Who do I contact to report this very bad issue. These 3 trees were very prosperous and growing very well. They are well established trees but now are dying

My own experiences with Sevin have been fantastic. Works like a charm -- except when the problem is not insects. Maybe your trees have a fungal issue? Sevin won't do a thing to combat fungus. You might try spraying the trees with a fungicide, as directed on the bottle. A hose attachment application would probably work best on trees, so you can reach the upper branches.

Lartam, do you have pics of the trees? Did they have an insect issue for which you sprayed the Sevin? Were they doing poorly before you sprayed? Were you just letting the rain water them, or did you water on a regular basis? As Jaime has said, I don't think spraying Sevin killed your trees. Sevin is an established product and has been around for years.As far as taking care of insect issues, it does the job well, and I have never heard of it killing any plants of trees it was sprayed on. Im thinking the trees were already dying from some sort of disease or mechanical damage before they were sprayed.

Contact your State Agr. folks or local Master Gardener folks to check it out before going to the Sevin manufacture. They can take a look at the issue first and if it's the product advise you. Climate change can do strange things. Why did you use Sevin on your trees?

Sevin is an apicide, it kills bees and other Apoideas (bees, bumblebees and wasps). It is one reason that bee populations are in catastrophic decline. Please don't use Sevin or other apicides. There are other ways to deal with insect problems.

No bees, no food.

I have used liquid sevin for years on my shrubs/trees for japanese beetles and such and I have never had it harm anything I put it on. Ever. I suppose its possible if a plant was sprayed during very high on sun that the leaves could burn from water spots and turn brown, but that would not kill it or have anything to do with sevin.

Henderman said:
Sevin is an apicide, it kills bees and other Apoideas (bees, bumblebees and wasps). It is one reason that bee populations are in catastrophic decline. Please don't use Sevin or other apicides. There are other ways to deal with insect problems.

No bees, no food.

Something of interest... remember that disaster in Bhopal?

Do you know what that factory was producing ?

Yup... sevin.

Dou really want to have that kind of impact on the rest of the world?

A few bugs in my garden?

A non-issue.

When we stop using chems in the garden, Nature eventually balances back out... again.

If we never use any of that stuff... nature doesn't have to recover... the balance doesn't get toppled.

I agree with Henderman and Stone.