View Full Version : Surfactant for broadleaf herbicide

10-09-2002, 11:12 PM
I recently ran out of my usual spreader and had to run to the local ag center for some more. I couldn't find anything like what I normally use and could only find crop oil. I was in a pinch and used it and it seemed to work just fine. Since the price is about 1/3 the cost of my usual spreader, I am considering using it all of the time. Anyone have any thoughts as to the wisdom of doing this?

10-10-2002, 12:05 AM
One big question: Is it labelled for only ag use? Or also for ornamental turf?

10-10-2002, 12:34 AM
Whats the difference? If it works, it works.

10-10-2002, 04:34 AM
There is a MAJOR difference. Labels are legal documents specifying the use of a product. In the case of lawn care, there are many products also used in agriculture. You might be able to purchase an ag-labelled 2,4-D product for 2/3 the cost of the same manufacturer's turf 2,4-D formulation.

So it's the same product, who cares? Your state pesticide regulators would care. To the tune of several hundreds or thousands of dollars.

10-10-2002, 09:17 AM
Jim is correct with respect to the legality of AG only labeling.

But there is a difference in make up too.

Crop Oils are designed to only lower the surface tension of the spray residue & "lay out" the spray better. Like making water wetter. This is how soap helps us get our hands cleaner than water alone. Some also increase cuticle penetration. And this is fine.

But "Spreader Stickers" also contain compounds that help the finished spray residue resist washing off after the spray has dried. That's important if rains are in the forecast but you don't feel lilke getting behind in the route.

More stuff in the bottle = more cost.

What costs more? Skips, retreats, or Spreader Sticker?


10-10-2002, 09:59 AM
Thank you all for your responses. First of all let me assure everyone that I would never use ANY product in a manner contrary to label instructions. I understand the meaning of being penny wise and pound foolish. This particular label had no limits as to its uses.

Tremor-I would appreciate some follow up to one of your comments. I may have misled you as to my usual product. I wrote that it was a "spreader" when in fact it is labeled as a penetrant. My thinking at the time of purchase of the crop oil was that doing applications this time of year a penetrant would not be necessary. I would definately use a product with a penetrant with mature weeds, dry conditions, etc. but with cooler weather and rain we have had recently the weeds seem to be vulnerable. Is that sound logic? Also, I've heard various opinions as to how long a post emergent broadleaf herbicide needs to sit on the leaf in order to be effective. I've heard anywhere from 30 minutes to 24 hours. I know that 24 hours would be ideal but in this business you can't always do aps under ideal conditions. I also know that there are numerous variables involved in that as well but generally speaking, what would be an adaquate amount of time for product to work?

I direct these to Tremor but I would appreciate anyones input or experience.

10-10-2002, 10:25 AM
Thanks for answering my quesion:)

10-10-2002, 11:25 AM
Hi Decali & Welcome to LS,

I agree with your logic.
Right now it is cool where I am. Soil moisture is back up too, so there are plenty of young winter anual & perennial weeds germinating out there.

During periods of good growth (like now), 30 minutes is probably long enough in most cases for acceptable kill of the easier weeds (dandes, clover, etc).

Are you spraying an amine or ester right now?
Esters do a great job in the cooler temps & may do a better job right now without a surfactant than an amine with one.

But I'm also assuming we're dealing with phenoxy herb.'s.

What are you spraying for & with?


10-11-2002, 08:15 AM
We use different mixes and products depending on the time of year. Right now the broadleafs we're mainly dealing with are henbit, chickweed, dandelion. We're putting down a product with pre and post emergent activity mixed with a 3 way amine. When it cools a little more we go with Tryclopyr/2,4-D ester product which works really well.You mentioned in an earlier post that a surfactant may not be necessary when using the ester formulation. Could you expand on that? Also, some of the ag people in my area add a small amount of sulfate of ammonia to broadleaf mixes to increase effectiveness. Everyone I ask about it either doesn't know why it's done or has never heard of doing it. Can you shed some light?

10-11-2002, 01:23 PM

Ammonium Sulfate 21-0-0 24S is sometimes added to herbicides at rates of 1/8 to 1 lb of N. This would have the same affect on the turf as any other fertilizer. But it seems more common in the parts of the country that are either cool during the times weeds are being treated, or where sulfur is often found to be deficient.
We have neither sulfur deficiencies nor enough AG left around here to influence the shipment of AS to this area. So the practice has never caught on in the Northeast.
The practice probably came from some old farmer noticing that his herbicide worked better in cool weather if he was "spraying out" some AS he had hanging around. Since it helped kill weeds, the practice spread.
The incidental improvement to turf quality was probably why the process continues today since other means of speeding up herbicides are available & other sources of N are less freight sensitive. But I would have to say that in areas that are not wanting for Sulfur, the practice would be better served by UREA. At 46%N, it is more than double the analysis, so the freight savings make urea more attractive. And on our acidic soils (Northeast), S is rarely offered to turf in these high (24%) numbers.

The weed controlling effect is that of speeding up the growth of the targetted weed. And that aids in the translocation of the herbicide. An process that speeds up the growth will improve the weed control

I wasn't knocking the use of amine herbicides with or without sticker/extenders. I just feel that Ester based herbicides are MUCH quicker to penetrate the leaf cuticle than amines. Particularly on weeds that have a durable/waxy leaf cuticle. This type of weed (locally, violets come to mind) is able to resist the penetration of the amine salts of 2,4-d & other phenoxy herbicides, lowering their efficacy. So if Hard to control weeds are present or if speed is important (either due to cool weather or the threat of rain), I can't see not using the esters.
Due to the volatility of esters, the amines are the way to go when temps are above 75*F.
Around here today, the temp is 55*F & raining. Given a 20 minute break in the rain, one could easily kill weeds with an ester based 2,4-d spray before the rain returned & washed the spray off the leaves. But the kill would occur anyway. And having a sticker present wouldn't have helped unless the spray had dried. And that wouldn't happen around here today.

Does this help?