Pest and disease control update
Turf pests and diseases are some of the most common, and frustrating, issues for sports field managers. University/extension turfgrass teams focus their research on issues that play a crucial role in turfgrass management. Their research plots provide comparative, scientific data that can be applied by turfgrass managers to their individual programs. It also can be used by the product manufacturers as comparison to their own research findings and to augment further product refinement and development. Sports field managers in turn provide their feedback on product results under actual field use conditions to further enrich useable data. Problems on the field often become the focus of research trials. It’s truly a team effort.
Pull turf samples to check soil conditions, root development and thatch levels.
PHOTO BY STEVE TRUSTY.V
Cover the basics
The expertise of turfgrass specialists, entomologists and pathologists is essential to turf mangers. It’s even more critical when unseasonal or rapidly changing weather conditions bring unusual insect and disease activity, as it did in many areas this past spring. Expertise in weed control is part of this big picture, but we’re not addressing weeds in this article.
Part of the support these specialists provide is tracking growing degree days (GDD). Daily maximum and minimum temperatures are used along with a base temperature to calculate a GDD value for each day. Combined, these measure the heat accumulation that can be used to predict plant and pest development rates.
With March weather three to four weeks ahead of schedule, Dr. Nick Christians, Iowa State University professor of horticulture, and other turf team personnel kept a running commentary with current GDD information and sightings from the field. It was all posted on the ISU Iowa Turf Blog: www.iaturf.blogspot.com.
With similar conditions, Dr. Lee Miller, turf pathologist with the University of Missouri in Columbia, kept turf managers updated on http://turfpath.missouri.edu/reports. He posted, “Due to the rapid ascendancy to a conducive environment of late spring/early summer diseases, various outbreaks that would normally be separated by months can be infecting turf now.”
He also emphasized what all these turf specialists consider the most important step in insect and disease control: properly identifying the problem.
Thus, researchers in all areas continually analyze insect and disease infestations to more precisely identify timing of the developmental stages of the attacking pests and types and effectiveness of control options, including mode of action, timing and application strategies. Research also helps determine what conditions make turfgrass susceptible to which pests, and what cultural changes can reduce that susceptibility.
Track what’s happening on your turf, recommends Dr. David Shetlar, (the BugDoc), professor of urban landscape entomology at The Ohio State University, OARDC & OSU Extension. He suggests downloading an image of the athletic facility from Google to map out the locations of insect activity. Pathologists also suggest mapping disease activity. Turfgrass areas most susceptible to attack are the first places to scout in your IPM program.
This University of Georgia field day exhibit shows insect life cycle stages; key information for accurate identification of pests.
PHOTOS COURTESY OF DR. CLINT WALTZ UNLESS OTHERWISE NOTED.
What’s up with disease control research?
Follow the research at The Ohio State University on www.buckeyeturf.blogspot.com. The article co-authored by OSU’s Pam Sherratt, sports turf specialist, and Dr. John Street, associate professor and turfgrass specialist, covering “Spring Diseases on Sports Fields,” appeared in the March 2012 issue of SportsField Management.
Dr. Grady Miller, professor of crop science for North Carolina State University (NCSU), reports spring dead spot is their major bermudagrass disease issue. He says, “A big factor is losing Rubigan, the now-withdrawn product previously used for its control on athletic fields.” To find an alternative, Dr. Lane Tredway, associate professor and extension specialist in turfgrass pathology, recommends checking the NCSU Turf Pathology site on Fungicide Performance Testing (www.turfpathology.org/Pages/fungicide_evaluation.aspx ) and filtering by spring dead spot and the specific products under consideration.
Tredway participates with other pathologists in supplying turf disease activity reports for their regions on the blog: www.turfdiseases.org. Other pathologist participants include: Dr. John Kaminski, Penn State; Dr. Megan Kennelly, Kansas State University; Dr. Jim Kerns, University of Wisconsin, Madison; and Dr. Frank Wong, University of California, Riverside.
An area of research for Miller is the efficacy of granular fungicide formulations as compared to liquid formulations of the same product, as well as other granular and liquid formulations. Data presented at the 2011 field day is available online. For updates on the sports field-specific research of Dr. Brad Fresenburg, check out http://turf.missouri.edu/stat.
Mary Owen, extension turf specialist, is part of the University of Massachusetts turf team. Research and observation updates are posted on UMass Turf Talk, with automatic email notification offered at: www.extension.umass.edu/turf/management-updates.
Dr. Geunhwa Jung, associate professor in the department of plant, soil and insect science, is focusing much of his research on fungicide resistance. Part of that includes working with volunteers who are testing a fungicide-resistance field kit. He says, “It’s a quick diagnostic tool that takes the principles of the dollar spot fungicide resistance assay to the field for on-site testing.”
Dr. Joseph M. Vargas, professor at Michigan State University, has been focusing his research on fungicide resistance, disease management, biological control and chemical control. He says, “My work on fungicide resistance points to use of one product until the degree of control wanes, then switching to a second product. My research shows alternating two products does not extend the effective control period.”
Side-by-side turf plots provide great opportunities for direct comparison.
