Global warming affects phenology and voltinism of Lobesia botrana in Spain

Climate change is promoting alterations of a very diverse nature in the life cycle of an array of insect species, including changes in phenology and voltinism. In Spain, there is observational evidence that the moth Lobesia botrana Den. & Schiff. (Lep.: Tortricidae), a key vine pest that is usually trivoltine in Mediterranean latitudes, tends to advance spring emergence, displaying a partial fourth additional flight, a fact that is potentially attributable to global warming. To verify this hypothesis, local temperatures were correlated with L. botrana phenology in six vine-growing areas of southwestern Spain during the last two decades (1984-2006) by exploiting the database of flight curves obtained with sexual pheromone traps. The dates of second and third flight peaks of the moth were calculated for each area and year and then correlated with both time (years) and local temperatures. The results obtained demonstrated a noteworthy trend towards local warming (as a result of global warming) in the last two decades, with mean increases in annual and spring temperatures of 0.9 and 3.0 degrees C, respectively. Therefore, L. botrana phenology has significantly advanced by more than 12 days. Moreover, the phenological advance contributed to increased moth voltinism in 2006 by promoting a complete fourth additional flight, a fact that has never been reported previously to our knowledge in the Iberian Peninsula. The potential impact of an earlier phenology and increased voltinism in L. botrana is discussed from an agro-ecological perspective.