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Discussion in 'Pesticide & Herbicide Application' started by macaw, Jan 21, 2004.
Preen is more of a homeowner Pre-emergent herbicide. I prefer something stronger.
For areas where I want to kill all leafy vegitation (but not woody vegitation), we use Casoron 4G. Good stuff. Nasty. But good. It's more than just a pre-emergent. It's also a post-emergent. It will kill existing vegitation as well as preventing vegitation. It'll prevent weeds for at least a year. Unfortunately, it also kills perennials, annuals, and harms even some sensitive woody plants. It's best used for areas where you don't want anything to grow. e.g. a gravel path. Also, most chemicals leech downhill. So you never want to put something strong like Casoron uphill of something important (like turfgrass). Water will cause it to leech downward. So you have to be especially cautious there's NOTHING downhill in any direction (including neighbors) that could get killed.
For more sensitive areas where Cassaron isn't an option, we choose Snapshot or Ronstar. These aren't quite as strong and are solely pre-emergents. They also don't last as long as casoron. But they also don't do as much damage to existing vegitation.
HERE is an excellent article about pre-emergents from a company here in OR called Seed Research - a very well respected co. in our industry.
I;ve used snapshot and preen as well...results were better than if nothing at all was used. But as mentioned, its not 100% effective but it beats not doing it at all.
Make sure you put it down at just the right time...better a little early than too late.
Preen is an excellent control for most grassy weeds and a few broadleaf weeds. The active ingredient is treflan [ trifluralin]. If you have lots of broadleaf weeds as well try Woodace Preen Plus [formerely Professional Preen]. This has not only trifluralin but also Gallery or isoxaben to control the broadleafs. Excellent control over a greater weed spectrum.
Pre-M / Pendulum, [pendimethalin] and Barricade, [prodiamine] are also OK but control mostly grassy weeds. There may be some advantages in certain situations to using these because they can be used in a spray application for difficult to reach areas.
What about surflan?
Surflan [orizalin] is great stuff for spray applications. Availability has been an issue and Dow recently sold Surflan to another second tier chemical company. Apparently one of the intermediary reaction products in the manufacture of Surflan is nitroglycerin. I think there have been two explosions associated with Surflan production that have affected supply. Kaboom!
If you can get it give it a try. It has been a long time since I used Surflan and I can not comment on the cost / benefit. I know the length of control and to some degree the weed spectrum are dependant on rate.
One great use for Surflan is to mix with Roundup or other glyphosate product for edging and fence lines etc. This prevents regrowth. This would also be a great cocktail to use when doing follow up directed spot sprays behind your granular preemergent application.
Best of luck!
We used to use Surflan too. But I got away from it because it was so labor intensive.
With granulars, it's simple to just place the product into a hand held gravity spready and go. (No. I am not talking about one of those whirly-bird hand fertilzer spreaders.)
Labor time for spreading granular products is 1/5 the time to spray.
There are lots of pre-emergents for legitimat applicators to use in beds: Pennant, Snapshot, Ronstar, Professional Preen, Treflan are a few to start.
Anyone using consumer over the counter products like Lebanon's Preen is probably not licensed, insured, or educated in the proper use of pesticides. It is much more expensive to use consumer grade products, because of the generally much lower percentage of active ingredient.
Also, Preen is ancient technology - one of the oldest mainly grassy pre-ems, and it controls a couple of dozen or so weeds. Snapshot controls around 100.
Another assumption. When you can catch good deals on the stuff like $1 for 5lb container when stores have closeouts on items, darn right ill use it.
Thats the only reason i use preen, all other times i use Snapshot
Actually Preen is trifluralin 1.875% active and you can buy Treflan 5G if you want a bargain. With the higher load you don't get as many particles per square foot. Woodace Preen Pro is the exact same formula as Snapshot but with a lower loading so you get more granules per square foot.
Be careful with that Casoron! I watched a guy resod around all the shrub beds on an entire condominium complex once because he was a little sloppy with a Casaron application. It will move through the soil with water after application so be careful of embankments as well.