Category: Boom Sprayers

Main category for sprayers with horizontal booms

  • The Ideal Sprayer (an open letter to sprayer manufacturers)

    The Ideal Sprayer (an open letter to sprayer manufacturers)

    Today’s sprayer has to excel at a lot of things. It has to have capacity and low weight. It has to go fast but be comfortable. It needs wide booms that stay level over complex terrain. It has to deliver the right spray volume at the right spray quality for the job. It has to be easy to fill and easy to clean. And of course, it has to be reliable, affordable, and come with dealer support.

    We’ve definitely made progress in many of these areas. But the overall package still leaves lots of room for improvement and doesn’t address some issues that are of importance to applicators. Is it time for a reset?

    Let’s say cost is no object. Here’s where I think the industry could go.

    Focus on spray delivery

    Spraying is done to protect crops. We need to do it without harming the environment while being economical with the inputs. These three tenets make up the Application Triangle, sometimes known as the 3 Es of spraying: Efficacy, Environment, Efficiency. The triangle represents the need for balance. A gain in one or two areas often requires a loss in another. That’s why there has never been a so-called “silver bullet” in spraying.

    Priority 1: Only spray when and where required.  Site specific treatments and IPM have been slow to make their way to the spraying world partly because of the low cost of inputs, but also because of difficulties defining and mapping areas that require different rates or products. The machine learning revolution is changing that. Green on Brown or Green on Green sensing can do more than save inputs. They can generate maps that document the change of weed patches over time, identifying priority areas and threshold densities and flagging problems early.

    Priority 2: Integrate air assist. Air carries small droplets towards the target, protecting them from displacement by travel-induced or ambient winds. Once there, air can improve target interception and retention. It has to be done right, though, as improper adjustment can result in the opposite outcome. The reason it’s high on this list is because it improves efficacy and environmental protection at a modest cost.

    Priority 3: Improve droplet size control.  Nozzle design has improved, but the overall range of spray qualities that is achievable for any specific nozzle remains narrow. Sprays can be made finer or coarser with spray pressure, but this has implications for pattern uniformity. Twin Fluid nozzles currently offer the widest range of spray qualities, allowing one nozzle to do it all. We simply need greater droplet size flexibility on the spray boom.

    Priority 4: Use nozzle-specific rate control.  At minimum, a sprayer needs a system that allows for individual nozzle rate control within a wide window, say 4:1. This allows consistent dosing over a wide speed range, turn compensation, or local adjustments to dose for specific (sensed) canopy conditions. By layering direct injection at the nozzle on top of this, the sprayer can change rate and volume independently. Being able to spray the right amount in the right spray quality at the right volume, where needed completes the opportunity created by pest and canopy sensing.

    Create better infrastructure

    The backbone of the sprayer, the frame, drivetrain, boom, tank, pump, and plumbing, are responsible for carrying and delivering the spray liquid. Poor management of these variables results in an unproductive, heavy machine.

    Priority 1: Prepare booms for future.  A limiting factor in sprayer performance is boom width and stability. Consistent and low boom heights are the cornerstone of good application, ensuring uniform distribution, reducing drift potential, and improving targeting within the canopy. But perhaps as importantly, stable booms are essential for accurate optical spot spraying and any other sensing tasks that will rise in importance. Set a standard for sway, say target height plus or minus 10 cm along the width of the boom, 90% of the time. Do the same for yaw. Accommodate brackets for sensors and wiring harnesses when designing the boom fold.

    Priority 2: Improve plumbing.  Poorly executed sprayer plumbing causes waste and decontamination headaches. Although rubber hoses attached to plastic fittings provide a very versatile and generic building block, they generate and hide countless niches in which pesticide mixtures or active ingredient residue can accumulate. A simplified design that incorporates more engineered stainless steel tubing, smooth directional and dimensional transitions, interior surfaces that don’t accumulate residues and generate more efficient flows – all these would improve many aspects of the spray operation. It needs to be goal oriented – i.e., zero waste in priming and cleaning, guaranteed decontaminated after a rinse cycle. Draining on the ground should not be necessary.

    Priority 3: Save weight. Weight causes compaction and eats fuel. Advanced materials or techniques can save weight while preserving strength. Savings can be applied to capacity. We need to explore advanced materials and trussed or exoskeletal designs (see “Aerodynamics”).

