Still time left to sign up for Indiana Green Expo to be held Jan 11-13!

The registration deadline is fast-approaching for the Indiana Green Expo and forms must be postmarked by Dec. 31, 2011. The Indiana Green Expo is the largest turf, ornamental, nursery, and landscape conference in Indiana and is jointly sponsored by the Midwest Regional Turf Foundation and Indiana Nursery and Landscape Association. Over sixty experts from across the country are giving over 100 talks on all aspects of the green industry and a tradeshow packed into two days provides an efficient and cost-effective opportunity for educating your whole staff, regardless of what area of the Green Industry where you work. Plus there are huge discounts for bringing more than two employees. Indiana, Michigan, Ohio and Kentucky CCH’s, GCSAA education credits, and IAH certification units are all available. Full information as well as on-line registration is available at

Contact Jennifer Biehl with any questions.
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Winter Annual Weeds

Four types of broadleaf weeds exist: 1) perennial (those living more than two years), biennial (those living two years), 3) summer annuals (those germinating in the spring and dying in the fall), and 4) winter annuals (those germinating in the fall and surviving the winter and dying the following spring). Since many of these winter annual weeds are now germinated, I thought it might be a useful exercise to review their identification. Below is one picture of various winter annual broadleaf weeds. Be on the lookout for these this fall and next spring.

Annual bluegrass

Catchweed bedstraw

Common chickweed

Corn Speedwell


Prickly lettuce

Purple deadnettle

Sheperd’s purse

Aaron Patton, Turfgrass Extension Specialist

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Imprelis Return and Refund Program

On October 17, DuPont began a process to recall and refund Imprelis from Turf professionals. DuPont has contacted distributors, who will be coordinating with turf professionals to ensure that all remaining full and partially full bottles of Imprelis® are returned. Turf professionals have 10 business days to return all Imprelis® product (4.5 fl. oz., 1.0 gallon, and 2.5 gallon bottles) to them after the initial contact from the distributor. After returning the remaining Imprelis® to the distributor, turf professionals will be given either a refund or credits, depending on the distributor’s policy. In this EPA approved disposition plan, the EPA suggests that you maintain records associated with Imprelis®, including but not limited to: 1) quantities used and returned, including product lot numbers 2) application records, and 3) purchase records.

Below are links to documents useful to turf professionals who applied Imprelis® last fall or this spring. More information is available at and at (866) 796-4783.

Information From DuPont:

Imprelis Status Mailer to Users & Dealers (September 20, 2011)

DuPont Imprelis return & refund letter to applicators (October 17, 2011)

DuPont Imprelis return & refund letter to distributors (October 17, 2011)

DuPont Imprelis instructions for return & refund (October 17, 2011)

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Grass Clippings and Herbicides

I have received a few questions recently regarding the use of grass clippings on lawns treated with herbicides. Here is one of those questions: “Our Master Gardener Association will be working on a project in which they hope to use a great amount of lawn clippings to put down as compost in a large area. This will require lawn clippings donated from several different sites. Will they run into a problem with clippings from lawns that have been treated with Imprelis® this year? Would there be chemical residue which remains in the clippings and/or compost which should be avoided?”

The answer to that specific question is that we do not recommend that clippings from lawns treated with Imprelis® (aminocyclopyrachlor) be used in the composting. Even if Imprelis® was applied 6 months ago (applied in April, today’s date October 12) there still could be some Imprelis® residue present in the clippings or the soil. Although any herbicide residue may be minimal from a spring application, we 1) don’t fully understand how long Imprelis® lasts in the soil or the grass clippings and 2) Imprelis® is active at very low rates and thus even if just a little is left it could be enough to cause injury on a susceptible ornamental plant such as tomatoes in the garden or flowers in the landscape.

The Imprelis label states “Do not use grass clippings from treated areas for mulching or compost, or allow for collection to composting facilities. Grass clippings must either be left on the treated area, or, if allowed by local yard waste regulations, disposed of in the trash. Applicators must give verbal or written notice to property owner/property manager/residents to not use grass clippings from treated turf for mulch or compost.”

