Thresholds in Crop Scouting

 We are quickly entering the spring season, when planting is on the mind, and we start thinking about weeds and pests. Our anxiety rises when considering treatment options for the critters out there who want to eat or crowd out what we are trying to grow for our livelihood.  I thought it was a good time to review just why it is a good idea to have a professional out there looking at your fields, and why, sometimes, they don't recommend doing anything, even when you think you see something that worries you.  Read on! 

Thresholds in scouting

Why we don’t always treat when we see a problem

When I scout a field, I look for anything out of the ordinary during the growing season.  Each part of the season brings a new set of challenges.  Early on, there are weeds to consider, emergence problems, and seedling diseases.  Later in the season, I look for nutrient deficiencies, insect feeding, and root and foliar diseases.  I look for damage from wind and drought. 

When I do see something that is out of the ordinary, I don’t always recommend acting on it.  I’m not just looking at insects for the opportunity to spray insecticides, and I’m not going to tell the producer to find a fungicide whenever I see a disease. 

Why is that? 

There are several reasons. 

First, there isn’t always something we can do about the problem.  For example, if there’s a water shortage or a drought in a dryland or rainfed field, I can note the leaves curling and plants wilting, but there’s no pivot to turn on.  All we can do is hope for rain.  In another case, there’s a relatively new pest haunting soybeans in my area called the soybean gall midge.  We have a couple years of research on this the little fly-like creature, but the adults spend their time in the ditches and woods surrounding the fields and only come into the fields to lay their eggs.  Once they hatch, the larvae, which are barely visible to the naked eye, quickly find cracks in the stems to hide away, burrowing into the interior of the plant.  Neither the adults nor the larvae would be affected by an insecticide treatment in the field—the adults aren’t in the field for very long, and the larvae are too well protected by their burrowing habits.  So alternate and preventative treatment considerations are being discussed.  For now, we observe and report. 

Second, it isn’t always the right time of the year to treat the problem.  I recently saw some corn plants with yellow whorls and interveinal chlorosis.  This definitely could be the sulfur we had yet to apply to the field, but more likely it was due to a pH problem.  When the plants are in the field, it isn’t the right time to be applying lime to correct the pH.  So, again, we can apply the sulfur, but have to schedule the lime for after harvest in the fall or next spring before planting.  Alternately, the problem could be larvae that had eaten their way through much of the vegetation, but most of them were already in pupae—they won’t be eating anything as adults, so it doesn’t warrant treating pupae who won’t respond to the insecticide.  Also, just because you see evidence of feeding on plants, doesn’t mean you see the critter that has been feeding on them—you may be treating a critter that isn’t even there anymore. 

Third, the problem isn’t always at the economic threshold to be able to warrant treating the problem.  No field is going to be perfectly pest-free, and no plant is going to be perfectly free of some sort of feeding or disease.  Universities come out with what they call “economic thresholds”, or the point at which a pest is going to create enough harm to the plant that yield will be adversely affected, and the extra expense of treating the field is worth it.  Not only are you paying for the chemical, but there’s the application fee if someone else does the application, and equipment cost, fuel, and time spent driving in the field if you do the application yourself.  The potential income from yield lost has to outweigh the cost to treat the pest.  In the case of insects, it may be number of insects per plant or amount of total feeding on the plant (percent of defoliation), in which every leaf on the plant is considered for total loss.  In the case of diseases, it may be percent of the field affected by the disease or number of lesions on each plant. 

Sometimes, scouting a field is more of an art form than a cut and dry numbers game.  Just because you see the critter out there—or even the evidence of it, doesn’t automatically mean there is something that can or should be done about it.  But that also doesn’t mean you shouldn’t be out there watching things grow, and keeping an eye on things.  Because the moment that threshold is crossed, and the season is right, timing is of the essence.  It helps to have someone that knows what they are looking for, and knows what they are looking at. 

It helps to have someone outstanding in the field.  [Yup.  I had to throw that pun in there.] 

