Ok I know this stuff is banned (at least it cannot be sold in Canada) and I believe worldwide production has ceased.
However, I have several litres kicking around and I have used it in the past for big problems - like a anthill and some tiny little caterpillars that defoliate an ornamental "snowball" tree in the backyard, and where nothing else worked. From what I understand it kills everything which is why I am try to limit its use. However it does work well to kill certain pests. I use only one to a few tablespoons a year so I think I have enough to last decades.

What dangers (if any) does this pose to citrus trees ? I know it kills of honeybees, which is already a big issue and I certainly would not use it directly on anything I would eat or flowering trees - what about its use for things like spider mites and mealy bugs and scale?

Input appreciated.

Greg

http://npic.orst.edu/factsheets/diazinon.pdf

Diazinon, is classified toxicity class II - moderately toxic, or toxicity class III - slightly toxic. It only requires the signal word "warning" or caution". Diazinon is a nonsystemic organophosphate insecticide used to control cockroaches, silverfish, ants, and fleas in residential, non-food buildings. Bait is used to control scavenger yellow jackets in the western U.S. It is used on farms to control a wide variety of sucking and leaf eating insects. It is used on rice, fruit trees, sugarcane, corn, tobacco, potatoes and on horticultural plants. It is also an ingredient in pest strips. Diazinon has veterinary uses against fleas and ticks. It is available in dust, granules, seed dressings, wettable powder, and mollifiable solution formulations. I am not sure, but I do not think Diazinon has been taken off the market. Our ""friends"" the EPA has moved various insecticides and herbicides to restricted use status, but a restricted use licenses is EXTREMELY easy to obtain. Just about every farmer in the United States has a RUP licenses. I believe Diazinon 14G which has long been used is still EPA active. - Millet

Diazinon can degrade in storage, especially if it is in a metal container. I analyzed a human poision case where someone had drank some diazinon left behind by a pesticide applicator-- fortunately for the guy that drank it, much of it had degraded due to storage in a 5 gal metal container for about 5 years--he survived. We identified dozens of rearrangement products in the container he drank from (a whiskey bottle), most of those reactions were catalyzed by iron. Since it is an OP, it is toxic to pretty much everything, but it does not have a really long half-life in the environment (generally days to weeks).