    Priority 4: Consider aerodynamics in chassis and boom design. Wind blowing past a tractor, tank or boom, or counter-rotating air from wheels creates turbulence that displaces small droplets within it, reducing uniformity. Cleaner air makes it easier to use smaller droplets, easier to implement air assist or any other drift-reducing technology. This is no small task, as air can come from any direction. But as units become larger and travel faster, this effect can’t be ignored. Monocoque designs that use aerodynamic exteriors to carry machine weight may provide an answer.

    Provide quality control

    Spraying can be a guessing game, hence the terms “Spray and Pray”. We don’t know the outcome for days or weeks, depending on the mode of action, and by the time the result is known, it is too late to do anything if it’s unsatisfactory. But we can do better in assuring some sort of standard.

    Priority 1: Confirm pressure, flow, and patterns at nozzles. The average sprayer has one flow- and one pressure-sensor. It can confirm the flow of the entire spray boom but cannot do that at the nozzle level. PWM has helped, by inferring flow from duty cycle. But actual liquid flow, and its pressure, remain unverified at the spray tip. A visual inspection of the pattern is necessary, and this is not only impractical but also wasteful and potentially hazardous.

    Priority 2: Characterize canopy. If we knew the crop canopy was dense or sparse, we could adjust the water volume or rate of the product accordingly. LiDAR (Light Detection and Ranging) can characterize the physical structure of an object that would indicate density or porosity for which a dose (or droplet size, or air) adjustment may be necessary. This is not some future technology. The iPhone 12 Pro has it. Even RGB image processing could do something very similar.

    Priority 3: Confirm coverage and drift.  Say we’ve characterized the canopy and adjusted the atomization to suit. Is it having the intended impact? We will need a way to verify that the settings of the sprayer result in the required canopy penetration and coverage, even drift, on-the-go. We would need sprayer-mounted sensors that see spray deposits or an airborne spray cloud. The verification must be fast enough to make corrections during the spray operation. This kind of quality control provides the feedback loop to the first priority, spray delivery. It creates a perfect environment for machine learning and continuous improvement.

    Priority 4: Improve user interface.  The complexity of modern equipment monitors is great if you’re familiar with their features. But if you’re a new user or less comfortable with layers of screens and buttons and warning beepers, navigating the monitor can be a game stopper. Can we have beginner modes? Or a system where the monitor more actively engages with the user, asking questions or reminding a novice of key settings? The friendliness of the interface is a sleeper issue, it seems less important at first look but can over-ride many equipment features because of the power of a positive user experience.

    I challenge sprayer manufacturers to conceptualize and show us the ideal sprayer they’re working towards. The perfect unit may never reach us, as this proposal is rife with technological and cost barriers. But it is nonetheless important to identify priorities and identify possible ways to meet them. As we creep towards the solution with incremental improvements, recall that its not the size of the step that matters, it’s the direction.

  • End of Spraying Season Checklist

    End of Spraying Season Checklist

    It’s finally that time of year to put away the most-used piece of farm equipment, the sprayer. Winterizing is a necessary step, but also an opportunity to do a few extra things.

