Inert agricultural spray adjuvants may increase the adverse effects of selected insecticides on honey bees (Apis mellifera L.) under laboratory conditions

Abstract Currently, more than 360 spray adjuvants are registered in Germany (September 2021). Unlike plant protection products (PPPs), not subjected to regulatory risk assessment. In practice, numerous combinations of PPPs and therefore possible. Thus, tank mixtures containing insecticides that classified as non-hazardous bees up the highest approved application rate or concentration may raise pollinator safety concerns when mixed with efficacy increasing applied bee-attractive crops. This study analyzes whether selected “PPP–adjuvant” result increased contact mortality pose an elevated honey bees. To answer this question, we chose six common different classes for laboratory screening. These were then tested a total 30 mixtures, each neonicotinoid (acetamiprid), pyrethroid (lambda-cyhalothrin), diamide (chlorantraniliprole), carbamate (pirimicarb), butenolide (flupyradifurone) formulation. We adapted acute test (OECD Test Guideline 214) our needs, e.g., by using professional chamber realistic exposures. Our results showed that, total, 50% all significantly caged comparison individual insecticides. contrast, none alone affected bee (Cox proportional hazard model, p > 0.05). With four five insecticide formulations, organosilicone surfactant Break-Thru ® S 301 within 72 h (for except chlorantraniliprole). Furthermore, acetamiprid yielded second increases from mixture crop oil LI 700 (hazard ratio = 28.84, < 0.05) 14.66, 0.05), respectively. assess field-realistic setting, field trials should be performed provide exposure scenario under colony conditions.