Before the DD, I used to spray a bit of diesel on puddles of water on my acerage where mosquito larva might grow. It seemed to work well and I think the small about of oil was not harmful. However, such a practice is not approved by the DD. What if one sprayed cooking oil on standing water. Would that not be harmless and totally organic?

Mosquito dunks are organic. They can dry out and rewet just fine. They carry a disease that kills the larvae but doesn't hurt mammals, birds, or fish.

A small amount of bleach work wonders

As David gently put it - the Mosquito Dunks are highly effective, inexpensive and organic. Bleach in any amount is unacceptable in the organic program. There are many options for controlling mosquito larvae in the Information Center of dirtdoctor.com. Check it out, I think you will find it usefull.

Wells Brothers in Plano carries a BTI product which has small granules that are easily spread around on the ground. This is how cities in the Northeast part of the US control mosquitos that breed in the pools of standing water that are left when the snow melts. This type of material is spread from airplanes.

You ask an interesting question that I don't think anyone has answered. Is there a safe, very light weight oil that can be used to prevent the mosquito larva from hatching? Does anyone know?

Marlyn