Oust herbicide under threat of new regulations

Oregonians for Food and Shelter has provided this letter to the EPA by certified forester, Bruce Alber on the relabeling of Oust and the effect on Oregon.

By Bruce Alber
January 8, 2009

I am a professional forester with 34 years of experience with forest vegetation management.  I have tested, applied, recommended, prescribed the use, and seen the effects of Sulfometuron methyl (SMM) since its registration in the early 1980s.  It has been used in over hundreds of thousands of acres in the Pacific Northwest states of Oregon, Washington, and Idaho during that time period.

I have attended EPA seminars on spray drift mitigation and observed some of the Spray Drift Task Force research projects at New Mexico State University.

The following are my comments on the RED which need to be considered to help us continue to use this very useful herbicide for the control of weeds that compete with the forest tree seedlings that are replanted after a timber harvest.  Other critical uses we have are in Christmas trees, roadside vegetation control, and industrial weed control.

In forestry, SMM is a very important herbicide or component in herbicide blends that are used to control many weed and grass species that compete for light, water, and nutrients around our newly planted forest seedlings.  Without this weed control, these seedlings die or grow very slowly under this competition and areas are not adequately reforested after the timber is harvested.  We depend upon SMM and other products to grow the next crop of trees for timber, pulp and paper, wildlife habitat, and soil stabilization.

1) Please extend the comment period beyond January 12, 2009 another 60 days.  I did not hear about the RED until mid December 2008 and then the Pacific Northwest experienced the worst winter storm event in over 40 years with wind, snow and ice that persisted for 2-4 weeks.  Now the warm rains have arrived and massive flooding is disrupting lives and transportation all over the region.  An extension would allow more users to study the issue and make further important comments.

2) Is the concept that we can’t do any damage to aquatic vegetation a new one?  Obviously, this is an herbicide and they do damage and kill plants.  This is not an aquatic approved herbicide and we have been protecting streams and their plants since it was labeled.  Current BMPs and state required buffers have worked extremely well to this end.  These buffers are 50-60 feet by air (helicopter) in Washington and Oregon.

A good demonstration of the effectiveness of these buffers is the 2000 study by the Oregon Department of Forestry by Dent and others.  They sampled the streams adjacent to 26 operationally sprayed forest units for several herbicides, often including Sulfometuron methyl.  5 water samples per sprayed unit were taken at time intervals after spraying with a threshold of well under 1 ppb.  24 of the 26 areas sprayed had no detectable traces of any herbicide in each of the 5 tests per unit.  Of the two units that had detectable amounts, they were well under 1 ppb.  When a detection was made, the concentration of herbicide decreased rapidly as time went on due to dilution.  The authors specifically noted that no damage was seen on the succeptable plants near the streams inside the buffer.

In 2007, a study by George Ice and Harold Thistle of NCASI looked at the effectiveness of a vegetative buffer in shielding a stream from herbicide spray drift.  They intentionally maximized the fine, driftable droplet creation by using Beco-mist nozzles that produced a majority of droplets well the under 200 um range.  The helicopter then flew at a higher altitude and sprayed only when the wind would carry the spray pattern directly into the stream area next to the open clear cut.  Their published data show that over 90% of these tiny, driftable droplets were very effectively captured or deflected away from the water by the buffer vegetation.  This was a deliberate test of a worst case scenario that proved that vegetative buffers do an outstanding job of protecting water quality and thus aquatic vegetation.

The RED reports that there were only 35 incidents of off target plant damage in 15 years, 20 probable cases and only 14 possible. The RED also mentioned that about 1.5 million acres per year were sprayed in 1999.  No mention of how many incidents, if any, were damage to aquatic vegetation.  The one specifically cited case is from Idaho where the product was applied to dry soil which then allegedly was moved by high winds to damage crops.  While it is good to tighten up label language to prevent such problems, remember that at the time of this incident, the label prohibited that sort of treatment.  Therefore, the worst case cited was already and illegal application and should not have been done.

3)  The 100 foot by ground and 500 foot buffers are totally unreasonable and will do nothing to increase our already excellent record of protecting water and its associated vegetation.  The AgDrift modeling is cited for establishing these buffers, but I was unable to find in the document which inputs were used to arrive at these numbers.  If these buffer widths are required by the label, then the use of this product will be prevented throughout most states that grow timber from forest lands.  I am sure that that is not the intent of the EPA.

The AgDrift model has numerous inputs that lead to the buffers the EPA has specified and I need to see which were chosen.  I believe some very incorrect assumptions were made in running the model.  Fixed wing aircraft are only allowed when using this product when impregnated on dry fertilizer.  All other uses are allowed only with a helicopter.

In our areas, helicopters are flown at 45-60 mph, usually with nozzles such as the Accu-Flo or others that are classified as coarse or ultra coarse droplet sizes.  The component of droplets generated in the under 120 um size is well under 1% of the total spray volume.  We always observe a hard, clear line between dead vegetation and healthy vegetation on buffers and property line edges that are only a few feet wide – that is, there is not a large wide zone of damaged vegetation.  It is either dead or not damaged.  See photograph #1.

The RED states that the nozzles should be those characterized as medium or coarse.  What would happen to the required buffers if the changes were made to the model reflecting today’s real world useage?  Change the nozzle type to coarse or ultra coarse and run it again, then require that on the new label.  I would be glad to help with real world inputs with your AgDrift expert.

As for ground applications, a lot of work is done by backpack sprayers and a 100 foot buffer is totally unreasonable – they can’t reach that far if they tried, with the wind at their backs.  Powered ground equipment is not usually using crop type TeeJet nozzles, but rather coarse off center nozzles, and low pressure handguns along road shoulders or forest areas.  Again, in Oregon and Washington forest practices rules, the 10-20 foot spray buffers on water are doing a great job in protecting that vegetation.  If no damage is seen, does another 80-90 feet of buffer make it safer than already safe?

These 100 & 500 foot buffers would effectively eliminate the use of this important herbicide on virtually all forest sites in the Pacific Northwest and I suspect that the same would be true in the other forested area of the country.

4) How small a stream and its aquatic vegetation must be buffered?  In the spring spray season here there are lots of small rivulets that have green algae in them.  Should they require a 500 foot buffer?  Why buffer them if they will dry up and the vegetation will die 4-8 weeks later anyway?

5) If we can’t use Sulfometuron methyl, then other older herbicides will be used instead.  Most of the alternative products do not have the excellent ecotoxicity profile that SMM has.  SMM does not accumulate in the soil, it does not move much in the soil profile when applied at current label directions, and its very low use rates keep the environmental load extremely low.  If we have to replace SMM uses with Atrazine, for instance, Atrazine is used at 3-4 lbs a.i. per acre versus the 1-3 ounces a.i. per acre of SMM, a 21 to 64 times greater environmental load of a product more toxic to fish and other animals.

If the use of SMM is virtually eliminated by the RED label changes proposed, then more mechanical scarification by bulldozers or broadcast burning of vegetation will be done.  Hand weeding is not realistic in steep terrain, in heavy vegetation, and must be done several times per year.  The alternatives will produce more carbon dioxide release where heavy equipment or burning is used as well has serious concerns with soil erosion from disturbed soils and duff layers.  Hazards to hand crews such as tripping, falling, breathing exhaust gasses, and cutting dangers are serious and long lasting.

In summary, the label changes included in this RED would virtually eliminate one of the most important herbicides here in the Pacific Northwest, and probably a large part of the entire United States.  We have demonstrated through practice as well as excellent research that these changes are absolutely not necessary and should not be added to the label.


Bruce Alber, CF
Wilbur-Ellis Company

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