hollowcone deposited more spray at the top, with little or no difference mid-canopy.
Each nozzle performed well at the top of the canopy, which is quite easy to hit. Certainly they exceeded any threshold for pest control. With the possible exception of hollowcone in onion, nozzle choice had only minor impact on mid-bottom canopy coverage. And so, if coverage is not a factor for distinguishing between these nozzles, we should consider drift potential. Due to the comparably smaller droplet spray quality, the hollowcone is far more prone to off target movement. This leads us to select the AI flat fan or the 3D as the more drift-conscious alternatives.
Future analysis would benefit from a larger sample size to reduce variability, and the inclusion of an air-assist boom to better direct spray into the canopy.
Applitech Canada (Hypro / SHURflo) is gratefully acknowledged for the 3D nozzles. Thanks to Kevin D Vander Kooi (U of G Muck Crops Station) and Paul Lynch (Producer). Assistance from Will Short, Brittany Lacasse and Laura Riches is gratefully acknowledged. Research made possible through funding from Horticultural Crops Ontario.
November 6, 2017
The Vermorel Nozzle – Humility in the Face of History
It’s a rainy Friday in 2017 and I decided to deal with the articles, factsheets, manuals and other sprayer-related documents that have been piling up on my desk for a year.
My filing strategy is based on some advice I got from Dr. Bernard Panneton (Application Tech Guru) back in 2009. He said to read each document and then file them according to content, not by author or date. That way when I need something, I can search up the subject and find everything that might be relevant. More than 1,200 files later, the system works. No Dewey Decimals in my office, thank you.
What I’ve noticed as I sift through this eclectic pile of wisdom, is that many of the application methods I experiment with, or generally promote, are rarely entirely novel. Crop protection has evolved considerably (think pulse width modulation, crop sensing and remote piloted aerial application systems), but the fundamentals of spraying haven’t changed that much.
Case in point.
I just found a photocopy of a 1906 book called “Ginseng – It’s Cultivation, Harvesting, Marketing and Market Value, with a Short Account of Its History and Botany“. Great title. We obviously appreciated florid language in technical manuals 100 years ago. Here’s an excerpt that caught my eye:
“When applied to plants, the finest nozzle obtainable must be used. The Vermorel is perhaps the best. Now make no mistake: this spray must be a spray, not a dribble, nor a drizzle, nor a squirt, but a mist. It must look like a little fog at the end of the hose and must reach every part of the plant, particularly the undersides of the leaves, mind, just enough so it won’t trickle off.”
Poetry. And to make my point, it’s similar to what I’d tell a ginseng grower today. Granted, I’d lead them into a lower-range-of-Medium droplet size and help them achieve the described coverage using drop arms. But what on Earth is a “Vermorel nozzle”? That’s not one I have in my motley collection.
I turned to Virginia Tech’s Museum of Pest Management. I hope they’ll forgive me for lifting their content, but it’s too wonderful not to share. They note the contributions of Charles Valentine Riley. Born in London, England in 1843. He was a multi-talented Renaissance man. He was a pioneer of entomology in the United States and is often referred to as the founder of biological control in America.
Charles Valentine Riley
Two of his greatest contributions to pest management included founding the field of biological control and the invention of the Riley spray nozzle (1889). The Riley nozzle was sold as the Vermorel nozzle. It produced a fan pattern and was the primary nozzle used in pesticide application in the United States and Europe well into the 20th century. The auspicious Mr. Riley died in a bicycle accident in 1895.
The Vermorel nee Riley Nozzle
It was Riley’s nozzle, and the invention of some other early European pesticide application devices, that inspired W.B. Alwood (publisher of orchard spraying techniques c.1899) to import these devices and adopt them to Virginia conditions. The rest is history.
I tell you this because of what I found beneath the book touting the Vermorel; A 2015 TeeJet brochure for their TXVK hollow cone nozzles. I’m aware that the engineering behind the TXVK molded poly body and ceramic orifice is considerable compared to the humble Vermoral. But on closer inspection the fundamental designs aren’t so different. That realization both surprised and pleased me and compelled me to write this article.
