New Insecticide Labels to Increase Focus on Pollinator Protection

As part of an ongoing effort to raise consciousness about the potential threat to pollinators posed by neonicotinoid insecticides, the USEPA recently unveiled new pesticide labeling criteria. The new labels will contain a bee advisory box and icon with information on routes of exposure and spray drift precautions. 

The recent announcement focuses on products containing the neonicotinoids imidacloprid, dinotefuran, clothianidin and thiamethoxam. The EPA will be working with pesticide manufacturers to change labels so they are in compliance the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) safety standards.

In May, the U.S. Department of Agriculture (USDA) and EPA released a comprehensive scientific report on honey bee health, showing scientific consensus that there are a complex set of stressors associated with honey bee declines, including loss of habitat, parasites and disease, genetics, poor nutrition and pesticide exposure

Although there is no data presently connecting the use of these insecticides in turf to declining bee health, it may prudent for pesticide applicators to become reacquainted with product labels to ensure they are being used in a safe and responsible way. Current labels already include a hazard statement concerning the risk to pollinators posed by these insecticides.

The EPA also recently released new enforcement guidance to federal, state and tribal enforcement officials to enhance investigations of beekill incidents. When it comes to pesticides use, those of us in the turf industry really do need to be doing everything we can to avoid unnecessary risks.

Doug Richmond
Turfgrass Entomologist
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Weed of the Month for August 2013 is Common Bermudagrass

Common Bermudagrass  

Biology: Common bermudagrass (Cynodon dactylon) is the most commonly used turfgrass in the southern United States, but it is also a difficult-to-control weed in northern turf. Bermudagrass is a drought tolerant, warm-season, perennial grass species that tolerates low mowing and actively spreads vegetatively by both rhizomes and stolons but also has the ability to spread by seed.

Identification: Bermudagrass has a blue-green leaf and forms large patches in lawns as it spreads radially from rhizomes and stolons once it becomes established. The stolons can be easily spotted spreading over sidewalks and drives.

Stolons of bermudagrass are visible creeping over a street curb.
Bermudagrass rhizomes are thick and can be found in the soil.

The patches are easily noticed in the summer months when cool-season turf is stressed by heat or drought. Patches are also noticeable in the early morning as bermudagrass holds a heavy dew on its leaves in the early am. In the winter months, bermudagrass is apparent as brown, dormant areas of turf.

Green bermudagrass is apparent in this drought stressed cool-season turf.

Green bermudagrass is apparent in this drought stressed cool-season turf.

Heavy dew on a small bermudagrass patch.

Green cool-season turf surrounding a dormant bermudagrass patch.

Leaves can be very hairy or sparsely hairy depending on the biotype but the ligule will always have hairs.  

The finger-shaped spikelets on the bermudagrass seedhead are similar to a crabgrass. Bermudagrass will produce seedheads from mid-summer until fall. Spikelets typically have 3-6 spikes in number.

Cultural control: Enhance cool-season turf density through overseeding and fall fertilization.

Biological control: None known.

Chemical control: Bermudagrass is the most difficult to control turf weed. Keep this in mind when trying to control it! These “control” methods should be regarded as ways to “suppress” bermudagrass. It is extremely difficult to “eradicate” bermudagrass. Different situations require different approaches. The areas below describe bermudagrass control in different situations for different users:
  • Control before seeding or sodding an area during renovation
  • Control for homeowners 
  • Control for professionals

Control before seeding or sodding an area during renovation
The most effective way to control bermudagrass is with a preplant soil fumigant. For most, fumigation is not an option because it is so costly and because of specialized application equipment needed. A good alternative is to make three applications of glyphosate over the growing season (May, July, and September). Wait three to four weeks for regrowth before making the follow-up applications. Research shows that a tank-mix of 3 qts/A glyphosate plus fluazifop will improve bermudagrass control over glyphosate alone. When using fluazifop, be aware that it will have some residual soil activity. Wait at least 30 days before seeding turfgrass after applying fluazifop to bare ground or 14 days after an application to turf.
  • Professional products that contain fluazifop only that can be used during renovation include Fusilade II and Ornamec. 
  • Homeowner products that contain fluazifop only that can be used during renovation include ORTHO GRASS B GON GARDEN GRASS KILLER 
Control for homeowners 
There are few “over-the-counter” products available for bermudagrass control. One such product is Bayer Advanced Bermudagrass Control for Lawns. Multiple (3 or more) applications will be needed to suppress bermudagrass. I suggest that homeowners make applications at the start of the end of the summer when the bermudagrass is not actively growing. Summer applications are generally less effective on bermudagrass and could injure their lawn when applied to drought stressed turf or heat stressed turf as temperatures approach 90 degrees. I suggest using this product twice in the month of May, twice in September, and once in early October. Treating during the cooler periods of the year while the weed is green will help to control the weed while reducing the risk of injuring your desirable lawn grasses. Having said all of this, remember that this is the toughest turf weed to control and few options are effective. At best, the homeowner will be able to suppress/reduce this weed but likely ever completely eradicate it.