    Winterizing

    1. Before you do anything, walk around the sprayer and note any telltale signs of liquid leaks. Once washed, the helpful dusty surfaces are gone and slow, chronic leaks may go unnoticed.
    2. Now it’s OK to clean and rinse the sprayer tank and wash the sprayer exterior.
    3. Drain any remaining water from the product and the rinse tanks. These remainders will cause unwanted dilution of the antifreeze. After you drain filter housings, inspect and clean filters.
    4. Choose your anti-freeze. Automotive anti-freeze works, but’s it’s toxic and you can’t spray or drain it on the ground. Liquid fertilizer is sometimes used, but it’s corrosive, crystallizes when cold, and is not recommended. The best product is RV Antifreeze. It’s friendly to rubber and plastic, considered non-toxic, and can protect down to the coldest temperatures. Some dealers carry specific sprayer antifreeze. Don’t use fertilizer (e.g. 28) to winterize – especially with PWM systems.
    5. Add between 25 and 50 gallons of antifreeze to the product tank, or if you have one, to the clean water tank. Most larger sprayers need at least 25 gallons just to prime the plumbing.
    6. If you have a rinse tank, start a normal rinse procedure. Run the product pump, drawing from the rinse tank and pushing the material through the wash down nozzles into the product tank. Once the rinse introduction is complete, an automatic rinse procedure may subsequently open various lines leading to the tank as it swirls the rinse solution through the tank. Familiarize yourself with the specifics of that process.
    7. If rinsing valves are manually controlled, once the antifreeze is in the product tank, run the pump, drawing from the tank and circulating back to the tank via agitation. If you have any other bypass lines, such as sparge, make sure the valve is opened. Run for two to three minutes.
    8. If you have an on-sprayer eductor system, run the antifreeze past it and activate the eductor wash process.
    9. Now, it’s time to push the antifreeze to the boom. Treat this like a boom cleaning, making sure the antifreeze gets to each nozzle body. If you have high- and low-flow options, open them to ensure the bypass gets the antifreeze.
    10. Activate one boom section at a time and ensure all nozzles have received the antifreeze. Open nozzle end caps and allow the antifreeze the push out the water that is trapped there. It helps if you first purge the system with compressed air, then you don’t need to wait for the clear water to gradually change colour as the antifreeze arrives.
    11. For extra points, rotate the nozzles through each position. As with cleaning or servicing, a remote-control boom section controller is invaluable here.
    12. Remember to activate the fence row nozzles if you have any. These usually have their own dedicated feed line coming off the outer boom section.
    13. If you filled your anti-freeze directly into the rinse tank, briefly open the rinse and product tank fill valves to allow anti-freeze to push out any water. Don’t forget the front fill line.
    14. It’s OK to leave any leftover antifreeze in the tank. Next spring, collect it for re-use in the fall. You’ll still need more but this saves you some.
    15. Don’t forget to also winterize your spray tender and any other transfer pumps.
    16. It’s always a good idea to grease fittings after equipment is washed, to displace any water that got in, and to lubricate other moving parts that should be protected from corrosion.

    Inspecting and Reflecting

    You’re going to be looking closely at a clean sprayer, and this is a good time to spend a few extra moments to ponder the big picture. But first:

    1. Inspect the full length of all hoses. Look for kinks, rubbing, small leaks, loose or defective clamps, valves, nozzle bodies. Tighten what’s loose, replace what’s worn.
    2. Check cabin air filter service interval. Most new sprayers have activated carbon filtration that requires regular replacement. Activated carbon starts deteriorating with any air contact, so if you get a new one, leave it wrapped in its plastic until you need it.
    3. Download or record sprayer performance data. How many engine and spraying hours? How many acres? How much water? A typical sprayer may calculate your acres per hour, but uses spraying hours only which paints a rosy picture. Do the calculation using gross engine hours to get a better idea of time lost to idling, transporting. Compare to previous year, perhaps set some goals.
    4. Check with the dealer to make sure you’ve got the latest controller software version. Many systems get an upgrade during the off-season, so check back in the spring.
    5. Remove the flow meter from the system and ensure it runs free. Do not use compressed air to run the impeller, this can ruin it. Simply blow on it and ensure it runs freely. This is an important part of the sprayer, so some people store it separately over winter. Did it provide accurate information?
    6. Top up the fuel tank to prevent condensation.
    7. Don’t forget to mouse-and bird-proof.

    Now:

    1. Think back on the season. What went well? What went poorly? What repairs were needed? Which ones did you put off? Are you happy with your procedures for filling and cleaning? Did you hear or read about improvements that seem interesting? Reminisce by reading the notes you wrote on your cab windows.
    2. Make a list of the improvements that would address the main issues you came up with during your reflection. Is it time for a better filling setup? Do you need a whole tender system, or just an upgraded fill pump or a better inductor? Is it time to add a continuous rinse system?

