[camero7]

Maybe this is why bees are doing well around corn and canola. The sensationalists are going to have to find another whipping boy.

http://entomologytoday.org/2014/02/06/neonicotinoids-barely-found-in-pollen-of-seed-treated-plants/

When the researchers tested corn, one neonic was not found at all in the pollen; two others were found, but at extremely low levels, with the highest having a mean of 2.3 parts per billion. To put that into perspective, one part per billion equals one second in 32 years.
When they tested soybean flowers and cotton nectar, they found no traces at all.
“It’s not being expressed in the reproductive parts of the plants,” said Dr. Lorenz.

 

[BernhardHeuvel]

So what's the LD50 in parts per billion for bees of certain neonics?

 

[Tenbears]

The problem has not been weather neonic's transcended the cellular barrier and were present in pollen. We have known for a long time they do not in a significant amount. the main concern has been in drift during application. Direct contact with the dust that settles on nearby plants in bloom have been the main concern. I come from a 6 generation farm family, although we try to follow low drift recommendations Ie: planting early morning when dew is on, and on wind free or low wind days, It is not always possible or practical to do so. That is where the problem lies. The division between responsible farming, and profitable farming.

 

[BernhardHeuvel]

For Imidacloprid it is:

LD50 oral
8 ng per bee (EXTOXNET database)
5 ng per bee (Suchail et al., 1999)

LD50 chronic
0.01–1.0 ng per honeybee (Suchail et al. 2001)
or 4*8 μg/L (Dechaume*Moncharmont 2003)

Odoux found a consumption of 10-20 kg of maize pollen per year, and honey bee colony established (Odoux et al. 2004). At a concentration of 2.1 ppb in maize pollen (BONMATIN et al. 2005) which adds 0.000000021 kilograms IMIDACLOPRID (21,000 ng IMIDACLOPRID) on maize pollen registered active ingredient in a honey bee hive. Estimates according to a study on consumption of honey bees, depending on age, gender and caste different amounts of IMIDACLOPRID on nectar, honey and pollen (RORTAIS et al. 2005). With an estimated concentration of 4.75 pg (0.00475 ng) IMIDACLOPRID per 1 mg honey / nectar and 3.4 pg (0.0034 ng) per 1 mg of pollen consume honeybee workers as short-lived summer bee 0.3 ng IMIDACLOPRID as larva , 0.5 ng as a wax producer, 1,31,9 ng as a brood nurse and 1.1 4.3 ng as a forager. A short-lived summer bee consumes thus a total amount of 3.2 ng to 7 ng IMIDACLOPRID exposed during their lifetime on the consumption of nectar, honey and pollen. A winter bee is more durable than the summer bee and therefore consumes more pollen and honey as the summer bee. So it takes 0.3 ng IMIDACLOPRID as a larva, 1,31,9 ng IMIDACLOPRID as breeding nurse, 1,14,3 ng IMIDACLOPRID as a collector and 3.8 ng IMIDACLOPRID as a wintering bee. Overall, the winter bee consumed 6.5 ng to 10.3 ng IMIDACLOPRID during their lifetime on the consumption of nectar, honey and pollen.

Summer Bee = 3.2 ng to 7 ng IMIDACLOPRID
Winter bee = 6.5 ng to 10.3 ng IMIDACLOPRID

Roughly the lethal chronic dosis is 1/100 of the LD50 with most neonics. As a rule of thumb. Bottom line, this stuff is extremely toxic compared to regular insectides. That is why it is a seller. :thumbsup: