All you will ever want to know from an independent source on imid..

http://www.cdpr.ca.gov/docs/emon/pubs/fatememo/imid.pdf

The half-life of any pesticide is actually a range, since it can be long 
or short depending on the conditions. Generally speaking, the half-life 
of imid. is 49-190 days, but it can last much longer or much shorter, a 
few days to 600+ days, it all depends on the conditions. If you take the 
high end of 190, that will result in at least 1/4 remaining a year 
later, so it would not be unusual to find it in the soil at measurable 
amounts at the time of the next application. It is not supposed to 
disappear before the labeled half-life since it will only be reduced by 
half. If you measure ppb, it will be around for a very long time, along 
with everything else you put in the field.

Bill Truesdell
Bath, Maine

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