Who’s looking out for your crops?

Thanks for reading.

Julie S. Paschold

originally written June 16, 2020

repost April 17, 2023

Danger: Don't Drink This

 

Danger: Don’t Drink This

or How stupid are we?

Responsibilities in wise chemical use

This is a repost from early 2020, when RoundUp was facing lawsuits.  It is still a good read today, about being smart when using chemicals, or anything that could possibly damage you.  My son and I had a good conversation about pocket knives last night.  A pocket knife can be used as a tool for many reasons (a good agronomist is never found without one), but it could also be used as a weapon, so they are banned from some college campuses and in your carry-on in airports (I found that one out the hard way). It is also a good laugh about the silly warnings companies put on their labels. It will make you go out looking for more.

I was minding my own business, chilling in my living room with the television on.  I frankly don’t pay much attention to the “boob tube”—I’d rather be doing something like reading, sketching, walking, putting together a puzzle, talking to my kids, or making up horrible puns with my dad.  

[Okay, I have to interrupt this blog for a good one: my parents were on vacation, walking along the beach, counting jelly-fish.  Being a midwesterner, I had no idea that they just wash up on the shore and lay there on the sand, so my dad took a photo of one and sent it to me.  His caption:  “A picture of the marmalade-fish”.  Ha.  Here’s the little guy now (the fish, not my dad): 

So I responded—“If you see any with a guitar, I guess it would be a jam-fish, then, wouldn’t it”.  Double Ha!  …Come on, didn’t I at least make you groan?]

Back to our regularly scheduled program.  I’m barely paying attention to the channel, glance up, and there’s this lady with GIGANTIC eyes telling me that I quite likely am on my death bed if I’ve even come near the weed killer RoundUp, and need to call her number immediately to be connected to a lawyer who can include me in a lawsuit for damages, but I need to call NOW because there’s no time to waste!  [Frankly, her scary face is what might lead me to my death bed—there’s so much make-up on there and her eyes are pasted so wide open, I thought the color in my TV screen had gone wacky!]

If any of you have watched or read any news, chances are you have heard about EPA’s recent reexamination of studies related to the active ingredient in RoundUp, glyphosate, and whether or not it causes long term health problems.  The latest decision from EPA is that, if used as labeled, there is NOT proof that glyphosate causes cancer. 

But people are still scared—and skeptical.  The ad I saw is one example of how lawyers play on that fear, and the line between facts and rumors becomes hazy. 

This got me thinking.  I agree labeling, restrictions, studies, research, guidelines, and regulations are all very helpful and absolutely needed when using any sort of chemical anywhere.  If we didn’t have guidelines on rates, times of day, temperatures, wind speeds, cautions to stay away from wildlife habitats and being aware of those cute little honeybees, we’d be in trouble.  And the definition of chemical can be so loosely and diversely applied, that it’s a subject for another debate altogether.  However, where do we draw the line between putting the responsibility on the chemical manufacturer and using our own common sense when utilizing their product? 

Remember the woman who sued McDonald’s when she burned her skin spilling coffee on herself?  How silly was that—you ordered coffee, coffee is hot, you spill coffee, hot coffee can hurt.  Common sense, right?  Why does there need to be a warning label for a natural consequence that an average person would understand?  Have you ever read the warnings in the fine print on some other products?  For example, on my sleeping medication, it warns me “may cause drowsiness”—well I should hope so!  That’s why I’m taking it!  And on a department store stroller, in order to not forget your child is in there—to place something valuable in the stroller as well, so you don’t forget to remove your child [Um, isn’t your child probably the most valuable asset you have?]  On skin creams, to not ingest.  On carpentry drills, to not use as a dental drill.  Or the advice to not eat those little silica gel packets [but they look so yummy!].  On saws, to not grab the blade when it’s running.  On thermometers, to not use it orally once you’ve used it rectally [ewwww].  Reminders to not operate machinery while unconscious or sleeping [I didn’t even know that was possible].  The fact that the manufacturers had to put these specific warnings on their products is an indication that someone has actually tried it at some point in time.  Blows your mind, doesn’t it. 

