What is in this article?:
• Thomas, Jarrell developed a soil map for most of the 1,500 acre farming operation he operates with his father B.L. Jarrell.
• The map shows fields categorized as low, medium and high risk for developing damaging nematode populations.
• Using a simple off-on system developed by Clemson University researchers, he uses a simple variable rate application method to apply higher rates of nematicides in fields with higher risks of nematodes and applies less or none to fields with low risk of nematode damage.
“We see nematode numbers go down to nearly nothing after we plant a field in peanuts. However, neither one year of peanuts, Temik or Telone has noticeably reduced the number of nematodes over a long period of time.
“Nematode samples come back at zero or near zero right after peanuts, but by the time we plant another crop, populations build back up,” he says.
Their typical rotation is two or three years of cotton and one year of peanuts. The second and third years of cotton are especially susceptible to high nematode populations.
“In 2007, we started doing some Veris work with James Thomas. We started out using varying rates of potash and lime based on the soil maps generated by the Veris machine,” he adds
Clemson University Plant Pathologist John Mueller helped develop some of the nematode management strategies used by Thomas to help the Jarrells manage nematodes in their cotton.
Mueller says, “In our most recent tests, using variable rate application, we varied from zero Telone II to four gallons per acre in the same field. Without variable rate technology, the grower would typically treat for the highest nematode populations using the higher rate of nematicide across the entire field.
“As the nematode pressure goes up in a cotton field and the cost of pesticides goes up, the need for more precise application becomes increasingly cost effective, Mueller says.
“In one field with variable soils and subsequently variable nematode pressure, we increased yield by 55 pounds of lint per acre. But, we only averaged one half gallon of Telone II per acre, versus the standard uniform treatment of three gallons per acre. So, we saved $25 per acre on Telone II costs plus another $25 or so on increased lint yield.
“It is affordable technology that can put money in a grower’s pocket,” Mueller concludes.
Veris measures the electric conductivity of the soil. In heavier soils, there is more conductivity and less in sandy soils. Jarrell says they had the Veris maps and Thomas encouraged them to use the maps to develop a simple variable rate strategy for nematode management.
“James started doing nematode sampling for us and it was a logical decision to use the Veris maps and soil sampling to determine where high levels of nematodes were most likely to occur. That’s when we started using Telone on fields with the highest risk of nematode damage.
“We are very concerned about the loss of Temik. While Temik wouldn’t take care of nematodes in some of our fields — the ones with high risk ratings — it did a good job on medium and low level risk fields.
“Now, with no Temik, we feel like we don’t have a choice other than increasing our use of Telone on these cotton fields at medium risk,” Jarrett says.