I’m not certain what my point is. I suppose it’s just good to be reminded that the next time you want to invest time, money and effort into a “new idea” you might consider a little historical research. Odds are, you’re not the first person to recognize the problem, or propose a solution. A little time in the archives also instills respect for those that were there first. Let’s not waste time repeating their efforts, but stand on their shoulders and advance what they’ve already pioneered.
And if anyone has one of Riley’s Vermorel nozzles, I’d love to add it to my collection. Drop me a line.
August 23, 2017
The Misplay of our Generation
We tend to overestimate the effect of a technology in the short run and underestimate the effect in the long run.
–Amara’s Law of Computing
We tend to overestimate the effect of a stewardship mistake in the short run and underestimate the effect in the long run.
–Wolf’s Adaptation of Amara’s Law to Agricultural Stewardship
August 9, 2017
Since June of 2017, we’ve been hearing reports of widespread dicamba damage symptoms in soybeans throughout the US mid-south and midwest. It appears that millions of acres could ultimately be affected, and yield impacts are unknown at this time.
For those new to the issue, dicamba is a broadleaf herbicide in the Group 4 mode of action group, a benzoic acid. It’s an important tool for herbicide resistance management for weeds like palmer amaranth (Amaranthus palmeri) and waterhemp (A. tuberculatus), populations of which have become resistant to Group 2 (ALS inhibitors), Group 5 (triazines), Group 9 (glyphosate), Group 14 (PPO inhibitors) and Group 27 (HPPD inhibitors) in some places.
Dicamba is a volatile herbicide, discovered in 1942 and first registered in the US in 1967. Its primary use was in corn and other cereal crops, lawns, and rights of way, at comparatively low doses, and relatively early in the season.
Calling a pesticide volatile means it can evaporate after application, either from a liquid or a dry deposit, for hours or sometimes days after application. The resulting vapor cloud can move unpredictably, depending on atmospheric conditions, and affect plants long distances away. Higher temperatures increase vapor loss.
Starting this year, dicamba-tolerant soybeans and cotton (Xtend varieties) were sprayed with new lower-volatility formulations of dicamba, XtendiMax, Engenia, and FeXapan, to control certain broadleaf weeds (including the Amaranth species above) without harming the soybeans. Problem is, dicamba can harm non-Xtend soybeans and other plants, even at very low doses. And these registrations were for applications that occurred later in the season, at higher doses than before.
I usually don’t get involved in people’s decision about whether to spray, or what to spray. But I do get involved when it comes down to how to spray. That’s my job. The real question to me is “can this product be used safely in cotton and soybeans?” Right now, the jury’s out on that one.
In my business, our guiding principles are what some people have called the “Three Es of Application”, Efficacy, Efficiency, & Environment.
We use sprays to control pests. That’s the only reason. We have to apply them so that they work, or else it’s a wasted effort. That’s the efficacy part. We also need to use our resources, time, money, etc., efficiently so the whole process doesn’t bankrupt us and we have time left for other important tasks. That’s efficiency. And finally, we need to protect the environment, and that means making sure the product lands where it’s intended.
None of these three priorities trumps the others. All need to be met to the best degree possible. And due to ever-changing conditions, we will typically change our approach to emphasize one or two of these three over the others, to have a working system.
Simply put, pesticides belong on target surfaces covered by the swath of the sprayer, and nowhere else. If they do move elsewhere (something we’ve come to view as inevitable), regulators conduct risk assessments to ensure that this movement does not result in harm. If harm is possible, mitigating tools such as application timing, product rate, spray method, and buffer zones may be imposed. If those tools aren’t enough to ensure safety, regulators deny product registration. That’s their job.
But even if no harm is done by trespass, the products still need to be on-target. That’s stewardship. It’s a principle whose adherence gives license for a technology to be used. It gives others faith in our competence. Practicing this principle when it’s easy prepares us for hard times.
I respect our regulatory process, and know it to be increasingly conservative with regards to risk the less data there are. I worked for the PMRA (the Canadian pesticide regulatory agency) as an application expert for five years. I know the system isn’t perfect and can make mistakes. I know the system can be political. Usually it’s by being too careful. With dicamba, it looks like the opposite happened.
