IMBECU   20882
INSTITUTO DE MEDICINA Y BIOLOGIA EXPERIMENTAL DE CUYO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Large-scale field study approach to assess side-effects of the insecticide Spirotetramat to honey bee colonies under a realistic field scenario in a melon crop
Autor/es:
STADLER, T.; MAUS, CH.
Lugar:
Boston
Reunión:
Congreso; SETAC North America 32nd Annual Meeting. Navigating Environmental Challenges: Historical Lessons Guiding Future Directions; 2011
Institución organizadora:
Setac
Resumen:
Spirotetramat (Movento®) is an insecticide which acts as a lipid biosynthesis inhibitor that is being used on a great variety of crops to control a broad spectrum of sucking pests. An intrinsic larvicidal potential of the compound was shown in lower tier tests with artificial exposure conditions (confinement or feeding of very high concentrations).  In order to achieve higher-tier data to conduct a scientifically sound risk assessment of actual field use, a replicated large-scale field trial design was developed to test for potential side effects under realistic use conditions of the product. The study was conducted in  western Argentina. Two application scenarios were tested. In particular brood development was evaluated, but other endpoints such as mortality, foraging activity and hive weight development were also assessed. Nine field plots at least 3 km apart were randomly assigned to receive either treatment scenario 1 (4 x 75 g a.s./ha), treatment scenario 2 (2 x 88 g a.s./ha) or control (water) applications (i.e., 3 replicates per treatment group). Two bee hives were set up per plot. Each hive contained a queen-right colony of ca. 18,000 bees. The hives were set up on the plots 2.5 weeks before the first brood assessment. Four further weekly in-field brood assessments were conducted, starting 5 days after the first application. Study duration was nine weeks.  No adverse effects were recorded during the study.  The comb area containing brood of all stages fluctuated in the control as well as in treatment groups on the different assessment days, indicating the typical natural variability of this endpoint.  No treatment-related effects on brood and colony strength were found, nor were there any treatment-related differences in mortality.  Likewise, foraging activity, nectar and pollen storage and hive weight development were unaffected in both treatment groups.  It is therefore concluded that the tested uses of spirotetramat on melons are reasonably safe to honey bees.  The results of the study reveal that replicated honey bee field studies conducted under practical agricultural conditions provide an excellent tool to reliably assess the risk of plant protection products to bees, as they provide maximum realistic insights in a holistic approach that monitors the exposed bee colonies along with all relevant environmental factors influencing its health, and are at the same time capable to overcome the natural variability of the testing system.