The Imprelis® label does not state how long not to remove clippings. Eternity, 1 year, 2 months? It simply does not say. Therefore, I recommend not to use clippings from Imprelis® treated lawns in compost.

What about other herbicides? Other herbicides applied to residential turf may have label language as well that restricts clippings from being collected. The Dimension® 2EW (dithiopyr) label also states “Do not use clippings from treated turf for mulching around vegetables or fruit trees.” Like the Imprelis® label, the Dimension® 2EW label also does not specify how long to wait after treating before clippings can be safely harvested. Another herbicide, Drive® XLR8 (quinclorac), states that “Clippings from the first three mowings after application should be left on the treated area”. This label makes it a little clearer when it is safe to harvest clippings. Most labels contain no reference whatsoever to “clippings”.

Therefore, language varies from label to label regarding the use of clippings for mulch or compost following a herbicide application. In most cases I would recommend not using clippings from a lawn treated with herbicide within one-month (approximately 3 mowings) unless the label states otherwise such as with Imprelis®.

Aaron Patton, Turfgrass Extension Specialist

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Imprelis Update: DuPont Begins Claims Resolution Process

On September 6, DuPont began a process to fairly resolve claims for impact on trees that DuPont™ Imprelis® herbicide may have caused. Below are links to documents useful to turf professionals who applied Imprelis® last fall or this spring. More information is available at and at (866) 796-4783. The deadline for submission of claims is November 30, 2011.

Note on fall fertilization: Fertilizing affected trees and shrubs during 2011 is not recommended, but fertilization of the turf in the fall of 2011 is recommended per normal turf fertilizer recommendations (see recent turf tips on September 1, 2011). When damaged trees and shrubs are surrounded by turf, take care to fertilize outside the drip line of damaged trees so not to stimulate new growth of the trees.

Information From DuPont:

Letter to Lawn Care Professionals from DuPont

Claims Resolution Process Lawn Care Professional Overview

Letter to Golf Course Superintendents from DuPont

Photography Instructions Before Removing Trees

Frequently Asked Questions about the Claims Process

Updated Documents from Purdue University for Use by Turf Professionals

A Homeowner’s Guide to Imprelis® Herbicide Injury in the Landscape

A Turf Professional’s Guide to Imprelis® Herbicide Injury in the Landscape

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Purdue Turf Scientists and Their Work Highlighted in Recent Press Releases

Scientists make turfgrass safer for animals, deadly for insects

September 6, 2011

WEST LAFAYETTE, Ind. - The right combination of compounds produced by a beneficial fungus could lead to grasses that require fewer pesticides and are safer for wildlife and grazing animals, according to Purdue University scientists. Read More

Purdue 'tool box' could be ace in the hole for golf courses

August 23, 2011

WEST LAFAYETTE, Ind. - Below par looks great on the leaderboard but never when it describes the appearance and playability of golf course putting greens. Purdue University researchers are working to help course managers produce winning greens at lower cost and with less labor. Read more.

Avoid use of herbicide Imprelis, Purdue experts advise

July 22, 2011

WEST LAFAYETTE, Ind. – Lawn care providers should not use the herbicide Imprelis on residential and other properties such as golf courses as experts try to determine whether it is injuring trees and ornamental plants and can be used safely, a team of Purdue University specialists advises. Read more.

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Making Adjustments to Your Fertilizer Program

Although the Purdue University Turf Program publishes information about how to fertilize your turf with nitrogen (N)-based fertilizers including standard rates and timings, there are many factors that influence these rates and timings. It is important that each turf area be fertilized according to its needs. For example, some areas require more nitrogen fertilization because they are highly trafficked and need additional nitrogen fertilization to promote growth and recovery. In another example, some older, well-established lawns may need less nitrogen fertilization because they have more organic matter in the soil (a natural source of some N fertilization). See the table below for more of these examples and make sure to customize your fertilization program to fits your turf needs.

