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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New Website and Blog for Purdue Turfgrass Program

Since last fall, we have been working on revising our turf website and creating a new blog that could be used to deliver our Turf Tips eNewsletter. Among our goals for the development of the website were to 1) answer the most commonly asked questions by clientele and contain commonly needed information, 2) allow easy access to information, 3) attract clientele with an attractive website and new website technologies including social media (Blog, RSS feeds, Facebook, Twitter, and YouTube videos), and 4) reflect the quality of the turfgrass science program at Purdue University. The goal is that these new tools will help increase traffic to the website and improve our ability to communicate with our clientele. An additional benefit is that the new social media tools will allow us to remain engaged with our alumni and improve undergraduate student recruitment. We hope that you enjoy our new website and blog.

Check it out the new website at:

Check out the new blog at:

Aaron Patton, Turfgrass Extension Specialist

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Hot Topics at a Hot Field Day!

Thanks to all the 530 attendees and 32 exhibitors who attended the Midwest Regional Turfgrass Field Day Tuesday (July 19, 2011) at the W.H. Daniel Turfgrass Research Center in W. Lafayette, IN. We had golf and lawn research tours in the morning, two afternoon tours, and one afternoon workshop and addressed many current topics including new products, herbicide injury to trees and ornamentals, diseases, and more. We heard many good comments regarding the field day and the education provided. The only bad comments were about the temperature and humidity outside. We hope to have a cooler day in 2012.

On behalf of the Midwest Regional Turf Foundation, thank you to all of those who attended!

If you didn’t get a chance to attend this year, we encourage you to pencil in July 17, 2012 on your calendar and attend next year. Numerous research tours and workshops in addition to an outstanding trade show will be available again in 2012.

If you have any questions, comments or suggestions for 2012 let us know: or

Aaron Patton, Turfgrass Extension Specialist and Executive Director of the Midwest Regional Turf Foundation
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Annual bluegrass starting to succumb to summer stress in lawns

Annual bluegrass (Poa annua) is a common weed on golf courses, but is now also becoming a problem on higher mowed turf areas such as lawns and athletic fields. This grass is lighter colored than Kentucky bluegrass and perennial ryegrass and can be identified by its boat-shaped leaf tip and membranous ligule (see Turf Tip on its identification). Annual bluegrass is especially noticeable in May and June because of its prolific seedhead production (Fig. 1).

Poa annua is a winter annual that germinates in the late summer/early fall once soil temperatures fall below 70 °F. Seedlings mature in the fall, overwinter in a vegetative state, and produce seed in late spring and early summer. Annual bluegrass is a prolific seed producer. An individual plant is capable of producing more than 360 viable seeds. The seed may lie dormant in the soil for many years before germinating. Annual bluegrass flowers and produces seed over several months and at any mowing height. It grows well under short days and cool conditions, and it will out-compete most other turf species during late fall and early spring. This grass will typically thin and die out during the heat and drought of summer in Indiana (Fig. 2) although there are perennial types that can survive the summer stress. We are starting to see summer decline of annual bluegrass now as our daily highs start to warm. This may be more problematic in 2011 than normal as many turf areas thinned by last summer’s drought were invaded by annual bluegrass last fall and this spring.

Chemical control of annual bluegrass can be attempted with either preemergence herbicides and/or with a postemergence herbicide called ethofumesate (Prograss). Ethofumesate is applied mainly as a postemergence herbicide, but it exhibits some residual preemergence control. Ethofumesate can be applied to Kentucky bluegrass and perennial ryegrass lawns. Two or three applications of ethofumesate applied between September and November are recommended per year. The applications should be approximately four weeks apart. Results are rarely seen that fall; but are usually observed the following spring. Other research at Purdue has looked at fall applications of mesotrione (Tenacity) as a possible alternative for postemergence control of annual bluegrass. Our research at Purdue suggests that Tenacity can reduce annual bluegrass populations which is consistent with the label language that states “Avoid spraying these turf types (annual bluegrass included) unless control and/or injury can be tolerated.” However, the label stops short of recommending this product for postemergence annual bluegrass control. Read more about this research at Purdue (page 18). Both ethofumesate and mesotrione are general use pesticides meaning that homeowners can purchase these products; however, their limited availability (sold only through professional supply companies) and packaging size (more product than needed for a single lawn) typically means that these products are either not readily available to homeowners or are too expensive for most homeowners. Thus, homeowners are encouraged to hire a professional to make these applications.

