Do PGR's In Turf Harm Trees?

[Tony alony]

I've read mixed reviews on using PGR's on your turf if you have trees in the lawn as well.
Are trees affected in any way by PGR's within their root zone. It has been written/ suggested that a tree's leaf production can be hindered. Leaf production provides photosynthesis for the tree, and PGR's somehow limit limb elongation, hence, leaf production. It seems obvious that a tree can out compete grass, so I just wondered. Any thoughts would be appreciated.
Thanks for any replies.

[Tony alony]

Just found this article : http://www.arborsystems.com/PDF/researc ... tility.pdf
Now I'm really confused.

[osuturfman]

I honestly can't say I have ever seen, heard, or read about turf PGRs having negative impact on trees. Mastiff, which you referenced in your second post, is actually marketed in turfgrass as Cutless. Cutless is widely used on golf turf to reduce Poa annua populations and reduce growth of other grasses.

Do you have any information regarding injury to trees as a result of PGR use?

For Primo (trinexanpac-ethyl), the most widely used PGR within this group, due to it entering the plant via foliage, I would imagine one would have to try pretty hard to get it on tree foliage. That said, there are other PGRs like Cutless and Trimmit (paclobutrazol) that enter the plant through the roots.

Below is a good presentation regarding the use and crossover of PGRs between turf and landscape.

http://www.ipmnet.org/tim/pesticide_ed/ ... lators.pdf

[Tony alony]

Thanks for your response, osuturfman. Yes, I have seen the reference link you provided. I once used the same link in a topic discussion in order to prove my displeasure with PGR'S on St. Augustine grass. I can't seem to find the link in my bookmarks where I read that one of the root absorption PGR'S was harmful to trees, meaning; unintended exposure.
I honestly don't know much about PGR'S, that's why I asked.
Another question I have about their safety/usage is in really hot climates. Apparently, there are a number of products that may be suitable and safe for use on St. Augustine, as seen here: http://www.scstma.org/upkeep/resources/ ... 202006.pdf. (see page 75).

Thanks again for your response.