Back to our herbicide.  I’m not saying there isn’t proof that glyphosate doesn’t cause cancer at all in any circumstance.  But just because using glyphosate as labeled doesn’t cause long term health problems doesn’t mean I’m going to put it in my morning coffee or bathe in it.  Any chemical intended to kill something isn’t meant for us to breathe in or be exposed to in large quantities—isn’t that common sense as well?  Obviously not, because Bayer is still facing lawsuits.  I talked to a gal last night who used to work for a tree nursery.  She told stories about how they would get phone calls about people calling about their sick trees, and come to find out the individuals had sprayed weed killer around their actively growing trees.  [You didn’t think about the fact that a tree is a plant?  And weed killers are designed to kill plants?]   

The public scare is growing to the point that Bayer is considering removing RoundUp as a product available for private users.  So no more spraying your rocks or driveway or garden with glyphosate.  I understand the scare about chemicals causing health concerns, but I also understand the move towards taking the chemical away from the common citizen.  It’s better to be safe than sorry, and prevent more people from ending up like the gal that spills hot coffee on her lap and can’t believe she got hurt. 

I guess sometimes even a warning label can’t fix things. 

 

Thanks for reading!

 

February 25, 2020

Julie S. Paschold

Slo-Mo Soil

 Originally Written May 15, 2020, during a time of ample water.  Rewritten December 31, 2022, for our drought situation. 

Slo-Mo Soil

 

One of the world’s greatest resources moves at its own pace.

When I worked in Wisner, I would drive a half hour one way down the same highway.  During that time, Nebraska raised the speed limit on many of the highways, theoretically lowering the amount of time needed to spend on the road on your way to your destination, but also increasing the chances of something not-to-pleasant happening.  It seems that as time passes, so does everyone’s insistence upon going faster.  As the character Brooks found in the movie The Shawshank Redemption when he was released from prison, the world has progressively got itself into a hurry. 

We also don’t want to wait.  Fast food, instant drinks, guaranteed delivery times, drive-up services, overnight orders, no appointments needed.  We call the postal service “snail mail” because it isn’t electronic, and who writes a letter by hand anymore?  Speed and online dating have been available for years.  Technology does everything now—there’s even an app available for crop scouting.  Too bad it can’t actually walk out there and tell you what’s wrong with your crop. 

Some of the best things aren’t created overnight, though.  There’s nothing like a well thought out, hand-written card sent by mail, addressed to only you, your name written in ink on the envelope.  And although you might meet someone online or via a quick date, can you really get to know them in one date?  It takes time to know someone.  A good wine must age.  So must a good personality. 

 

Soil knows this, too.  It takes a LOT of time to create soil in the first place.  Soil comes from a “parent material”, which is ancient windblown, rain-washed, weather-worn, and time-stamped minerals and materials.  We’re talking eons here.  It takes so long, we consider soil one of our limited resources: because we can’t recreate it in our lifetime. Or several lifetimes.

 

Organic matter content in soil is related to many positive qualities—including aggregation, water infiltration, water holding capacity, soil structure, biological processes, long term nutrient content and capacity, and yield response.  Organic matter is a mix of decomposing manure and plant material, earthworm casts, microbes, invertebrates, and humus.  It takes time to build.  Years, in fact.  You can’t just dump some manure on a field, wait a year, and expect organic matter to jump up significantly.  Soil takes time.  It’s not in a hurry.  You can’t honk a horn at it, flip it off, pass it in the passing lane, or tail it bumper-to-bumper.  It will still take its own time. 

That manure you applied and that old plant matter and those dead critters (microbes, invertebrates, insects, arthropods) in the soil will eventually break down and change into that lovely organic matter to help you out.  It takes chemical and physical reactions that we can’t rush—and we can’t duplicate, either.  We have to feed the system, and create the right circumstances to allow the processes to happen.  But it will happen. 

