Main category for sprayers with horizontal booms
This is the second of a series of short, educational and irreverent videos made with Real Agriculture to bring a little levity to sprayer education. Let’s face it – ironically, nozzles can be pretty dry.
Here we enjoy an early morning soy bean scout and a light breakfast of toast as we demonstrate how pressure, droplet size and canopy penetration interact.
This is the first of a series of short, educational and irreverent videos made with Real Agriculture to bring a little levity to sprayer education. Let’s face it – ironically, nozzles can be pretty dry.
This first video discusses what a rate controller can be expected to do, and what it cannot do. Plus, we got to blow up a sprayer in the intro… so there’s that.
I haven’t written a book-report since high school, but I was recently sent a copy of Dr. Jorg Kitt’s “Spraywise – Broadacre Application Handbook” and I was compelled to share. It’s published by Nufarm and is based out of Australia. What a fantastic, easy-to-read book full of excellent spraying know-how.
Am I overselling this?
I am not.
The chapters include:
At risk of copyright infringement, let me share a little of Dr. Kitt’s advice on chemical and target interaction.
“Many chemicals used in agriculture show only limited movement in or on the plant. For surface active fungicides such as mancozeb coverage is critical because the active does not move – it settles where the droplet dries with only limited redistribution properties.”
This is why we suggest coverage is king when applying products that don’t translocate. You can slow down, raise water volume, or as a last resort reduce spray quality (minding the drift and evaporation issues that arise from this choice). But he goes on:
“Many cereal fungicides such as DMIs move only in the xylem (water transport bundles) and therefore can only travel in one direction – upwards towards the tip of the leaf (acropetal).”
So, I admit that as I continue to transition from horticultural spray applications to broadacre work, I have a lot to learn. Something that bothered me when I started looking at fungicide applications in corn was the appalling coverage on water sensitive paper. If any of my vegetable or orchard applicators had such poor coverage, their crops would be riddled with disease… so why was such poor coverage working so well in field crops?
According to this new-to-me information, perhaps the >Coarse droplets were penetrating the canopy, reaching down to impinge on the base of the plant (or splatter up from the soil) where they could re-distribute by moving up through the xylem. It certainly makes more sense to me why such coarse droplets and relatively low volumes can still be efficacious for certain fungicides in field crops. I’ll reiterate – this may be old hat to some readers, but I still have a lot to learn on this topic.
Dr. Kitt shares many digestible, easily-implemented little factoids that make this handbook a must-have for your spray library. Applied herbicide advice, for example:
“…if 50% of the ground is covered with stubble only half the spray volume will hit the soil directly; the other half will strike stubble. To optimise applications in this situation it is important to produce droplets with sufficient velocity to increase bounce and splatter. The applicator should use higher water volumes (70-100 L/ha) and a coarse to very coarse spray quality. In a clean bed spray quality and water volume have little effect. A coarse spray quality and water volumes above 50 L should be sufficient to achieve efficacy.
These volumes are low for North America (Australia uses nerve-rackingly low volumes) but otherwise this is solid gold.
I was fortunate to have someone send me a copy of this handbook. I’ve poked around on-line to try to find a Nufarm-based website where anyone could order a copy, but I was unsuccessful. However, if you Google “Spraywise Broadacre Application Handbook 2nd ed.” you will find a number of dealers that will happily sell and mail you a copy. I won’t share those links here to avoid a bias, but they’re easily found.
So, to summarize, I wanted to make the sprayers101 readership aware of this Handbook. Given the affiliation with an agrichemical company, it’s a bit adjuvant-rich, but it’s chock full of great information and well worth the cost and effort to have a copy mailed to you.
Now I’m going to go back to reading mine.
Sung to the tune of “Dust in the Wind” by Kansas
I close my eyes, only for a moment, and the spray is gone
All my drops pass before my eyes, oh no – a drift complaint
Drift in the wind
All it is is drift in the wind
Same old spray, just a tank of product in an endless field
2,4-D tumbles in the air though we refuse to see
Drift in the wind
All we do is drift in the wind
Oh, ho, ho
Now, don’t hang on, drops don’t last forever, they evaporate
They slip away, and all your money too, in drifter court
Drift in the wind
All we cause is drift in the wind
All we do is drift in the wind
Drift in the wind
Everything is drift in the wind
Everything is drift in the wind
The wind
Biopesticides are a rapidly growing segment in horticultural pest control. While they are often billed as green “miracle cures”, applicators should be aware that they require unique considerations. Issues with lifespan, target specificity, and application technology can all impact their efficacy. However, like any pesticide application, careful planning can minimize wasted time and money.
Typically defined as pesticides derived from “natural” sources, biopesticides contain active ingredients extracted from plants, microorganisms, animals, and/or certain minerals. Given their origin, and the fact that many biopesticides are living organisms (as is the case with most of the microbial-based pesticides), they are often photo-sensitive and quickly break down. This generally means that they need to be re-applied often.
Consideration should also be given to the lifespan of these products during the application. Many have an optimum pH for both the carrier water and the soil, and a limited temperature range outside of which they may not be active. As already mentioned, direct sunlight can quickly degrade many biopesticides, which means they should be applied either early or late in the day. Timeliness is also a factor: efficacy can be greatly reduced if the product is not used quickly – many biopesticide organisms begin to break down as soon as they are tank mixed. Also, be aware that it can be difficult (or impossible) to find suitable tank-mix partners. For example, a fungal biopesticide obviously shouldn’t be mixed with a fungicide. That also leads the applicator to consider their spray program carefully and clean their sprayers thoroughly between applications.
Applicators should understand how each biopesticide is supposed to control (or more likely, supress) pests. Many biopesticides have to be ingested or physically contact the pest. As such, they often need high application volumes to ensure sufficient coverage of all target surfaces. Many are slow to control the pest, so the applicator may mistakenly think the product is not working, and reapply unnecessarily.
Applicators may need to reconsider their current equipment when using biopesticides. If the product has to contact the pest, high droplet density is preferred. This can be accomplished with high volumes, but also with higher droplet counts, and that means smaller droplets. Drift issues aside, many biopesticides are actually living organisms (e.g. nematodes) which might be negatively affected by the small nozzle orifice.
The “Spray Guy”, Dr. Jason Deveau, (Application Technology Specialist with the Ontario Ministry of Agriculture, Food and Rural Affairs) suggests using a nozzle with a larger exit orifice and no pre-orifice to minimize clogging or any potential damage to the microorganisms. Clogging can be further reduced by using a minimum of three levels of filtration on a sprayer. With proper agitation, a tank basket, suction filter at the pump and slotted strainers behind each tip should catch any “chunks”. In-line filters at the boom are also potentially helpful. Each filter, from tank to nozzle, should be filter smaller particles than the last. Cleaning screens diligently and inspecting the effectiveness of the agitation system, should be part of every spray day.
Applicators can account for many of these issues by understanding what the biopesticide is and how it is intended to work. Consider these questions:
Ultimately, an effective application of biopesticides relies on integrated pest management (IPM). Biopesticides can work as advertised when used thoughtfully and appropriately. Understanding the products benefits and limitations will ensure applicators reap the full benefits of these new and evolving methods of control.