Target Nematodes

Zone-specific application puts the nematicide where it’s needed

By Amanda Huber


At a time when saving every penny on inputs is critical, knowing you are only putting product out where it is needed, and not where it is not, is like money in the bank.

When your whole system is integrated to the point where the planter will precisely place the seed exactly where the nematicide is; and the nematicide is necessary because you know just how many nematodes there are per cubic centimeter; and at harvest, the peanut plant will be dug on the exact coordinates of where the seed was placed, then you are using precision agriculture to its full potential.

That’s what Craig Bishop has for 2008. Bishop grows peanuts, cotton and corn in between Marianna and Altha, Fla. Like many growers, he deals with root-knot nematodes in peanut and reniform nematodes in cotton. But instead of applying Telone broadcast, Bishop – with the help of Dr. Jim Rich, University of Florida Extension nematologist, and Debbie Waters, Innovative Crop Technology in Tifton, Ga. – is targeting nematodes with zone-specific applications.

Bishop’s start with precision-agriculture technology first came with variable-rate fertilizer application and then with autosteer technology.

Autosteer Pays For Itself Fast
“We’ve been doing variable rate for about seven years, and we’re extremely pleased,” says Bishop, who grows 1,200 acres of peanuts, 2,500 acres of cotton and 200 acres of corn, plus wheat. “The soil fertility has really leveled out.”

Bishop says other fields he has rented that have only had a set amount of fertilizer broadcast over the whole acreage may need anywhere from no fertilizer applied to a lot.

“The fertility will vary just that much over the whole field where it has had too much in some places and not enough in others,” he says. “That will affect the crop’s yield.”

Bishop says he has had the autosteer for three or four years now. “We are running the Trimble Autosteer System.”

Bishop says they use the autosteer for everything from planting to harvest and from variable-rate fertilization to zone-specific application.

“We use it all the time. It really helps in digging peanuts. It is one piece of equipment that pays for itself the fastest,” he says.

Bishop has also invested in a yield monitor, the data from which is used to create management zones.

Zone Vs. Grid
To create the management zones, Bishop sends the yield data to Waters just after harvest.

“Craig sends me the yield data, and I normalize the yields and create the zone maps for him,” Waters says.

Then, using the zone maps, Bishop pulls soil samples from each zone, and this year he also pulled the nematode samples in the zones.

Bishop says there may be anywhere from two to five acres in a zone.

“We used to do grid sampling, but zone sampling follows the soil much better. You can literally see when the soil changes,” he says. “When you are riding across the field taking samples, you will start to detect those real subtle changes in the soil from one zone to the next.”

The nematode samples Bishop pulled were sent to Rich for analysis.

“Craig took zone samples on nematodes, and we ran them and made a count of the nematodes. I gave it back to him, and then, using the nematode numbers in each zone, Waters created an application map,” he says, adding that determining where the cutoff point is for treatment is as much an art as it is science.

“He [Rich] tells me how many are in each zone, and at what point I need to treat. The information is communicated to Waters who makes a nematode-prescription map.”

Tying It All Together
Bishop says it is Waters that links all the data together.

“She ties my information to Jim Rich’s information,” he says. “You can really tell that she cares about you and what she is trying to help you do.”

“I send him a Telone-application map that he can load into the computer in the tractor,” says Waters, who calls Bishop a very innovative grower.

Bishop says he downloads the application map onto a flashcard.

“I put it in the tractor, turn it on and the tractor practically runs itself,” he says. “Instead of broadcasting Telone across all the acres, we are applying it only where nematodes would be a problem. In a 70-acre field, there may not be but about 13 or 14 acres that need treating.”

Bishop puts out Telone two, three or even four weeks before planting.

“We run it down the back of our shanks on our ripper/bedder and rip it under the soil,” Bishop says. “The autosteer puts the seed right dead on top of where you ripped.”

For producers who do not have autosteer, Rich says broadcast applications of Telone are recommended.

“It was determined in extensive research years ago that Telone under peanuts is a good management practice,” he says. “If a producer has a mapping system and steering capabilities for in-row application of Telone, they can be sure they are planting where they applied Telone.”

Anticipating The Yield Data
Although he has the whole season ahead of him, Bishop says he is anticipating the yield data from this year’s crop.

“I am looking forward to seeing whether the zones move and if the fertility of the zones has changed,” he says.

For her experience, Waters says that zones do change over time.

“In places where we have been doing zones the longest, which is about five years, the zones are getting larger over time,” she says. “Zone management started with fertility. But now that fertility is leveling off, the yield differences must be due to something else.”

Thus the reason to look for nematodes by zone.

Rich says many growers may not want to take soil samples, and also nematode samples, because having samples analyzed has gotten so expensive.

“We hope that when we learn more about zone management of nematodes, in time, we can depend more on the yield monitors and less on sampling,” he says.

Next year, Rich says they will take electrical-conductivity readings for each zone, which can also be used to detect differences in soil type. Soil type is a critical factor in nematode management.

“You might have the same nematode in two different soil types, and one needs treating and one does not,” says Rich, who hopes their efforts narrow down the efficiency even further.

For now, with the nematodes counted, maps made and Telone applied, Rich and Waters can only wait and hope that Bishop has favorable weather, few disease or insect problems and a good harvest.