 

There is a difference between surface and ground water.  Since groundwater is held in the ground, and soil is the ground, recharging or a change in groundwater takes a long time to show up as well.  Recharging the groundwater from the drought of 2012 was just regaining strength in 2020; groundwater levels were rising until our current drought situation, which depleted it considerably.  And the crazy weather we had in 2019?  That was mostly surface water changing through flooding.  In years we have extra surface water: give it time, and extra water hanging about in the surface trickles down into the groundwater, too, and we’ll have more of it in stores—if it doesn’t all run away first.  But it will be accounted for.  Soil just takes time. 

Soil isn’t one big block of solid mass—there are very small “holes” in it, too, and that’s where the air and water are held.  Gradually, the water on the surface travels down to the storage area—the groundwater.  Little by little, if it isn’t used right away for another part of the water cycle, water drops from one “hole” to the next via gravity and osmosis until it is collected into the aquifer.  Then it can be stored until needed later.  That’s a good thing, right?  It just takes time.  Which soil knows it has.  There’s always time for soil.  We as humans just don’t think we have any. 

 

Perhaps we need to take a page out of soil’s instruction book and learn to wait a bit.  What’s another couple of minutes, of hours, of weeks, of years? 

After all, the best things come to those who wait.  Or so I’ve been told. 

 

Thanks for reading,

Julie S. Paschold

May 15, 2020

Rewritten December 31, 2022

Water and the Hydrologic Cycle

 

Water

 

When you see a picture of the earth, you see that a majority of it is blue.  Three-quarters of the surface of the earth, in fact, is covered in water.  That’s 118,500,000 square miles covered with the stuff. 

 

If there is so much of it on earth, why has the U.S. Environmental Protection Agency been freaking out for decades about water?  The government developed the Clean Water Act, and allowed states to establish and enforce regulations enforcing the quality of water.  Neighboring states argue about water rights, and who has the right to what amounts at what times.  Why all the fuss?

 

Well (ha!), of the estimated 327 million cubic miles of water, 97.22% of it is in the oceans—which means it is salt water, and not usable as is for growth; and 2.15% is fresh but frozen in glaciers and icebergs.  That leaves only 0.03% left to circulate through what we call the “hydrologic cycle” and on which every growing thing depends.  This fresh water cycles through snow and rain, rivers, lakes, ponds, underground, in the soil, and evaporated as water vapor in the air. 

 

Although we have 981,000 cubic miles of water in the whole hydrologic cycle at any one time on the entire earth, the water in the air as vapor or awaiting precipitation (say, 25% of the hydrologic cycle) isn’t immediately available for living things to utilize.  That leaves us water in rivers, lakes and ponds (surface water), and water in the soil and under the ground (groundwater). 

 

So, with the surface and groundwater, we have 735,750 cubic miles of fresh water for every single living thing here on the whole earth to utilize.  How much of this water that is available to us can we see?  For every lake or mile of river on the surface of the earth, there is a volume of water 25 times that underground.  This groundwater is stored in aquifers, or reservoirs of rocks containing pores and holes that the water flows through. 

 

Okay, so I’ve thrown a whole mess of numbers at you.  What’s the bottom line?  Of all the blue that you see on a photo of planet earth, a small drop of that is available for us to share with the plants and the birds and the bears and the bees.  That means we have to take care of what we have.  If chemicals or contaminants leak into one part of the hydrologic cycle, it can infiltrate the whole thing.  And although the earth does tend to heal itself, there is only so much it can do.  Certain chemical compounds don’t disappear.  We have to be responsible caretakers of this planet. 

 

So be kind—not only to each other, but to Mother Nature as well.  If you take care of her, she will keep on taking care of you. 

 

 

Julie S. Paschold

March 30, 2020

 

Reference: Soils in Our Environment: Seventh Edition by Raymond W. Miller & Roy L. Donahue. 1995. Prentice-Hall, Inc., Englewood Cliffs, NJ.