The reason we’re seeing dicamba leaf cupping everywhere isn’t because all applicators suddenly forgot how to spray. They didn’t suddenly get reckless. They didn’t wilfully ignore all the training that the dicamba manufacturers and state and provincial governments developed in preparation for the product launch.
Instead, dicamba drift reports arose from a combination of extreme sensitivity and easily identified symptoms, as well as an unexpected (by some) amount of vapor drift. Even good applications appeared to create problems. Despite warnings from local experts, regulators and registrants didn’t see it coming.
Experienced agronomists have suggested that the observed dicamba trespass of 2017 implicates both temperature inversions and vapor drift. And although the new product labels advise against spraying under inversion conditions, they don’t say a word about vapor drift, the conditions that give rise to it, or how to protect against its occurrence. Not one word. I’ve searched the Xtendimax, Engenia and FeXapan labels. Nada.
Seems that the regulators and registrants felt confident enough in the reduced volatility of dicamba, based on their internal empirical data and modeling, that they didn’t need to mention it on the label. Calling that a mistake is an understatement.
I’d call it the biggest spray application misplay I’ve ever seen.
A part of the problem may be the enormous scale on which this new use of dicamba was introduced, over 25 million acres of Xtend crops. Scale-up errors are common in many industries. Emergent properties related to scale can’t readily be predicted by empirical data and models. Especially when the underlying data are scant.
So what to do? The continued success of agriculture depends to continued access to safe crop production tools. Irresponsible use threatens that. And by irresponsible use, I don’t just mean application. I also mean registration, promotion, sale, and support. The whole stewardship package.
When problems occur, we need to be quick on our feet to acknowledge them, to support those affected, and to try to understand the cause and prevent the situation from continuing or getting worse.
The current industry response appears to be the exact opposite. What I’ve seen is full of denial, downplaying, innuendo, blaming, and entrenchment.
Why is such an important issue in pesticide stewardship handled so poorly?
The immediate victims of this situation are the producers that depend on new technologies. But the long-term victim is agriculture as a whole. The lack of humility and leadership by many of the proponents of this technology, those with no small financial stake in its continued use, hurts not just them, but all of us involved in farming. This is not stewardship. It’s not license. It’s short sighted and reckless.
Over my career, spray application has generally become safer for the operator and the environment. A big part of our success has been the adoption of low-drift nozzles, the de-facto standard for modern pesticide application. The development of less toxic and less persistent pesticides has also been very important. We can avoid a lot of problems with good chemistry. I’ve been proud to tell this story.
I want to stay proud of our story. And in this case, that requires admitting to mistakes that were made and taking corrective action that is in the best interest of our entire industry. Agriculture will persist longer than company brands and titles. It takes priority.
It’s still too early to fully understand all the reasons for the widespread dicamba damage. But it’s not too soon to say that much of this could have been prevented with a smaller rollout, with greater collaboration with government and university experts during registration, and with more honest information on dicamba volatility on product labels. Call it Volatility Humility.
We’ll all pay for the mistakes that were made. We’ll likely have more stringent and expensive registration protocols. More restrictive application parameters. Strained relationships. More distrust of agriculture.
And as always, an ounce of sweet prevention would have been much better than the pounds of bitter cure that will surely be required to make this right.
August 9, 2017
Plumbing Projects That Make Spraying Easier and Safer
Some of our biggest struggles in spraying involve the start and end of each spray day.
When starting a new field after the sprayer is cleaned, we need to prime the boom. If it’s full of water, that water has to be purged and the question is always for how long and where to do this (pro tip at bottom of article).
At the end of the day, we should ideally clean the sprayer. During that process, we may struggle with waste disposal, including large rinsate amounts, and course, the uncertainty of whether the job is actually done (since clean water looks exactly the same as contaminated water).
If not cleaning the entire sprayer plumbing, we should at least rinse the boom, even if we’re returning to the same product the following day. It can prevent future problems.
These tasks are complicated by the increasingly convoluted plumbing featured on modern sprayers. Ask someone to explain their sprayer’s plumbing system to you one day. It’s a long story! A bright spot is the well-engineered, compact, and accessible Agrifac system.
