Is the active ingredient in Orthene for fire ants any different than the active ingredient in Orthene for plant sprays? Or is the difference in the rest of the mix to facilitate its use in the ground? I don't know the answer to that.

It only says 50% of accephate and 50% of other ingredients that are not specified, that is why I have doubts to use it. The one that I have seen using in the forums is 75% acephate, but I could not find it online. There is an Orthene 97 granulated. What percent of acephate does Orthenex have?

I looked at the bottle, Orthenex is only 4% acephate. The question would be... how much is in the final solution, since all of these are concentrates of some sort, intended to be diluted. What exactly is coming out the sprayer after final preparation? And what are the other ingredients? Those could be harmful to the plants, too (oils, etc.)

I do not remember in which forum I read it but from the 75% concentrate a third of a teaspoon of the powder is used for a gallon of water. Making the solution with the 50% has no problem, the challenge is that we do not know what the other ingredients are because it does not say non-active ingredients and as it is for ants, it can be anything. Really the safest is the one that says for ornamental plants and it is the one that does not appear, like the Orthenex that they say that it is not going to sell anymore. If Orthenex is 4%, what does it say about the other ingredients? active or not active? Is it a spray to use like this?

Orthenex is a smelly liquid.. the inert ingredients are just that... not specific. Rather oily. I use two teaspoons in a quart of water with a few drops of dish soap. I use it as my "second" treatment to alternate with the Bayers, which does work for me.But I don't have the serious problems that you do. I really think that you need to look at other approaches, such as growth inhibitors. I am totally not an expert in this area, am fortunate that I have not had to deal with large numbers of resistant pests. Good luck!

---------- Post added at 07:41 AM ---------- Previous post was at 07:16 AM ----------

Just for the record... once pesticides have been used heavily and created resistant pests, the resistance stays even if the pesticide use is reduced or stopped. It's genetic... unless the developed pesticide resistance causes some other problem with the offspring it is there to stay. And those pests can breed, spreading the resistance characteristic outside the initial area so that even people who didn't spray find that when they do, it is ineffective.