Dr. Aaron Patton, Turfgrass Extension Specialist
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Fall Fertilization

Cool-season turfgrass species should be fertilized mainly in the autumn. September and November are the two best times to fertilize a lawn in Indiana. Fall nitrogen promotes good root development, enhances storage of energy reserves, and extends color retention in cool-season lawns. Most of the benefits from late fall nitrogen will be seen next spring and summer with earlier green-up, improved turf density, and improved tolerance to spring diseases such as red thread and pink patch, and reduced weeds.

There are many fertilizer choices available to the homeowner. Organic, inorganic, and synthetic organic products are all available. As with all plants, turfgrasses cannot tell the difference between the sources of nutrients. Some products contain high amounts of slow-release N while others contain none. Although there are exceptions to the rule, it is good practice to use products with a greater percentage of slow-release nitrogen sources during spring and summer months and a greater percentage of quick-release nitrogen sources in the fall.

For the September application, pick a product that contains some quick and slow-release nitrogen. The timing of the September application is anytime of the month after the daytime high temperatures are no longer in the 90s °F. The target application rate for this fertilization should be 1.0 lbs. N/1000 square feet.

The late-fall or November application timing should be near or after the last mowing of the year, but while lawn is still green. Typically, there may be a month or more between your last mowing and the time the grass turns brown or goes under snow cover. Generally the first few weeks of November are when to apply. Earlier Purdue research suggests that the nitrogen must be taken-up by the plant before winter to be most effective. Therefore, a quick-release (or soluble nitrogen source) such as urea, ammonium nitrate, calcium nitrate, or ammonium sulfate is most effective. The target application rate for this November fertilization should be 0.5 to 1.0 lbs. N/1000 square feet.

More fertilizer program information is available in AY-22: Fertilizing Home lawns at

If you are confused on how much of a particular product to apply to achieve a particular N-rate, use our fertilizer calculator to help determine exactly how much product to use:

Aaron Patton, Turfgrass Extension Specialist
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Staying Dry

Many in central Indiana are coping again with drought a second year (See drought monitor images for Indiana (current and fall of 2010). While many pockets of Indiana have had sufficient moisture in the second half of summer (including Lafayette) others are facing dry conditions for a second year in a row.

September is here and so is our typical start to fall fertilization. Many are asking, “should I fertilize drought stressed areas right now?” There are two strategies that could be used. First, you might consider applying 0.75 lbs N/1000 ft2 with some slow release N source. This should help to speed recovery when rains resume but minimize any leaf burn with a lower nitrogen rate and some slow-release nitrogen. Keep in mind that drought stressed plants will not take up nitrogen, and so a response to nitrogen fertilization will only occur after a rainfall occurs and the plant has a chance to take-up the nutrient. Additionally, some injury could occur to drought stressed areas from trafficking equipment across the site while fertilizing. A second strategy would be to wait to fertilize until after the turf greens-up after the next rainfall. Agronomically, the second option makes the most sense. However, some turf professionals may need to begin the fertilization process on some turf areas due to the large number of properties that they manage.

Hopefully, rains will return soon to central Indiana. On the bright side, we could be facing exceptional drought as they are in Oklahoma and Texas. Wow!

Dr. Aaron Patton, Turfgrass Extension Specialist

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Dr. Cale Bigelow Sabbatical

Just a quick note from across the pond. I will be on study-leave/sabbatical for fall semester from 15 Aug. - 31 December, 2011. I will be collaborating with colleagues interested in urban ecology and studying alternative low input turfgrass systems in Europe (primarily the United Kingdom). Please note that during this time I will have limited access to my Purdue email but will do my best to check it at least weekly. Do not be offended if my responses are slow, I have not forgotten about you, things are just slower over here...! If you call my office phone I will be checking that number very infrequently you are better off to send me an email or simply call Jennifer Biehl directly 765-494-8039. In my absence, the Turf Team (Drs. Gibb, Jiang, Latin, Patton, Richmond and of course Ms. Jennifer Biehl) are more than able to help answer any questions you might have regarding turfgrass in Indiana. You can find loads more information on our turf home page.