Most preemergence herbicides (crabgrass preventers) and Tenacity are labeled for preventative (preemergence) control of annual bluegrass. Application timing is very important, so herbicides must be applied in early fall (late-August or early-September) prior to annual bluegrass germination. A second application will be needed at the normal crabgrass preemergence timing in March to control spring germinating annual bluegrass. This technique may take many years to reduce the annual bluegrass populations and it will not be effective on perennial types of annual bluegrass.

Fig. 1. Annual bluegrass that germinated in a poor quality lawn in the fall, overwintered, and then produced seedheads in the spring.

Fig. 2. Annual bluegrass turning yellow and then brown from summer heat stress.

Aaron Patton, Assistant Professor/Turfgrass Extension Specialist

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Warning: High Numbers of Black Cutworms in Traps

June 28/11. We are reporting very high numbers of black cutworm moths in traps right now. These numbers are, in fact, higher than we have seen in many years.

What this means to you is that there is a possibility that these moths will lay eggs on your turf and the resulting caterpillars may damage your golf course.
We generally do not see black cutworms damage fairways although we know they are feeding there. On bentgrasses, however, damage can become quite severe if populations are high and feeding goes undetected.
We are not suggesting preventative treatments because of the spotty infestations of these insects, but we are suggesting that you be aware of the increased threat right now and monitor bentgrass tees and greens for the presence of the caterpillars.
Larvae are hairless caterpillars with unique markings on the head and body. The upper half of the body is a darker gray than the lower half.

They have black dots along both sides of their body.

Newly hatched cutworms are small but they may grow to a length of 2 inches.
A soap solution (1/2 ounce of liquid dish soap per 3 gallons of water) applied as a drench to the green during the day will flush the caterpillars from below the thatch to the surface where they can be easily seen. If three or more cutworms per square yard are found, a pesticide application may be needed.
If a decision to treat a green or tee is made, remember to also treat a 20-foot border to kill any cutworms that otherwise may crawl onto the green. Research from Wisconsin shows that daily mowing may remove more than 75% of the cutworm eggs before they hatch. However, eggs easily survive the mowing and may hatch where the grass clippings are deposited. It is therefore recommended that clippings be deposited at least 100 yards from susceptible tees or greens to prevent the cutworms from crawling back.

One female black cutworm moth can lay up to 2,000 eggs over a series of several days. The eggs hatch in three to 10 days (depending on temperature) and the young caterpillars begin to feed on the grass shoots. As the caterpillars increase in size, they burrow into the turf and move to and from these holes at night to feed on the grass.
Regular sampling for cutworms and damage, followed by insecticide treatment, if needed, will protect turf grass against significant damage by black cutworms. Chemical control should only be considered when the cutworms are confirmed in high numbers and damage begins to become apparent.
Insecticides recommended for cutworm control include any of the pyrethroids labeled for use in turf.

Tim Gibb, Turfgrass Entomologist
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Herbicide damage on Spruce and Pine - Update

A few weeks ago we posted information on herbicide damage to spruce and pine (link here). We are continuing to see some new cases of damage, but many with affected trees are simply waiting to see whether or not their trees will recover. For those of you who might have trees with suspected injury to the herbicide Imprelis (aminocyclopyrachlor) or other auxinic herbicides, DuPont has issued a press release on managing trees under stress including sections on:

  1. Suggested care of trees showing signs of stress.

  2. Disposing of and replacing trees.

  3. Additional homeowner information.

Please read the linked attachment for full details.

Aaron Patton, Assistant Professor/Turfgrass Extension Specialist

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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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Educational Opportunity:

Educational Opportunity:
Turf Field Day
Tuesday, July 19, 2011
Daniel Turf Center, West Lafayette, IN
Attendee Registration Form
Exhibitor Registration Form
Attendee On-line Registration
Diagnostic Training: Lawn Care
Thursday, July 28, 2011
Daniel Turf Center, West Lafayette, IN
Attendee Registration Form
Attendee On-line Registration
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