Temporal differences in Lobesia botrana’s lifecycle at local scale, the example of the Saint Emilion vineyard

Abstract: The temporal differences in Lobesia botrana lifecycle were studied at the local scale of the Saint Emilion vineyard during the spring generation. Comparisons between sites are based on trap catches during the emergence flight thanks to a 230 classical sticky delta trap network and on head capsule width determination of the first generation larvae. 56 temperature sensors were placed next to sticky traps to explore the link between temperature and start of the emergence flight. Results demonstrated the existence of clear temporal variation in 2013, with a time lag of 34 days between extreme values at the start of the first flight. This trend was also spatially defined; its distribution being modeled by kriging. Head capsule width measures confirm the existence of temporal differences in the phenology of L. botrana in this vineyard. Although defined by a temporal pattern, the flight onset did not occur at the same degree-days between sites. This result requires further investigation but highlights the difficulty to extend modeling result obtained on a precise location to a wider scale. It permits to improve winegrower practices by scheduling insecticide spraying with better precision.