> http://agriculture.gouv.fr/IMG/pdf/rapportfin.pdf< Thanks for this. It has some data for corn (maize) as well. I've edited the subject to reflect more accurately what I'm looking for. If I'm reading this right, imid expressed in corn pollen is .75ppb and throughout the plant stem/leaves 3.7ppb. Per Krupke, soil of corn/soy rotation is 4.9ppb. Anybody know where this plant data may be available for soybeans? Where I'm going with this: My bees are on mostly Ag land in a corn/soybean rotation. So far, I have never had a bee-kill or other issue I can attribute to pesticides. I attribute this (my opinion) mostly to the availability of more attractive forage during corn pollination/soybean bloom. To build/improve soil, cover crops will be incorporated into the rotation on the 35 acres immediately surrounding my hives, expanded to 120 acres if successful. This will involve chopping and incorporating the residue of the preceding corn/soybean crop right after harvest, and immediately planting cover crop into the soil/residue. One of the cover crops being considered is crimson clover, a crop not typically treated with imid, but a good nectar/pollen producer. Krupke reported 3.7ppb found in dandelions of unplanted fields (I assume the season after a treated crop), I'm wondering if it would be higher for a cover crop since it is planted into 'fresh' residue/soil instead of the following growing season. I'm trying to figure out if the ppb in plant residue is greater than the 4.9ppb reported in soils. What I'm trying to guesstimate is how much risk is there that planting the cover crop into imid containing soil/residue will result in crimson clover that secretes imid in pollen and nectar that is typically attractive to bees. Dan O'Callaghan Xenia, OH *********************************************** The BEE-L mailing list is powered by L-Soft's renowned LISTSERV(R) list management software. For more information, go to: http://www.lsoft.com/LISTSERV-powered.html