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Imprelis® Update: Stop Sale, Use, or Removal Order. Q&A

The following post provides an update on Imprelis® herbicide in a Question and Answer format.

Q: What action has the Office of Indiana State Chemist (OISC) recently taken concerning Imprelis®?

A: The OISC issued a stop sale, use, or removal order (SSURO) on August 1, 2011 for the herbicide Imprelis®. The OISC has reason to believe that DuPont Imprelis® Herbicide, EPA Reg. #352-793, when used as directed or in accordance with commonly recognized practice, has caused injury to non-target vegetation, except weeds to which it has been applied, and is therefore MISBRANDED. Therefore, the OISC is hereby issuing a STOP SALE, USE OR REMOVAL ORDER (SSURO) to DuPont Professional Products. This SSURO requires DuPont Professional Products to cease all sale, distribution and use of DuPont Imprelis® Herbicide, EPA Reg. #352-793, in the State of Indiana, effective immediately. This SSURO pertains to any and all quantities and sizes of DuPont Imprelis® Herbicide, EPA Reg. #352-793, within the ownership, control or custody of DuPont Professional Products wherever located. In addition, DuPont Professional Products shall not commence any movement of this product from any present location without prior written approval from the OISC. Any person violating the terms or provisions of this SSURO shall be subject to civil or criminal penalties as set forth in IC 15-16-4.

Q: What is the stance of the United States Environmental Protection Agency (EPA) concerning Imprelis®?

A: On August 11, The EPA issued a SSURO for the herbicide Imprelis®. Previously, the EPA issued a letter to DuPont on August 3, 2011 stating two concerns. First, that the EPA is considering issuing an SSURO (described above). Second, the EPA is concerned about the lack of information that is being provided by DuPont to the public concerning the efficacy of Imprelis®. The EPA “strongly encourages DuPont to reconsider” providing information related to the phytotoxicity studies related to effects on trees. More information about Imprelis, including EPA registration of the herbicide, is available at:

Q: What action has DuPont taken to comply with the OISC?

A: DuPont is implementing a voluntary suspension of sale of Imprelis® herbicide. More information is available at and at (866) 796-4783.

Q: Can I still apply Imprelis® herbicide in Indiana if I have some leftover?

A: No. The SSURO issued by OISC does not allow the continued use of existing Imprelis® herbicide.

Q: What do I do if I have leftover Imprelis® herbicide?

A: DuPont has stated that they will initiate a product return and refund program in mid-August 2011. More details about this will be shared when they become available.

Q: Where can I get more information from DuPont about Imprelis®?

A: Website ( and hotline ((866) 796-4783) are available.

Q: Where can I get more information from Purdue and the OISC about Imprelis®?

A: Read news alerts from the Office of Indiana State Chemist at, read more from the Purdue University Turf Program at, and received updates from the Plant and Pest Diagnostic Laboratory at

Read past documents created on July 22, 2011

A Homeowner’s Guide to Suspected Imprelis® Herbicide Injury in the Landscape

A Turf Professional’s Guide to Suspected Imprelis® Herbicide Injury in the Landscape

Aaron Patton, Turfgrass Extension Specialist

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Turf: Dead or Alive?

Many areas in Indiana have received recent rains to their lawns. Some lawns have greened-up and others are still brown leaving many wondering whether their lawns are dead or alive. Below are some images that illustrate the process of determining whether or not your lawn is dead or alive.

Step 1. In an area of suspected dead turf (brown areas), pull at the brown (dead) leaf blades.

Step 2. After pulling up some of the dead leaf blades, examine the ground closely and look for signs of new growth. All new turf growth comes from the crown of the plant (turf) and these crowns are located at or near the soil surface.

Step 3. If you find new turf emerging in these dead areas then that is good news that your turf will recover from drought and heat injury. If not, wait a few more weeks and reexamine these areas.

