Cryptoblabes gnidiella (Lepidoptera: Pyralidae) in Southern Portugal: Underestimated pest and implications for Integrated Management

Abstract: The honeydew moth (Cryptoblabes gnidiella) is a polyphagous pest of considerable
agricultural importance, which can affect more than 80 plant species. Among these, grapevine (Vitis vinifera) is particularly notable. In Portugal, C. gnidiella is generally considered a secondary pest in vineyards, typically appearing following infestations by other pests such as mealybugs or aphids on grape clusters. During its early developmental stages, larvae feed primarily on the sugary secretions (honeydew) produced by these insects. However, in the absence of honeydew and under high larval densities, larvae can feed directly on grape berries, even when sugar levels are low. In 2023, during a Lobesia botrana monitoring in the “Península de Setúbal” wine region, significant damage linked to lepidopteran activity was observed in three vineyards. After veraison and during harvest, nests containing desiccated grapes with excrement and immature insects were observed. Insects were collected and analyzed, with the presence of C. gnidiella confirmed in the laboratory through morphological analysis (including genitalia dissection of emerged adults) and molecular methods (PCR DNA barcoding). Monitoring was conducted throughout 2024 and 2025, using pheromone-baited automated digital traps. Results revealed a massive abundance of C. gnidiella over the traditional pest L. botrana, with peak weekly captures above 2400 moths at specific sites during 2024. The findings confirm that C. gnidiella is behaving as a primary pest in the “Península de Setúbal” wine region. Consequently, current Integrated Pest Management (IPM) strategies which focus almost exclusively on L. botrana, are increasingly inadequate in the face of this new pest. This study suggests that the integration of automated monitoring and the expansion of protection windows are essential to mitigate the rising economic impact of this emerging threat.