    Replacements and Improvements

    1. Some sprayer components simply wear out and need regular replacement. A rule of thumb for sprayer nozzles is about 30,000 acres for an average sprayer speed and boom width. But before you buy, make sure you know what you need. Were you happy with the spray performance? Did you have more drift than you wanted, or poor coverage? As our cropping systems change, we may need different nozzles to suit the purpose. Now is the time to think about that very coarse low-drift nozzle that would have allowed you to get the spray on before the rain that delayed you for 3 days. Or the higher volume spray that would have done a better job with desiccating the tall canola crop, speeding up harvest. Or the finer spray that works better with the contact products you need to manage resistance.
    2. Pumps can also wear. An impeller replacement can revitalize a centrifugal pump and give back more pressure and flow. Or a new pump with run-dry seals can avoid downtime from a pump failure in the middle of a good stretch of weather.
    3. We still see plastic boom lines on some sprayers. Replacing them with stainless steel eliminates warped lines and makes spray patterns more accurate, improves cleanout, and adds sparkle.
    4. A wider boom can dramatically increase productivity. After-market booms are available in 135′ and larger widths. Aluminum construction keeps them light, and corrosion-free.
    5. Pulse Width Modulation (PWM) can be retrofitted on any sprayer. This will offer improved sectional control resolution, turn compensation, and better droplet size control.
    6. Spot spraying can be added to any sprayer, and this will save 50 to 75% of pre-seed product use. In the case of WEEDit Quadro, these systems now come with stand-alone PWM that will work for general broadcast spraying in crop, with all the features mentioned above. Trimble offers the WeedSeeker II, it’s also feature rich but doesn’t offer PWM.
    7. Become part of a mesonet. Most crop imaging services and some agronomic service providers offer weather stations, and obtaining one can make you part of a large, high resolution network. Local monitoring of temperature, rainfall, and wind conditions improves spray decisions as well, and may even give you the ability to identify temperature inversions.

    The sprayer will often be the first piece of equipment used in the spring. Preparing it for its next job starts now.

  • Spray and Soil Fumigant Buffer Zones in Canada

    Spray and Soil Fumigant Buffer Zones in Canada

    Spray buffer zones are no-spray areas required at the time of application between the area being treated and the closest downwind edge of a sensitive terrestrial or aquatic habitat. Spray buffer zones reduce the amount of spray drift that enters downwind, non-target areas.

    Sensitive Terrestrial Habitats

    Sensitive terrestrial habitats can include hedgerows, grasslands, shelterbelts, windbreaks, forested areas and woodlots. Crops and private properties adjacent to treated areas are not considered to be sensitive terrestrial habitats and do not require spray buffer zones. However, labelled spray buffer zones are a good indicator of potential damage to adjacent vegetation. Applicators are responsible for ensuring their spraying programs do not adversely affect neighbouring properties.

    Sensitive Aquatic Habitats

    Sensitive aquatic habitats can include lakes, rivers, streams (channelized or natural), creeks, reservoirs, marshes, wetlands and ponds. Temporary bodies of water resulting from flooding or drainage to low-lying areas are not considered sensitive aquatic habitats. Nor are aquatic drainage ditches or seasonal water courses that are dry at the time of application. Water body depth will determine the buffer zone distance, as indicated on the pesticide label. Downslope open water may also require a vegetative filter strip .

    The pesticide label will indicate when a spray buffer zone is required. The distance will depend on the product used, the method of application and the crop being sprayed. In some cases, the buffer zone may be modified using Health Canada’s Spray Buffer Zone Calculator . When provincial and label restrictions differ, or label restrictions differ between tank mix partners, use the greatest distance.

    Buffer zones or No-Spray zones physically separate the end of the spray swath for the nearest downwind sensitive area.
    Buffer zones or No-Spray zones physically separate the end of the spray swath for the nearest downwind sensitive area.

    Spray Buffer Zone Calculator

    Unless forbidden by the pesticide label, Health Canada’s Spray Buffer Zone Calculator may permit applicators to reduce the size of the spray buffer zone specified on a pesticide label. To be eligible, the product label must specify a field or aerial spray quality coarser than “Very Fine” and finer than “Very Coarse”. All airblast spray qualities are applicable.

    Modifications are based on meteorological conditions, sprayer configuration and the application method at the time of application. If modified spray buffer zone distances are less than provincial or municipal distances, use the greater distance.

    Applicators that choose to use the calculator must retain a copy of the summary page for at least one year following the application to demonstrate compliance with label directions.