Step 4. If no new growth is occurring in areas you might need to reseed these spots. For lawns with bunch-type grasses such as tall fescue and perennial ryegrass, reseed dead spots larger than 3 inches in diameter. For Kentucky bluegrass lawns, reseed dead spots larger than 6 inches in diameter (about the size of your hand, or at least mine). Since Kentucky bluegrass has rhizomes (underground stems) it has a greater recuperative capacity than bunch-type grasses. The photo below shows a bare area between clumps of perennial ryegrass.

Aaron Patton, Turfgrass Extension Specialist

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Certainty Turf Herbicide Label Changes

Monsanto recently updated the Certainty® Turf Herbicide label 2011-1 on packaged goods. These changes are effective on product packaged and shipped after May 2011. All cool season turfgrass uses for Certainty have been removed from the 2011-1 label. The product can still be used on warm-season turf. The label change also adds nursery and landscape recommendations for preplant, directed and over-the-top applications in ornamentals and groundcovers.

Q: What does this mean?

A: Product packaged before these changes can continue to be used according to label directions in cool season turf, but any Certainty® purchased in the future will be labeled only for use in warm-season turf like bermudagrass and zoysiagrass.

Q: Certainty® worked well on yellow nutsedge in Kentucky bluegrass, what should I use now?

A: Many herbicide options are available for sedge control in cool-season turf including bentazon (Basagran), LescoGran), halosulfuron (SedgeHammer, ProSedge, others), mesotrione (Tenacity), sulfentrazone (Dismiss), and sulfentrazone containing herbicides (Echelon, Q4 Plus, Solitare, Surge,TZONE).

Q: Certainty® was labeled for rough bluegrass control in Kentucky bluegrass and creeping bentgrass, what should I use now?

A: Velocity is the only other turf herbicide labeled for rough bluegrass control, but it is only labeled for sod and golf course use. Rough bluegrass control in residential and commercial lawns will now need to be controlled with non-selective applications of glyphosate.

Q: Certainty® was labeled for suppression and partial control of quackgrass. Are there alternatives for selective quackgrass control in cool-season turf?

A: No. Certainty® was the only herbicide labeled for selective control of quackgrass in cool-season turf (primarily Kentucky bluegrass). Quackgrass will now need to be controlled with non-selective applications of glyphosate.

Aaron Patton, Turfgrass Extension Specialist

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DuPont launches Website

This week DuPont launched a new website designed to help answer questions from those who have used Imprelis® and are seeing injury to trees.

The website,, states the following: "As a precaution until we are able to more fully understand the circumstances surrounding reports of tree damage related to Imprelis®, do not apply Imprelis® where Norway Spruce or White Pine are present on, or in close proximity to, the property to be treated. Be careful that no spray treatment, drift or runoff occurs that could make contact with trees, shrubs and other desirable plants, and stay well away from exposed roots and the root zone of trees and shrubs."

Starting August 1, 2011, DuPont is establishing a toll free hotline to take all reports of problems from lawn care professionals, property managers and owners, and golf courses, and to handle any homeowner questions and concerns.

For more information visit

Read a letter (click here) dated July 27, 2011 from Michael McDermott, Global Business Leader, DuPont Professional Products, which provides and update from DuPont on the issue in addition to the facts on their new website linked above.

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Water Restrictions and Managing Turf During Drought

For those in the Indianapolis area, customers of the Department of Waterworks – City of Indianapolis are “asking residential and business customers to not water lawns through Friday, July 29 in the wake of continued lack of rain, high heat, and high water consumption”.

The request is voluntary – initially requested on Wednesday, July 20 – and is targeting lawn irrigation in addition to other summer uses such as water for swimming pools, outdoor recreation, etc.

The water restrictions are not due to a shortage of water in this case but due to infrastructure challenges (water main breaks).

A main reason for the request to stop watering lawns is to reduce the stress on the system and a concern on being able to maintain adequate pressure (for hydrants) in order to assist in the event of a major fire."

