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MSMA Update for Turfgrass Applications: EPA Revisions

Original Source: 
Patrick McCullough, Extension Specialists, University of Georgia
Original Source: 
Clint Waltz, Extension Specialists, University of Georgia

In January 2009, the Environmental Protection Agency (EPA) passed new regulations on future use of MSMA for weed control in turfgrasses. Several misinterpretations of the reregistration decision by the EPA have been sent throughout the turfgrass community. This alert addresses these misinterpretations and clarifies details of new regulations passed by the EPA for MSMA use in turf.

Residential and Athletic Field Turf

Effective January 1, 2010, MSMA will no longer be labeled for use on residential turf, drainage ditch banks, railroad, pipeline, and utility rights-of-way, fence rows, storage yards, and similar non-crop areas. Any previously purchased stocks of MSMA products may be applied until December 31, 2010.

Golf Courses, Sod Farms, and Highways

All uses of MSMA and all currently registered uses of DSMA, CAMA, and DMA may be used until December 31, 2009. MSMA use on golf courses, sod farms, and highway rights-of-way will be cancelled as of December 31, 2012. Use of existing MSMA stock will be allowed until December 31, 2013. Golf course use is limited to spot treatments not to exceed 100 square feet per spot, or 25% of total golf course acreage per year. One broadcast application is allowed for newly constructed golf courses and sod farm use is limited to no more than two broadcast applications per season. A 25-foot buffer zone must be maintained around permanent water bodies. Only two broadcast applications per year are allowed for use on highway rights-of-way and a 100-foot buffer zone must be maintained around permanent water bodies.

The use of MSMA in turf continues to be a fluid situation as further clarification and understanding is determined. When additional information becomes available, it will be provided and posted on To see the current EPA’s amendment to organic arsenical herbicides, please visit

Please share this information with others in the landscape & turf industry.

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Volcano Mulching: an Erupting Problem in the Landscape

Original Source: 
Ellen Bauske, Program Coordinator, Center for Urban Agriculture
Original Source: 
Willie Chance, Outreach Coordinator, Center for Urban Agriculture

Landscapers often apply a thick layer of mulch around trees in a ring. When this mulch is piled against the trunk, this is called a mulch volcano. Though this is better than having no mulch at all, mulch volcanoes can cause several health problems for trees.


Mulch helps trees in several ways:

·         Controls weeds and keeps soil moist

·         Moderates very high or low soil temperatures.

·         Improves tree roots and overall tree health.

·         Reduces trunk injury and soil compaction from equipment.


However, according to Chris Starbuck at the University of Missouri, mulch volcanoes can severely drought stress newly planted trees.


1. Mulch volcanoes encourage poor root growth. Roots buried by the mulch volcano die due to lack of oxygen in the water-logged soil. At the same time, growing conditions in the top of the mulch are temporarily favorable for root growth. This causes roots to grow upward instead of downward. Mulch does not hold water as well as soil and eventually dries out. This stresses the tree’s roots and puts the tree into severe drought stress.


2. The mulch volcano can also act as an umbrella, shedding water to the surrounding soil.  Fungal activity in the surface of mulch volcanoes can make the mulch repel water. Water then runs off the volcano, rather than moving into it. This usually happens more with mulches that are high in carbon like ground wood, wood chips or sawdust. It also happens with bark mulches. Since new trees have few roots the root ball must be kept moist. Volcano mulching can keep irrigation and rain from the root ball and lead to severe drought stress even if the tree has a regular water supply.


3.  Mulch volcanoes encourage fungal canker diseases. Starbuck also notes that mulch volcanoes keep the base of the tree constantly moist. Trees are also stressed because the cells in the bark of the tree cannot get enough oxygen. This can cause bark decay. Finally, volcano mulching harbors termites and rodents that may attack the tree.


Once the trunk is damaged, there is usually little that can be done to reverse the damage. Avoid mulch volcanoes when mulching. Do not pile mulch around the base of the tree. Apply a two to three inch mulch evenly around the tree, preferably out to the edge of the drip line.


     incorrect mulching


 correct mulching