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The right order
Mixing pesticides and additives with a proper fit in proper
sequence is crucial for top performance.
You've likely heard the Las Vegas advertising catch phrase,
"What happens in Vegas, stays in Vegas." There's a twist on that line
when it comes to mixing spray solutions. Mixed properly, pesticides, adjuvants,
and drift-reduction additives pass flawlessly from the mixing vat and inductor
into your sprayer and onto your crops. This minimizes field trips and offtarget
movement while maximizing pest control.
What happens in your sprayer tank may not stay that way.
"Anytime you put something in the tank, it changes the dynamics of the
spray solution," says Jim Reiss, vice president of agricultural
chemistries at Precision Laboratories, pictured above.
Remember the old compatibility test of the Mason jar and
kitchen spoon? That's when farmers poured a sample of spray mix ingredients
into a Mason jar and mixed it with a spoon. If the mix mimicked jelly or
curdled milk, that meant it was added in the wrong order or was incompatible.
If the mix and mixing order were right, the ideal form would range from milky
white to clear or translucent. jelly recipe
Nowadays, applicators have swapped the Mason jar for mixing
inductors that convey the mix to the spray tank. Unfortunately, compatibility
testing is a lost art, says Reiss. Too many applicators just dump products into
the inductor with sometimes terrible results. Suppose you want to add a little
zip to glyphosate in order to control some tough weeds in corn while minimizing
drift. Here's the mix and the order of herbicides and adjuvants you pick:
1. Roundup PowerMax
2. AgriStar 2,4-D LV 4
3. Atrazine 4L
4. Border Xtra 8L
Since the glyphosate product, Roundup PowerMax, is the main
product, you'd think that would be the first product in the inductor, right?
"It actually would look OK until you added it to water,
" says Reiss, "Then it would start gelling as it entered the sprayer.
Here is the right order:
1. Atrazine 4L
2. Border Xtra 8L
3. Agri Star 2,4-D LV 4
4. Roundup PowerMax
Adding chemicals separately is also key, since improperly
mixed gelled products clog sprayers. "Inductors are meant to be giant
funnels, not mixing vats," points out Reiss.
What it costs you
Sprayer ownership has many advantages. "That way, I'm
not waiting for someone else to do it," says Scott Church, who farms with
his son, Jared, near Catlin, Illinois. It enables you to get the most out of
good weather conditions for spraying and to shut down during suboptimal
However, sprayer ownership means mixing your own spray
products. That's why the Churches have been working with Reiss and Chad Barnes,
an Illini FS sales representative, to develop better spray mixes and to boost
their spraying season efficiency.
Improper mixes cost time and money. Reiss points to a
Southern Illinois University analysis showing that a day of downtime at a
400-acre-per-day spray rate leads to lost revenues of $9,600. That assumes
2-inch daily weed growth that clips soybean yields by 2 bushels per acre at $12
per bushel. Higher prices mean heavier losses, Reiss adds.
One at a time
It's also important to spray pesticides one type at a time.
"We now have scenarios where people want to mix
herbicides, fungicides, and insecticides together," says Bob Wolf, coowner
of Wolf Consulting and Research, Mahomet, Illinois. "That is something I
That's because each chemical class may differ in optimal
droplet size. A glyphosate and fungicide mix for simultaneously controlling
weeds and early-season diseases may save time short term, but their optimal
droplet sizes won't click.
Glyphosate works best when applied in a very coarse droplet.
This ranges in size from 401 to 500 microns, about the thickness of a staple.
Since it's a systemic herbicide, glyphosate moves through a weed at contact.
That nixes the need for coating the entire plant. Large droplets also aren't as
prone to move off target.
Meanwhile, fungicides are contact pesticides that require
fine droplets to evenly coat and to protect a crop. Although the fine droplets
ensure crop protection, they are also prone to drift. Their width hovers around
150 microns, about the size of sewing thread.
You can't have it both ways. For optimal efficacy and
minimal off-target movement, Wolf advises that you apply each pesticide class
So how do you do it?
Making sure you have the right mix in the right order is
easier with a free app that Precision Laboratories has developed. The Mix Tank 2.0 app works on Android and iPhone
Mix Tank 2.0 has a database of more than 1,100
crop-protection products from over 17 manufacturers, and it continues to
increase in size. The app is designed to assist applicators with the proper
tankmixing sequence and to maintain accurate spray logs for record keeping.
"This tool is easy to use and helps prevent application
problems, saving time, money, and resources, " says Dan Ori, marketing
manager for Precision Laboratories. "Mixing sequence does matter,"
says Reiss. "There's a right way and a wrong way to do it."
Learn how to mix chemical combinations
Jim Reiss gives a mixing demonstration at www.agriculture.com/efficiency.