    Vegetative Filter Strips

    A vegetative filter strip is a permanently vegetated strip of land that sits between an agricultural field and downslope surface waters. Vegetative filter strips reduce the amount of pesticide entering surface waters from runoff by slowing runoff water and filtering out pesticides carried with the runoff.

    Pesticide labels may require a vegetative filter strip, or recommend one, as a best management practice. They must be at least 10 metres wide from edge of field to the surface water body and be composed primarily, but not exclusively, of grasses.

    Spray buffer zones do not apply to vegetative filter strips unless there is a pre-existing sensitive terrestrial habitat within them. Therefore, vegetative filter strips may overlap spray buffer zones when open water is both downslope and downwind (see illustration). In this case, the minimum 10 metres vegetative filter strip distance must be observed, but the set-back can be larger based on spray buffer zone, provincial or municipal restrictions.

    Soil Fumigant Buffer Zones

    Soil Fumigant Buffer Zones are mandatory, untreated perimeters surrounding the treated field. They limit user exposure and increase the protection of workers, bystanders and the environment. The distance will depend on the application method, product rate and field size, as indicated on the pesticide label. An Emergency Response Plan is required when residences or businesses are located within 90 metres of the buffer zone perimeter.

    Soil fumigant buffer zones have a time component. This Buffer Zone Period begins at the start of the application and ends a minimum 48 hours following the application. Respiratory protection and stop-work triggers, as specified on the pesticide label, will apply to anyone present in the buffer zone area during the buffer zone period.

    Buildings and residential areas within the soil fumigant buffer zone must be unoccupied during this period. Unless in transit, non-handlers (including field workers) must be excluded from the soil fumigant buffer zone during this period. Entry is permitted for fumigant handlers with appropriate certification, emergency personnel and local, provincial, or federal officials performing inspection, sampling, or other similar duties.

    Image from www.onspecialitycrops.ca

    Soil fumigant buffer zone signage must be posted within 24 hours prior to the application and remain posted until the buffer zone period expires. Signage must include, but is not limited to, the date and time the buffer zone period ends and the name, address, and telephone number of the applicator. Soil fumigant buffer zone signage must be located at the outer perimeter of the buffer zone, at all entrances to the field, and along likely routes where people not under the owner’s control may approach. Soil fumigant buffer zone signs are in addition to, and do not replace, fumigant application block signage .

    Applicators must develop a written Fumigation Management Plan prior to the start of any application. The plan outlines key steps to ensure a safe and effective fumigation, including site conditions, buffer zones and emergency response planning. Both the owner/operator of the fumigated area and the fumigant applicator must retain signed fumigant management plans as well as a summary of Post-Application Procedures for two years following the application.

  • Three Manageable Factors that Affect Spray Drift

    Three Manageable Factors that Affect Spray Drift

    In 2014 one of our OMAFRA summer students designed a short-and-gritty demonstration using a backpack sprayer, a variable-speed fan and some water-sensitive paper positioned downwind at 1.5 metre intervals. The intent was to illustrate how sprayer operators could reduce the potential for off-target drift by recognizing and accounting for three factors:

    • Apparent wind speed (i.e. the sum of wind speed and travel speed)
    • Boom height (i.e. release height)
    • Droplet size (i.e. nozzle spray quality)

    Apparent Wind Speed

    Spray operators know they should not spray when the air is calm or when the wind is too high, but they often forget that the nozzles experience “apparent wind speed” which means driving 10 km/h into a 10 km/h headwind is essentially spraying in a 20 km/h wind.

    The result of spraying with a Medium spray quality in 10 km/h and 15 km/h wind: water-sensitive papers indicated that there is more downwind drift in higher winds.

    Boom Height

    Spray operators raise their booms to ensure their nozzles clear the crops, but this contributes to off target drift and greatly reduces coverage – particularly when using twin-fan style tips. Dr. Tom Wolf explains how to set your boom height here, or you could watch one of our Exploding Sprayer Myths videos on the subject.

    The result of spraying with a Medium spray quality in a 10 km/h wind at 50 cm and 100 cm from the ground: water-sensitive papers indicated that downwind drift increases as the boom gets higher.

    Droplet Size

    The coarser the spray quality, the less likely the spray will drift off target. Remember, for a given volume, shifting to larger droplets means fewer droplets. Application volumes may have to increase to compensate for potentially reduced coverage.

