Optimisation of an in vitro larvae test to test the effects of plant protection products on honeybee brood (Apis mellifera L.)

Directive 91/414 EEC (2005) concerning the placing of plant protection products on the market calls for a feeding test to be conducted on honeybee larvae to test the effects on honeybees (Apis mellifera L.) exposed to the application of growth-regulating active substances (insect growth regulators, IGR). In the meantime, OECD Guideline 237 (2013) ‘‘Honey bee (Apis mellifera) larval toxicity test, single exposure’’ has been implemented; the OECD Draft Guidance Document (2013) ‘‘Honey bee (Apis mellifera) larval toxicity test, repeated exposure’’ is currently being revised. In 2013, laboratory brood test as Tier 1 test on the risk assessment of the effects of plant protection products on honeybees were conducted for the first time as standard test. The advantage of this standardised method is that the exact quantity of the test substance to which each individual larva is exposed is known. Aupinel et al. (2005, 2007a, b, 2009) played a key role in developing these methods; the methods have been tested and validated by various European test facilities (Brood Ring-trial Group) in accordance with internal INRA protocol (INRA, Unite Experimentale d’Entomologie, le Magneraud, Ministere de la Recherche, Ministere de l’Agriculture, Republique Francaise). The LAVES Institute for Apiculture (LAVES IBCe) took part in the Brood Ring-test Group’s validation of the method in 2008 and, as a result, continued the project ‘‘Optimisation of a larvae test to test the effects of plant protection products on honeybee brood (Apis mellifera L.)’’ until 2011, with financial and technical support from the Federal Office of Consumer Protection and Food Safety (BVL). During the first two years of the project (2008 and 2009), testing focused on acute toxicity; during the final two years of the project, testing centred on chronic toxicity. In all four years of the project, the method was further developed with regard to colony management for the laboratory honeybee brood test, and the reduction and stabilisation of the control mortality of the honeybee brood. The results generated in all four years of the project are summarised in this report.