Indemnify demonstration on a Champion Bermudagrass green in South Florida. Photo: Bayer

Bob Lively faced steep challenges when he took the superintendent job at Greens and Grounds at Edgewood Valley Country Club in La Grange, Ill., in 2015. The 107-year-old golf course in Chicago’s western suburbs has push-up Poa annua/bentgrass greens.

“Our members want very firm, very fast greens,” says Lively, who earned a degree in turfgrass management from Rutgers University. “But I struggled to keep any type of root structure on a few of those greens. I practically lived on the course for the first two summers because I was afraid to walk away. I did everything I knew to grow deeper roots, but nothing seemed to work.”

Lively knew a few things about push-up greens, having worked with them for most of his 25-year career. He vertidrains monthly with solid 12-inch needle tines. He also slit-seeds heavily in spring and fall, while maintaining the same mowing height as the rest of the greens. At first, he supplemented with spoon feeding and hand-watering. He even cut trees to alleviate shade issues on one green. But he still couldn’t get roots on three of the greens.

After trying multiple cultural practices, Lively conferred with his distributor rep, who suggested he sample his greens for nematodes. The result? Tests on one of the greens sampled showed an average of 4,020 stunt nematodes per 100 cc of soil. Since this was above the damage threshold, he concluded plant parasitic nematodes were causing his problems. Chad Hauth, his Bayer Environmental Science field rep, recommended he try a new product, Indemnify® nematicide from Bayer.

“Even though we only tested three greens, we sprayed all of our greens with Indemnify just to be on the safe side,” Lively says. “We sprayed on June 12, 2017 and within days I saw a huge difference. They had always been a tannish color because I used a lot of growth regulators and kept them very lean so they’d be fast and firm. But suddenly all of my greens were truly green – and the only difference was Indemnify. It really kicked the crap out of those nematodes.”

How Indemnify Works

Indemnify offers both curative and preventative control of key nematodes, including ecto- and endo-parasitic nematodes like sting, stunt, root knot and ring. The product has a Caution signal word on the label and requires only standard personal protective equipment. Applicators need only water-in the material to the depth of roots within 24 hours after spray application. Built as a stand-alone nematicide, Indemnify contains a soil surfactant, so there is no need for additional adjuvants.

“Stunt nematodes are one of four we typically see in turfgrass in the Northeast — and they can do a lot of damage,” says Dr. Nathaniel Mitkowski, plant pathologist with the University of Rhode Island. “Stunt nematodes attack plant roots but the symptoms vary — you can get wilting, thinning or turf yellowing. They cause different symptoms at different levels.”

A demo sample of a Tifdwarf Bermudagrass green in North Florida. Photo: Bayer

Mitkowski began testing Indemnify last fall. “It’s the first material I’ve used in a very long time that’s shown such immediate and dramatic results,” he notes. “Superintendents often see a difference within two weeks. We’ve also been very impressed with the safety of Indemnify. The old product, Nemacur, worked fantastically well but was extremely toxic. It’s nice to have a material available that is relatively safe to the applicator and without the potential environmental damage.”

Putting the Sting on a Southern Problem

In the South, Dr. Bruce Martin agrees. “Indemnify has filled a huge niche from the standpoint of sting nematode control,” says Martin, plant pathologist with Clemson University’s Pee Dee Research and Education Center in Florence, S.C. “Sting nematode is a major pest on Southern golf turf. We did not have good materials for controlling this pest until Indemnify came along. I’ve tested it for several years and results have been phenomenal.”

Martin has found that fall applications of Indemnify work well in the Carolinas, Georgia and northern Florida on bermudagrass turf. “A preventive application in October or November works because Bermuda is going into dormancy in the transition zone,” he explains. “You want to protect the roots and optimize plant health prior to dormancy as much as possible. Indemnify can also be used in the spring to ensure normal green-up and transition of turfgrass. And the product can be used curatively at any time.”

A demonstration on an ultradwarf Bermudagrass green with sting nematodes. Photo: Bayer

Sting nematodes thrive on sandy soils, which are common in coastal areas, adds Derek Settle, Ph.D., technical service specialist with the Bayer Green Solutions Team. “But when you construct a golf green, you bring in sand and can easily introduce sting nematodes on plant parts or sod. Whether they are USGA-spec or push-up, most greens are vulnerable to nematodes. And no other nematode has such a low threshold level as sting nematode. It only takes about 20 - 40 per 100 cc of soil to cause damage.”

Misdiagnosing or Masking Symptoms

Nematodes are a nagging issue frequently either misdiagnosed or addressed by hand-watering at mid-day to alleviate wilt stress, says Settle. “In a way, excellent water management only masks nematode symptoms,” he says. “Until superintendents use a good nematicide, they don’t realize what’s causing their problems. Once they solve the issue, they can often send their hand-watering crew home at lunchtime.”

That is exactly what Lively did on his Illinois golf course. After spraying Indemnify, he not only stopped hand-watering greens every day, he began sleeping better at night. When he retested his greens in July, Poa roots had grown from 2 to 5 inches, while bentgrass roots were an astounding eight inches long. Tests revealed that stunt nematode counts went down from 4,020 to just over 1,000 — barely over the threshold.

“My greens have never been better — both species of grass reacted positively to Indemnify,” he notes. “I believe this is because all the nutrients in the soil became available to the turf after nematode levels went down. They were beating up on the roots and when they started dying off, the plants got better.”

He adds: “I can’t say enough about this product. It’s unlocked all the potential in my greens.”