    The result of spraying with a Medium spray quality versus spraying with an Extremely Coarse spray quality: water-sensitive papers indicated that there is more downwind drift from smaller droplets.

    Take-Home

    This demo used percent coverage as a metric, which is convenient but greatly underestimates drift. So even when the spray window is small and the spray has to go on, take a moment to drop the boom, use a coarser droplet size and if it’s too windy, just don’t spray.

    WUR Drift Calculator

    There are many drift calculators available for home use. Some require more expertise than others to get a reliable result. This free downloadable calculator from Wageningen University & Research was made available in 2021. It can quantify spray drift deposits onto surface waters and non-target terrestrial areas near a sprayed field or orchard

    The calculator uses statistically obtained regression curves to calculate spray deposition next to the sprayed field. The spray drift curves are based on the latest experimental data for field crops, fruit orchards and avenue tree nurseries.

    Download your copy here.

     

  • Controlling Cercospora Leaf Spot in Sugarbeets

    Controlling Cercospora Leaf Spot in Sugarbeets

    Download the 2023 publication from Crop Protection here.

    Cercospora leaf spot (CLS), caused by the fungal pathogen Cercospora beticola, is one of the most damaging foliar diseases affecting sugarbeet (Figure 1) (Khan et al. 2008). Growers rely on broad-spectrum contact fungicides because they are less likely to cause fungicide resistance (OMAFRA 2020). However, these fungicides are usually less effective than other fungicides (Trueman & Burlakoti 2014), and require frequent reapplications (Thind & Hollomon 2018) and good coverage to be effective (Prokop & Veverka 2006; Roehrig et al. 2018).

    Figure 1. Cercospora leaf spot on sugarbeet.

    We evaluated practices intended to improve the efficacy of Manzate® Pro-Stick™ (Mancozeb) by improving deposition and penetration into the sugarbeet canopy. Practices included different nozzle types (Shepard et al. 2006; Dorr et al. 2013), carrier volumes (Armstrong-Cho et al. 2008; Roehrig et al. 2018; Tedford et al. 2018) and the addition of InterLock®. InterLock is a spray adjuvant made with modified vegetable oil (MVO), vegetable oil and a polyoxyethylene sorbitan fatty acid ester emulsifier. It is intended to reduce the number of drift-prone, fine droplets without compromising the volume median diameter (WinField® 2019).

    Research

    In 2019 and 2020, InterLock and carrier volume were assessed to evaluate effects of:

    1. InterLock on Manzate Pro-Stick efficacy at different carrier volumes.
    2. InterLock on spray deposition and penetration within the sugarbeet canopy.

    Objective 1: InterLock on Manzate Pro-Stick efficacy at different carrier volumes

    Four replicated field trials were conducted at two sites, Dealtown (2019) and Ridgetown (2019 and 2020). Treatments were evaluated using four carrier volumes: 115, 235, 350, and 470 L ha-1 (12, 25, 37, and 50 gpa) and applied on a 14-day schedule.

    Results

    • Adding InterLock to Manzate Pro-Stick did not reduce disease accumulation over the season (Figure 2a) or improve beet and sugar yield or sugar quality compared to applications of Manzate Pro-Stick alone (data not shown).
    • Carrier volume did not affect disease accumulation (Figure 2b).
    Figure 2a. Disease accumulation (standardized area under the disease progress stairs; sAUDPS) (±SE) for fungicide treatments applied to sugarbeets in Ridgetown and Dealtown ON 2019, and in Ridgetown 2020. Bars followed by the same letter are not significantly different at p ≤ 0.05, Tukey’s HSD, ns= not significant.
    Figure 2b. Disease accumulation (standardized area under the disease progress stairs; sAUDPS) (±SE) for carrier volume applied to sugarbeets in Ridgetown and Dealtown ON 2019, and in Ridgetown 2020. Bars followed by the same letter are not significantly different at p ≤ 0.05, Tukey’s HSD, ns= not significant.

