Actellic 50EC (pirimiphos-methyl) can no longer be applied to store structures using a knapsack sprayer, after new operator exposure studies produced unexpected levels of over-exposure, Syngenta says.

The product can still be used as an admixture on grains, while the smoke generator formulation can be used to treat structural surfaces and grain by automated means.

The study results do not represent a current or past health risk to operators, the firm’s Lionel Stanbrook insists. “It does constitute a regulatory exceedance.” But the regulatory operator exposure assessment is conservative and assumes the product would be applied every day for at least 12 weeks, he says.