how long for herbicides and pesticides to break down

I've got a couple problems and wondering if any experts might know how long it takes for these things to break down  and place can be organic.
the place I plowed up for a garden this year was sprayed with herbicide by power company contractors. I spent a bunch off work on the space plowing it up last year and putting buckwheat cover crop last year and getting it ready this spring. right as beans and peas were flowering it all got sprayed and I never saw the people who did it,, AARRG.  #%&^%#(&&^%%%^^  I never expected that they would come on my property and spray but it is under power lines.

also does anyone know how long it takes for DELTA DUST to become inert after being used

According to it's sales blerb for Delta dust it's effective for 8 months, so I would hazard a guess at at least double that for it to be gone.

If you want Organic certification it's normally 3 years, however you may have a bigger problem if they sprayed beans and peas then I assume it was an obvious garden and they may just spray it whenever they want.

Yup, that would make me angry too (incandescent, or thermonuclear, is closer).

The contractors/subcontractors who do the actual work may be highly professional, or may be the lowest bid outfit that really doesn't give a rat's patoot. I suspect you got door #2. Oy.

But to briefly step away from the mushroom cloud: as a rule, ultility rights of way allow exactly that -- the razing of anything that interferes with access to the lines. Up here, they come around as a courtesy and work out a plan that is acceptable to all. But they hold the hammer, and are within their rights to mulch/spray the whole zone.

So, to do anything in that zone, you have to play ball and engage with the utility company. If possible, do it well beforehand. It may take some patience to get in contact with someone who has the authority to make decisions.

Then, a permanent note can be attached in the work order system, linked to your property location and address. This will pop up when work orders are issued. Subs usually take these seriously. Signage is likely needed as well.

None of this helps you right now, sorry. But it's sort of how the system works.

For Organic certification the government says 3yrs after the big industries lobbied them. So it is probably 7yrs if not more.

Have you posted a "no spray" sign? In Kansas one can get a 'Sensitive Crop Grown Here' signs. I do not know if having a sign would work but one can always try.

I like the idea of a sign. The electric company here has an easement/right of way on my farm, and I maintain the growth under their power line. I've had the idea of making a fence sign that says something to the effect of "organic farm, do not spray. Landowner is maintaining growth under power line. For questions or access to prune tree canopy contact so-and-so". Something where I have clearly stated in a nice way what my desires are so they know. I think if there is no sign or if I never contact the power company and talk to them, then I guess they'll treat my place the same as any other.

I agree that signs are good, but compliance is totally discretionary.

In contrast, the conditions on the company work order determine who gets paid and who is legally and financially liable for mistakes. It gets the attention of the various players.