    Objective 2: InterLock on spray deposition and penetration within the sugarbeet canopy

    Deposition was evaluated using Rhodamine WT dye recovery. The amount of dye recovered for a treatment (µL AI/ g leaf tissue) was used to make assumptions about treatment deposition in the sugarbeet canopy. To assess spray deposition, samples were taken from six canopy locations (Figure 3 and 4).

    Figure 3. Leaf sample collection from sugarbeet canopy.
    Figure 4. Leaf samples were taken from a) three canopy locations 1= inner, 2= mid, 3= outer from b) two leaf locations each A= tip, B= base.

    Three sets of replicated experiments were conducted in Ridgetown (2019 and 2020) to evaluate the effect of InterLock on canopy deposition when 1) mixed with Manzate Pro-Stick, 2) using three different nozzle types, and 3) using three carrier volumes.

    In the first study, four programs (Manzate Pro-Stick + InterLock, Manzate Pro-Stick alone, InterLock alone, and water) were evaluated for dye recovery.

    Results

    • Deposition was improved for the InterLock only treatment compared with water, but when InterLock was applied with Manzate Pro-Stick the deposition was the same as Manzate Pro-Stick applied alone (Figure 5). It is possible that the fungicide formulation or active ingredient had an antagonistic effect with InterLock, though we cannot determine that from this study.
    Figure 5. Effect of program on mean Rhodamine WT active ingredient (µL per gram of dry leaf) (±SE) recovered from six locations in a sugarbeet canopy at the 13 (Trial 1) and 16 (Trial 2) leaf stage in Ridgetown, ON 2019. Bars followed by the same letter are not significantly different at p ≤ 0.05, Tukey’s HSD.

    In the second study Manzate Pro-Stick + InterLock and Manzate Pro-Stick were applied using three different nozzle types at ~40 psi:

    • The Hardi ISO Injet is an air inclusion 110° flat fan that produces a Very Coarse spray quality.
    • The TeeJet XR110 is a conventional 110° flat fan that produces a Medium spray quality.
    • The TeeJet AI3070 is an air inclusion, dual flat fan (30° and 70° spray angles) that produces a Coarse spray quality.

    Results

    • Adding InterLock did not affect deposition and did not alter the performance of any nozzle type (data not shown).
    • Deposition among nozzles did differ, with the ISO injet nozzle providing improved deposition compared to the XR110 and AI3070 nozzles (Figure 6).
    Figure 6. Effect of nozzle type on mean Rhodamine WT active ingredient (µL per gram of dry leaf) (±SE) recovered from six locations in a sugarbeet canopy at the 15 (Trial 3), 18 (Trial 4), and 19-22 (Trial 5) leaf stage in Ridgetown, ON 2019 and 2020. Bars followed by the same letter are not significantly different at p ≤ 0.05, Tukey’s HSD.

    In the third study, Manzate Pro-Stick + InterLock and Manzate Pro-Stick were applied using three carrier volumes: 115, 235, and 350 L ha-1.

    Results

    • The addition of InterLock had no effect on deposition, regardless of carrier volume (data not shown).
    • Deposition increased with increasing carrier volume (Figure 7a). A regression analysis determined a curvilinear relationship between carrier volume and deposition, predicting that deposition would increase with increased carrier volume until a maximum carrier volume was reached (Figure 7b). Many studies indicate that at exceptionally high carrier volumes coverage can be reduced primarily due to run-off.
    • Even though increased carrier volume improved fungicide deposition, increased volume did not improve fungicide efficacy for CLS management (Objective 1 efficacy trials).
    Figure 7a. Effect of carrier volume on mean Rhodamine WT active ingredient (µL per gram of dry leaf) (±SE) recovered from six locations in a sugarbeet canopy at the 20 and 23 leaf stage in Ridgetown, ON 2020 (Trial 6 & 7). Bars followed by the same letter are not significantly different at p ≤ 0.05, Tukey’s HSD.
    Figure 7b. Regression of carrier volume (115, 235, 350 L ha-1) and mean Rhodamine WT active ingredient (±SE) recovered from six locations in a sugarbeet canopy at the 20 and 23 leaf stage in Ridgetown, ON 2020 (Trial 6 & 7). Data analysis was performed on the log normal scale, means and SE presented have not been back-transformed.”