Control for professionals 
There are many situations on golf courses or lawns where bermudagrass invades. There are also many cool and warm-season grasses that bermudagrass invades. Each situation in each different turf spcies requires a different approach. Consult Turfgrass Weed Control for Professionals Publication (AY-336) for more information on professional options for control in these situations.

For more information on weed control, search this blog and archived turf tip postings and check out our Turfgrass Weed Control for Professionals Publication.

Aaron Patton, Turfgrass Extension Specialist

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2013 Imprelis Update: Tree Maintenance, Replacement, and Disposal

This article provides a 2013 update of this issue and what we hope will be the last and final update on Imprelis. This update addresses some of the frequently asked questions about Imprelis® in 2013.

2013 Imprelis® Update: Tree Maintenance, Replacement, and Disposal (PDF) (08/13)

For a complete review of the facts and a more detailed description of the problem, see “A Turf Professionals Guide to Suspected Imprelis® Herbicide Injury in the Landscape” and “Imprelis Update: 2012 Field Notes on Injury and Recovery” available at our Imprelis Clearinghouse Website.

Aaron Patton, Turfgrass Extension Specialist, Purdue University

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New Publication: Calibrating Ride-on Sprayers and Spreaders

The use of ride-on sprayer/spreaders by lawn care operators (LCOs) and the sports turf industry has increased dramatically since they were introduced in the 1980s. Ride-on equipment offers a number of competitive advantages over walk-behind spreaders and the hand-gun/hose-reel type of application. This publication addresses specific procedures for separately calibrating the pesticide sprayer and the fertilizer spreader of ride-on equipment. The goal is to ensure proper application accuracy to optimize performance.

Calibrating Ride-on Pesticide Sprayers and Fertilizer Spreaders: Keys to Application Accuracy (PPP-104)

Aaron Patton, Turfgrass Extension Specialist, Purdue University
Fred Whitford, Coordinator, Purdue Pesticide Programs

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Rust Disease – 2013

The 2013 rust disease outbreak seems to have arrived a little earlier than usual.  My thoughts about the current rust epidemic are intended for lawn care professionals, who must address reasonable questions from their clients.  Most professionals are very familiar with the basics of rust disease.  To briefly review from the 2013 perspective--the ample precipitation favors dispersal of rust spores and subsequent infection of susceptible turf.  The disease is largely cosmetic, but the orange spores that are easily dislodged from leaf surfaces can be more than a nuisance, covering shoes, pets, and lawn mowers with a rusty residue.  New spring-seeded lawns that lose vigor during heat and drought conditions of summer may be severely damaged by rust.

One question about rust is asked more than any other—Will it harm my dog?  The answer is no…and no further explanation is necessary.

Another question frequently asked is – If I collect my clippings after mowing, will the disease disappear?  The answer here is “no” also.  There are tens of millions of rust spores in the air--inoculating your lawn every day.  Also, because the rust pathogen must complete every stage of its life cycle on a LIVING host, spores on your clipped grass blades will soon die, and no longer be a threat to the yard.

A final question regards control—both long and short term. 

If the lawn is in need of any kind of renovation, now is the time to consider Kentucky bluegrass cultivars with rust resistance.  Many of the newest cultivars are only slightly affected by the rust pathogen.  Local lawn care professionals or garden stores will have access to information about rust-resistant grass.

Keeping the grass healthy with water, fertilizer, and regular mowing normally will keep rust at bay.  This year seems to be a little different, maybe because of all the rain, and the fact that nutrition is a little low at this time of year.  Suggest trying the fertilizer route first.  Applying the equivalent of 0.2 lb N per acre may do the trick.  Be prepared to resume mowing if the rain continues, and do not apply if the 3-4 day forecast includes daily high temperatures in the 90’s.

The final approach is chemical.  There are excellent fungicides available that will shut down a rust outbreak in less than a week.  The DMI and QoI  (strobilurin) fungicides are very effective against rust but, on well-established turf, should be considered only as a remedial treatment.  On newly seeded stands, fungicides should be applied at the first sign of disease.  In most cases, outbreaks will be quelled with a single application of an effective fungicide combined with efforts to encourage turf growth.

For more about rust disease, access the Purdue Turf Program website and click on “publications”.  In that list, you will find BP-110W  “Rust Disease”. 

Dr. Rick Latin, Professor of Plant Pathology

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