Current and future perspectives on Lobesia botrana pest oviposition behavior in the context of climate change and fungicide applications

Abstract

Climate change-induced temperature increases are likely to promote the spread of insect pests into new regions, requiring adaptations in pest management strategies. Copper-based fungicides are widely used in viticulture to manage fungal diseases, but may also impact non-target insect pests. This study investigated the effects of Bordeaux mixture on the oviposition behavior and egg survival of the grapevine pest Lobesia botrana, under simulated current (2002–2021) and future (2081–2100) climatic scenarios. Laboratory choice and no-choice experiments were conducted to assess oviposition preferences, potential deterrent effects of Bordeaux mixture, and its toxicity to eggs. In the choice experiment, L. botrana females showed significant preference for untreated grapes under both climatic conditions. However, in the no-choice experiment, Bordeaux mixture neither significantly deterred oviposition nor affected egg hatching rate in either scenario. While Bordeaux mixture had minimal influence on oviposition behavior, future climatic conditions significantly reduced female longevity and fecundity. This reduction in reproductive output may suggest lower pest pressure, but accelerated generation turnover and increased voltinism under warmer conditions could amplify pest pressure in the long term. This study provides insights on the collateral effects of Bordeaux mixture on L. botrana under a future climatic scenario and emphasizes the need for further research on its potential impacts on other key life history traits (e.g., development, reproduction). These findings highlight the importance of integrating climate change projections into pest management strategies to ensure sustainable viticultural practices.