Solving the Nematode Puzzle
From Cotton Grower Magazine – August/September 2015
Kenny Ray Davis is a do-it-himselfer when it comes to what’s grown and what’s used on his family farm. Davis’ 2,100-acre farming operation sits in the middle of prime farmland near Fitzgerald, GA, with seven different types of soil – ranging from clay to sand to loam – intermingled throughout his fields.
The one constant among that mix of dirt is nematodes.
“I think of a nematode like a pigweed,” said Davis. “If you don’t think you have them, then you probably do. And the longer you put off some type of treatment, the higher those nematode numbers are going to go.”
Davis, working closely with his consultant Brandon Phillips of Phillips Ag Service, has implemented a systematic – and aggressive – program to manage nematodes across his fields without seriously impacting his bottom line.
“We talk about the height of cotton and variations that nematodes can cause in fields and soils,” stated Davis. “What we’ve seen is we’re leveling the playing field in a lot of ways. And, it all started with the decision to add Telone under our fields.”
“When you get into 60 cent cotton, the 300 to 500 pound per acre boost we get from Telone is a game changer,” added Phillips.
More Tools to Work With
A University of Georgia survey conducted several years ago showed that 72 percent of the state’s fields were infested with root knot nematodes – not including other acres hiding reniform, sting and lance nematodes. Growers in the state have been fighting the yield-sucking pests for years. Yet the prospect for managing or minimizing their impact has never been brighter.
“The tools that we have now – nematode resistant cotton varieties from three different companies, a new nematicide to complement seed treatments, and Telone – are really what we’ve been waiting for,” said Bob Kemerait, University of Georgia Extension pathologist. “We can’t grow cotton on a statewide basis without some way of managing nematodes. I think a measure of the success we’re starting to see is that acreage of nematode resistant varieties have doubled this year from last year.”
Kemerait points out that no other product or variety matches the effectiveness of Telone. But he’s also encouraged by what he’s seen this season from Velum Total. The product is applied in-furrow, and growers appear to be willing to try it, especially those who also grow peanuts and are more familiar with furrow application.
“It’s going to be more protective than a seed treatment will be,” he said.
He’s also been impressed with the evolution of the nematode resistant varieties, especially those that include dual gene technologies for insect and weed management.
“It may not be the variety that growers want to plant in every field,” he noted. “But where they have a problem, they certainly want to plant them. The thing I tell growers is when you plant a variety like this, you’re not only protecting your crop from nematodes this year, but it also helps you for next year, because the nematode population will be much lower than it normally would have been.”
Testing Drives Decisions
Davis and Phillips plan each input and decision carefully. A big part of that process involves extensive use of test plots to compare treatment options and varieties, both under irrigation and in dryland situations.
“We do these plots for ourselves,” said Davis. “I know we can learn from others, but I need to see it myself. We want to make sure something will work on our farm.”
Each fall, Phillips pulls nematode samples in areas where problems were detected during the growing season, then uses a Varis rig to map the soil type.
“After mapping, we usually apply Telone where it’s needed in the fields, typically the sandier-type soils,” he explained. “That’s generally about 60 to 75 percent of the fields. That’s a cost savings for 25 to 40 percent of the acres, while helping to increase overall yields. The minimum bump in yield that we’ve seen so far has been 200 pounds per acre.”
Phillips then pulls samples from the non-treated acres the following year to see if they’re missing something that’s not visually evident. “You can generally see in the fields where we put the Telone and where we didn’t,” he noted.
This year, their test plots involve replicated trials of nematode resistant varieties from Deltapine, Stoneville and PhytoGen. The plots have DP 1558NR B2RF planted beside DP 1454NR B2RF, ST 4946GLB2, PHY 427 WRF and several experimental varieties. Davis and Phillips are also comparing Telone to Velum Total and imidicloprid and Abound in-furrow versus seed treatments.
“We’d also like to see if we can get 1,200 to 1,400 pounds per acre with varieties like DP 1454NR B2RF on low-to-moderate count dryland fields,” said Phillips.
Jesse Story, an Ashburn, GA-based consultant, is also using plot work to help determine if the varieties alone could pay off for growers with less nematode pressure.
“We want to see how the different varieties can endure and tolerate nematode pressure to see if we can get to a point where they can save some money on nematicides,” he said. “I believe the aggressiveness of these varieties are helping us overcome some of the obstacles. A few years ago, we had to sacrifice some yield and quality if we planted into nematode pressure. That’s not the case anymore.”
Lowering Costs, Increasing Yields
Davis and Phillips used the imidicloprid/Abound treatment this year to help shave costs on seed treatments. The results have been positive.
“As far as expenses, we have less money per acre in our cotton crop,” said Davis. “And I have no doubt – barring some disaster before harvest – that we’ll exceed last year’s yields.”
Phillips is also positive about the outlook. “The last time we had cotton in these fields, it made 1,800 pounds. To me, this cotton looks better than that.”
He also adds a slightly different view of the challenge.
“A lot of growers in Georgia think stink bugs are our number one pest,” he stated. “But I think the nematode is. It’s robbed more yield than any other pest besides a plant bug in the Mississippi Delta. Those growers are spending roughly $200 an acre to control plant bugs, and we’re losing about $200 an acre to nematodes.
“Our question is, why wouldn’t a grower be using nematode resistant varieties and Telone or Velum Total?”
Sampling Is the Key Step
Kemerait doesn’t mind sounding like a broken record. But nematode sampling in the fall following harvest is just that important.
“Sampling gives growers a strong idea of what they can expect the following season,” he said. “They need to know what they’re going back into, regardless of what they’re going to plant. We know cotton prices aren’t where we want them to be. But it just makes economic sense to spend a little money on sampling now to help make the right management decisions for the coming season.
“It all starts with knowing what type of nematode is in their field and what those populations are. From there – between the consultant and Extension staffs all working together – we can help a grower make the right decisions.”