Fortunately, virtually any sprayer can be modified to suit your needs. Let’s talk about a few ideas for a winter project:
1. Boom flush. It’s good practice to flush clean water through your boom at the end of spraying even if the main tank remains full of product. Some sprayers have an air purge system to eliminate liquid from the plumbing and that is a great feature. A water flush should follow that purge so that any residual pesticide is diluted and removed before it can dry on and become hard to remove later. First you’ll need a clean water tank on the sprayer (150 gal is enough). Second, plumb a feed so that this clean tank can be the sole source of the water supplied to the solution pump. Select this source, shut return lines down or off, and pump clean water through boom. Sprayers that have an auto-rinse cycle will likely be able to draw clean water, but may not be able to push it to the boom, directing it to the wash-down nozzles instead. Check to see what’s possible, and make the changes you need.
2. Clean water pump. Installing a second pump dedicated to the clean water tank has several advantages. We’ve talked about continuous rinsing before, here, and here, as a way to dilute the tank remainder faster. It requires installation of a second pump dedicated to clean water. Additionally, give this pump the option to deliver water to the boom, not just the wash-down nozzles. Now it can be used to rinse water through the boom. The main challenge is to obtain a pump capacity that can match the needs of the boom and/or the wash-down nozzles.
3. Boom ends. We’ve mentioned this part of the boom many times. Boom ends must be flushed regularly to get rid of product and possibly debris that gets stuck there. A simple way to achieve this is to use the Express Nozzle Body End Caps from Hypro. These bleed air continuously, and also prevent accumulation of dead-end contamination. They do need to be flushed, and this can be done by pulling a plug or rotating the turret to an open (no nozzle ) position.
1. Recirculating boom. This is a significant change, but worth considering. Conventional plumbed booms are separated into five to 13 sections. Each has two ends at which the spray stops and where air and contamination can accumulate (see point #3). Each section feed has a shutoff valve. Once the spray mixture leaves the pump and bypass valve, it is committed to leaving the sprayer. In a recirculating boom, the boom becomes a part of the tank and the liquid can return to the tank if desired. Spray is pressurized at one or both ends, and valve positions determine its flow. Sectional control is achieved with individual nozzle shutoff, air or electric.
  1. Three advantages:
    (a) the boom can be primed with new product without spraying. The surplus goes back to the tank.
    (b) the boom can be flushed with water without spraying while material is still in tank, and without spilling anything on the ground. Again, the surplus goes back to the tank.
    (c) high resolution sectional control with individual nozzle shutoff is a byproduct of this design. Fast response, high res, saves money.
2. Steel lines. Steel cleans easier than plastic, and this material makes a lot of sense for booms. But it also makes sense for the boom feeds, currently handled by black rubber hose. This hose is a literal black box. We can’t see inside it, and we don’t know if and where potential contamination resides. It has considerable surface area. Consider replacing portions of your feed lines with steel. The boom is the obvious candidate. Aside from easier cleanout, it also helps with faster nozzle shutoff because it doesn’t expand with pressure.
A word about dumping the tank on the ground. It’s a bad practice for many reasons. Let’s examine just one of those. When you spray a product at 10 gpa, you actually cover each square meter with about 10 mL, or 1/3 oz, of spray mix. When you flush your boom ends on the ground, you’re probably dropping 2 or 3 gallons in the same area. That’s 1000 times the label rate at each boom end, 10 to 26 times per boom. If you dump your tank remainder and all the hoses, say 20 or 30 gallons, that’s 10,000 times the label rate if it covers 1 sq meter. That’s leaching, runoff, residual potential, and not a good story.
Many of the changes we outlined above help prevent that from being necessary.
Pro Tip: To find out how much water your plumbing (from the pump to the boom ends) holds, do this: After cleaning with water and before spraying an EC formulation (white milky appearance in tank, some crop oils are ECs) reset your sprayed gallons on your rate controller. Start spraying and watch for the last nozzle on your furthest and longest section to spray white. Stop spraying and check your sprayed gallons. That’s your volume. No matter the size of nozzle or application volume, it stays constant. To be sure the boom is primed with a new mix, spray until those gallons are reached and you’re set.
July 6, 2017