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

MRTF Turf and Ornamental Seminar - November 14-15

Turf and Ornamental Seminar

November 14-15, 2012

Daniel Turf Center

West Lafayette, Indiana

Registration Form (PDF Format)

Register on-line at http://mrtf.org/php/Registration.php?pid=5487

Registration Deadline: November 2, 2012

CCH's: Cat. 2 - 5 CCH's; Cat. 3a - 8 CCH's; Cat. 3b - 9 CCH's; Cat. 6 - 3 CCH's; RT - 4 CCH's

Wednesday, November 14

8:00-8:30              Registration

8:30-8:45              Opening comments, Aaron Patton

8:8:45-9:45          All About Turf Seed: Identification, Germination, Planting, Aaron Patton

9:45-10:45           Safe Tree Felling: What You Need To Know, Lindsey Purcell

10:45-11:45         Getting Your Hands Dirty: Learning More About Soils, Quincy Law

11:45-12:45         Lunch (on your own)

12:45-1:40           Selection and Inspection of Spray Hoses and DOT Rules, Fred Whitford

1:40-2:00              DOT Regulation Changes: What You Need to Know, Fred Whitford

2:00-3:00              State Chemist News and Updates, Joe Becovitz

3:00-4:00              Weather Effects on Insects: How Do Insects Cope?, Tim Gibb

Thursday, November 15

8:00-8:30              Turf Jeopardy, Aaron Patton

8:30-9:30              New Tools For Managing Landscape and Ornamental Insect Pests, Cliff Sadof

9:30-10:30           Maintaining Grounds: Keeping Native Species In and Invasives Out, Matt Kraushar

10:30-11:30         Perennial Disappointments: Diseases of Perennial Plants, Janna Beckerman

11:30-12:15         Lunch (provided)

12:15-1:15           Promoting Turf Recovery…Fertilizer Strategies, Seeding and More!, Cale Bigelow

1:15-2:15              Identification and Control of Turf Diseases, Rick Latin

2:15-3:15              Herbicide Update: New Resources and Ingredients, Aaron Patton

If you have any questions or have any special dietary needs please contact Jennifer Biehl at 765-494-8039 or biehlj@purdue.edu

When a GPS Unit Malfunctions

This photo was submitted from a golf course where it was found tunneling into a green.  It is obvious that it is creating some damage but the astute manager was able to find and photograph the beetle in association with the damage.  This combination always makes identification and control recommendations much easier.

The insect was identified as a ‘Fancy Dung Beetle’ in the family Geotrupidae: Bolbocerosoma sp.   It is closely related to the Scarabaidae (Japanese beetles, masked chafers, June beetles etc) that we are very familiar with.  Like the Scarabs, these insects often bore down into the soil to lay their eggs.  Usually Geotrupid beetles select areas very rich in decaying organic matter such as in manure and barn yards.  However, just like people, every so often one will become completely lost.  This one apparently has ended up on a golf green by accident.  

You can see that the beetle has created a bit of a burrow and this may be a concern if many of his kind were to do the same thing on a green.  However, I think this may be just a random occurrence and the damage, a very isolated incident. Why it is where it is nobody knows for sure.  I suspect that it’s GPS system is simply out of whack.


Timothy Gibb, Department of Entomology, Purdue University