    Canopy location was an important factor in all experiments

    The least deposition was always found in the outer and inner canopy from the base of the leaf, and in the outer canopy from the tip of the leaf (Figure 4), suggesting that these locations are the most challenging to achieve spray deposition. An example from the nozzle type experiment is shown in Figure 8. One of the proposed benefits of InterLock is for improved spray penetration, but in the current study, InterLock did not improve penetration of Manzate Pro-Stick into any of the harder to reach canopy locations.

    Figure 8. Effect of canopy location on mean Rhodamine WT active ingredient (µL per gram of dry leaf) (±SE) recovered from six locations in a sugarbeet canopy treated with InterLock and different nozzle types at the 15-22 leaf stage in Ridgetown, ON, 2019 and 2020 (Trials 3, 4 & 5). Bars followed by the same letter are not significantly different at p ≤ 0.05, Tukey’s HSD.

    Conclusion

    Adding InterLock to Manzate Pro-Stick did not improve deposition in any field experiment regardless of the nozzle type or carrier volume used. Further, using InterLock with Manzate Pro-Stick did not improve fungicide efficacy for CLS management. However, we cannot determine from this study if InterLock would improve deposition, penetration, or fungicide efficacy using other fungicide products.

    Despite findings of improved disease management with the use of larger carrier volume, fungicides are sometimes still applied with smaller carrier volumes of 100 L ha-1 or less (Armstrong-Cho et al. 2008; Roehrig et al. 2018) to save time and reduce the cost of application. In this experiment, increased carrier volume improved deposition but did not improve fungicide efficacy of Manzate Pro-Stick for CLS management. There is the potential that using increased carrier volume may be more beneficial in years with a greater disease severity, and may thus be worthwhile to growers, as has been observed in previous research on Cercospora leaf spot in Ontario (Tedford et al. 2018).

    See the full thesis here.

    This research was sponsored from the Canadian Agricultural Partnership, Ontario Agri-Food Innovation Alliance, Ontario Sugarbeet Growers’s Association, and the Michigan Sugar Company.

    References

    Armstrong-Cho C, Wolf T, Chongo G, Gan Y, Hogg T, Lafond G, Johnson E, and Banniza S. 2008. The effect of carrier volume on Ascochyta blight (Ascochyta rabiei) control in chickpea. Crop Prot. 27: 1020-1030.

    Dorr GJ, Hewitt AJ, Adkins SW, Hanan J, Zhang H, and Noller B. 2013. A comparison of initial spray characteristics produced by agricultural nozzles. Crop Prot. 53: 109-117.

    Khan J, del Rio LE, Nelson R, Rivera-Varas V, Secor GA, and Khan MFR. 2008. Survival, dispersal, and primary infection site for Cercospora beticola in sugar beet. Plant Dis. 92: 741-745.

    Ontario Ministry of Agriculture, Food, and Rural Affairs (OMAFRA). 2020. Vegetable Crop Protection Guide, Pub 838. Sugarbeets. Queen’s Printer for Ontario, Toronto.

    Prokop M, and Veverka K. 2006. Influence of droplet spectra on the efficiency of contact fungicides and mixtures of contact and systemic fungicides. Plant Protect. Sci. 42: 26-33.

    Roehrig R, Boller W, Forcelini CA, and Chechi A. 2018. Use of surfactant with different volumes of fungicide application in soybean culture. Eng. Agr. Jaboticabal 38: 577-589.

    Shepard D, Agnew M, Fidanza M, Kaminski J, and Dant L. 2006. Selecting nozzles for fungicide spray applications. Golf Course Manag. 74: 83-88.

    Tedford SL, Burlakoti RR, Schaafsma AW, and Trueman CL. 2018. Optimizing management of Cercospora leaf spot (Cercospora beticola) of sugarbeet in the wake of fungicide     resistance. Can. J. Plant Pathol. 41: 35-46.

    Thind TS, and Hollomon DW. 2018. Thiocarbamate fungicides: Reliable tools in resistance management and future outlook. Pest Manag. Sci. 74: 1547-1551.

    Trueman CL, and Burlakoti RR. 2014. Evaluation of products for management of Cercospora leaf spot in sugarbeet, 2014. Plant Disease Management Reports. 9: FC009.

    WinField United. 2019. InterLock. [Internet]. [cited 2019 Feb 25].