We published a few tips last week on how to deal with the high temperatures and drought. Two key points for managing lawns during this period are:
  1. Stay off the turf when it is drought stress. Do not mow or drive across drought stressed turf (see photos below).
  2. Your lawn may be brown from drought, but it is not likely to die unless it goes 4 weeks or more without irrigation/rainfall. Therefore, water once every 2-4 weeks with ½ inch of water to keep turf plant crowns hydrated during drought. This amount of water will not green up the turf, but it will increase its long-term survival during long dry spells. This type of irrigation strategy will help keep your turf alive (although not green) and help comply with the request from the Department of Waterworks.

Vehicle traffic to turf that is drought stress will damage and kill turf in many cases.

Aaron Patton, Turfgrass Extension Specialist
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Many Indiana turf professionals who used the herbicide Imprelis® in the fall of 2010 or spring of 2011 and now are reporting off-target damage to trees and ornamentals in the landscape. Additionally, many homeowners have read an article or seen a news story about a Imprelis®. Below are links for homeowners and for turf professionals that provide answers to frequently asked questions about Imprelis®, provide recommendations on what to do next, and provide additional information on this issue.


Purdue University Press Release, Avoid use of herbicide Imprelis, Purdue experts advise

A Homeowner’s Guide to Suspected Imprelis® Herbicide Injury in the Landscape

Turf Professionals

Purdue University Press Release, Avoid use of herbicide Imprelis, Purdue experts advise

A Homeowner’s Guide to Suspected Imprelis® Herbicide Injury in the Landscape

A Turf Professional’s Guide to Suspected Imprelis® Herbicide Injury in the Landscape

News Alert from the Office of Indiana State Chemist, Imprelis Herbicide Injury to Landscape Trees & Ornamentals

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Turf disease watch

A new posting has been added to Turfcast. See Turfcast ( ) to read more about this post and for a daily summary of risk for several turfgrass diseases.

Rick Latin, Turfgrass Pathologist

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The Heat is On!

Extreme heat is stressing turf areas quickly!

High temperatures cause turf decline

There are many causes of turf decline in the summer, but three primary physiological causes are 1) low photosynthesis rates at high temperatures, 2) lack of sufficient moisture, and 3) photorespiration. Photorespiration occurs instead of photosynthesis at temperatures above 87 °F causing cool-season grasses to use energy instead of making energy. As a result, cool-season grasses don’t make energy well when it is hot out and as a result they don’t grow (roots or shoots) well in hot weather which can lead to a decline in turf quality.

Lack of irrigation causing dormancy in some lawns

Water is critical to the growth of all plants, not just turfgrass. Water is a key part of photosynthesis and respiration reactions as well as many other plant metabolic activities. Turfgrass leaves and shoots are comprised of about 80% water. A lack or water (rainfall or irrigation) will lead to a decrease in growth due to a decrease in photosynthesis and plant respiration and an increase in plant temperature (lack of transpirational cooling; analogous to humans not being able to sweat). Each turf species responds to drought differently. Some grasses such as Kentucky bluegrass enter summer dormancy when soils begin to dry whereas others such as tall fescue can maintain their green color longer during drought.

How should turf be managed during dry spells and drought?

When possible stay off the turf! Limit traffic (including mowing) to minimize crushing of the turfgrass leaves and crowns and causing damage. In order to keep your lawn green during hot and dry periods at least 1.0 inch of water will need to be applied weekly. However, with far less water you can keep your lawn alive. Water once every 2-4 weeks with ½ inch of water to keep turf plant crowns hydrated during drought. This amount of water will not green up the turf, but it will increase its long-term survival during long dry spells.

When irrigating it is best to irrigate early in the morning, but occasional watering at mid-day or early in the morning in order to prevent injury from moisture stress is allowable. Following drought, turf should recover in 1-2 weeks after significant rainfall returns.

This year is looking very similar to last year. Hopefully we will not have extended periods of drought in 2011 and period rains will help keep turf alive and growing.

Damage from vehicle traffic on a drought stressed turf

Drought symptoms are visible right now.

Tall fescue clumps in a brown Kentucky bluegrass lawn under drought stress

Aaron Patton, Turfgrass Extension Specialist
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