The 29 April vote on continuing use of neonicotinoids is still in the balance, says NFU horticultural advisor Dr Chris Hartfield.
While scientific studies show that dosing bees in the laboratory with neonicotinoids has harmful effects on their behaviour and life cycles, other studies, including one published by Defra last month, show these harmful effects are not seen under normal field conditions, Hartfield said.
He said there were range of scenarios likely at the EC appeals commitee meeting but "it is difficult to see how it will go vote-wise".
The original vote was split 50/50 for and against/abstentions, with the UK abstaining.
The actives under threat are imidacloprid, clothianidin and thiamethoxam on crops attractive to bees.