EPA Upholds Lorsban (Chlorpyrifos) Registrations And Retains All Uses.
BAD NEWS FOR BORERS
Mike
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Chlorpyrifos is an extreme pesticide and highly regulated here in California. I’m disappointed it is still available in some states w/o an applicator’s license.
The problem is you need to grow a tremendous amount of peaches to ever use one package of the stuff and they are the only species I manage where borers have been a big enough problem to go with the big gun. A TBS is enough to protect about a hundred trees for a year.
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I’ve started just waiting for the my peach trees to start oozing sap at the base, then use Lorsban as a rescue treatment. Lately, that seems to be working pretty well.
I believe all liquid formulations of Lorsban are Restricted Use nationally. The water soluble packs are not Restricted Use. I think because theoretically the loader/mixer isn’t as likely come into contact with the concentrate in a WSP.
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Or is it because the WSP has less concentration? I couldn’t find a WSP label.
Water soluble packs also have a much longer shelf-life, I believe. I have some Lorsban left that must be 20 years old. Now I back it up with a pyrethroid when I spray the base of my trees in my nursery once a year. Still working with the back-up, but I won’t risk it alone.
That’s my fault. I thought they listed the water soluble packs under the WSP suffix, but for some reason they list it under water dispersible granules (WG) suffix. Here is the label.
This would be the 75% active ingredient formulation, so it’s actually a bit more concentrated than the liquid formulations (which are RU). The rate for the 75wg would be 4 lbs. per 100 gal. of water. The WG packs come in a real odd ball size (1.33 lbs.) which makes 33 gals. of spray mix, which will treat a lot of trees for borers. As Alan alluded, a little goes a long way.
You can get 50 lb bags of chlorpyrifos for turf but it’s really weak stuff.
http://www.pestrong.com/1083-sa50-chlorpyrifos-25-granular-insecticide-50-lbs.html
Of course there has been a lot of negative news about chlorpyrifos lately (I’ve seen it mentioned twice on CBS in the last week or so) because of the studies suggesting it’s bad for children. Really though the label is pretty tight. It’s hardly labeled for any foliar sprays on fruits, strawberries and tart cherries excepted, and even those are only labeled for very early sprays, giving plenty of time for wash off and degradation. Chlorpyrifos also has a very low leach potential, so in my opinion the hoopla was a bit over blown.
Not trying to start a debate with anyone, just explaining why I have no problem using it.
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The liquid Chlorpyrifos I’ve purchased in the past is 54% (not RU) with signal word Danger. One of the labeled uses out here is for control of ACP.
I believe in continues to be sold online without any verification of applicators license. This is a tragedy because overuse is a serious environmental problem.
Is that an old formulation? I couldn’t find any liquid formulation w/ 54% a.i. As far as I know all the liquid chlorpyrifos products sold now are RU.
It wouldn’t bother me if all the formulations of chlorpyrifos became RU (although I’ll admit the extra record keeping is a hassle). To me the biggest misuse are all the chemicals (including chlorpyrifos) and fertilizer applied to turf, just so we can see/walk on the weed free turf. It just seems silly to me, but then again I’m not a golfer and only mow my lawn when I’m worried the grass is getting too tall for my mower to buzz through quickly (my wife has different ideas).
This old fiction pretty much sums up how I feel about lawn care.
http://www.chicagonow.com/waterdog-journal/2011/06/god-and-lawn-care/
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Yes. 
That’s because I transposed digits! I was thinking of Quali-Pro Chlorpyriphos 42.5%
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Thanks. Was it always RU? I know chlorpyrifos has come under increasing regulatory control. It used to be an over the counter for termites.
It’s ready to mix.
Richard,
I’m not following. The link you posted for Quali Pro was Restricted Use (RU) on the label.
“Ready to mix.” What does that mean in terms of Restricted Use?
Btw, this is an edited post. I misread your last post.
I took your “RU” to mean Ready to Use! 
In California, that formulation has always been Restricted Use – but as you know some states historically were slow to restrict ag pesticides until the EPA came into the picture.
Yes, I also remember an over-the-counter termite product containing a small dosage of chlorpyrifos. It seems a decade or so ago that it came off the retail shelves.
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