His research also shows a dramatic reduction of leaf spot and necrotic ring spot on Kentucky bluegrass with adjusted cultural practices. Vargas says, “We’re using a combination of light daily irrigation, core aeration spring or fall, mowing height between 2 and 3 inches, and managed fertility, at least .5 to 1 pound of actual nitrogen once a month during the active growth season. We’re seeing enough control that no treatment applications are required.” To further explore his and other MSU research findings, go to www.plantpathology.msu.edu.
What’s up in insect control?
The influx of new technology in insecticides has greatly expanded the control options. “These new insecticides have extended residual action, different application timing strategies, and fewer nontarget effects,” states Shetlar.
Part of Kai Umeda’s extension outreach for the University of Arizona includes an annual spring turf seminar for sports field managers that includes updates from the Karsten Turfgrass Research Facility. For the latest data check out http://turf.arizona.edu.
Umeda says, “My original research here included monitoring and surveying the grub population with blacklight traps to more accurately time control product applications. Now we’re seeing billbug activity that probably involves four different species, so that’s another research target.”
Dr. Pat Vittum, UMass professor of entomology, keeps bug activity reports up to date on Turf Talk. She says, “Invasive crane flies are a concern on sports fields, and we are definitely seeing two species. Larval damage is similar to that of white grubs, including the additional impact of skunks and raccoons tearing up the turf digging for them. We have great data on the European crane fly, but the common crane fly is making its way into the Northeast and we have no field trials on it. We’ll be looking at it this year.”
Shetlar says, “For insect control, there are several issues overriding what’s effective. With budget limitations, cost is an issue. In some municipal areas it is very clearly stated that only the least toxic materials can be used, with none to be applied without official approval. While some don’t like anything that’s synthetic, the new class of insecticides, anthranilic diamides (chlorantraniliprole) insecticide category 4, is nearly nontoxic; less toxic than many ‘natural’ type products. It only affects how calcium works in the muscle tissues of insects and other arthropods, including centipedes and white grubs.” The first product introduced in this category was Acelepryn from DuPont.
“The true, bio-based organics take a different mindset in terms of what to expect,” says Shetlar. “Yet they fit a segment of the market; different needs for different people.”
Dr. Frank S. Rossi, associate professor in the horticulture department at Cornell University, is best known as “the Turf Guy.” His research and extension outreach emphasize increased resource efficiency and improved environmental compatibility, the sustainability factor. To tap into his communications, go to www.hort.cornell.edu/turf.
Rossi says, “Here in New York state, the recent passing of the Child Safe Playing Field Law bans the use of all chemical pesticides on playgrounds and fields. There is great interest in exploring alternatives to meet the needs of sports turf managers.”
Insect control is part of that equation. He says, “Research is underway here at Cornell and other universities on improving the effectiveness of nematode applications for grub control.” Fresh stock of the best strain for the target pest, timed and applied correctly to maximize their activity is essential.
Shetlar also points to another option, Bacillus thuringiensis (Bt), deemed a “microbial insecticide.” He says, “We had a strain back in the early ’90s that produced good results against white grubs, but couldn’t compete with the new insecticide introductions.” With research on another strain underway, he anticipates a major market entry in the future.
Organic insecticides include CedarCure, introduced by ICT Organics in 2011, and Topia, introduced by FMC Professional Solutions in 2010.
On the disease control side, Companion Liquid Biological Fungicide was introduced for turfgrass and landscape use in California in February of 2011 by Growth Products. ICT Organics introduced 1-2-3 NPP (Natural Plant Protection) in 2008. It’s an organic disease control classified as a minimum-risk pesticide (FIFRA 25 (b) exemption) and labeled for most major turfgrass diseases.
Dr. Clint Waltz, associate professor and turfgrass extension specialist, is part of the University of Georgia turf team. He says, “One of our grad students is researching the use of compost for organic mitigation of dollar spot. He’ll be doing his thesis on it later this year.”
Rossi says, “While product development continues, we have begun to investigate overseeding and regrassing options with turf species more likely to tolerate pest pressure such as tall fescues under lower maintenance and still provide the traffic tolerance.”
Shetlar is working with Ohio sports field managers on slit seeding of turf-type tall fescues into their Kentucky bluegrass practice fields to incorporate enough “stems with the endophyte” to reduce insect activity. He says, “That’s normally about 1 to 2 pounds per 1,000 square feet. Most of the perennial ryegrasses have the endophyte, too. Work with a turf seed specialist to identify varieties with good endophyte levels that will match the color and texture of the existing turf.”
Rossi says, “Questions remain regarding the role of pesticides in sustaining healthy and safe sports turf. Some might argue chemical pesticides have kept us complacent about maximizing cultural options. Others would say that when used properly they are an important tool. In the end, the sports turf manager’s expertise is the linchpin that your success revolves around. Your ability to access the latest research and properly integrate it into your operation is the key.”
The most important goal of all this research is to provide science-based data so the user is able to select the most efficacious product for the pest, timed and applied correctly.
The author is a contributing editor for SportsField Management.