Stored products insects in Portugal – New data and overview

Abstract

The introduction of stored product insect pests to new areas is facilitated by food trade among countries, and effective detection and monitoring programs are crucial for food security. The khapra beetle, Trogoderma granarium Everts is one of the most destructive insect species. In Portugal, T. granarium has been detected in 1988. However, no new data has been added to this information since that date. Floor traps with pheromones specific to T. granarium were used and placed inside ports, mills, and storage facilities, including warehouses and silos, between June and September in 2017, 2019, 2021, and 2022.Previous results from other sampling programs conducted between 2002 and 2008 are also referred here to add more evidence for the presence or absence of T. granarium in Portugal. Here, various types of traps, including some generalists and others with pheromones (such as T. granarium), were used. The collected insects were identified to species, or genus.Surveys conducted identified approximately 40 insect species that are associated with stored products, in a total of 23.725 insects, and among them, the weevils belonging to the genus Sitophilus C.J.Schoenherr have been recognized as the main pests that affects stored cereals. Regarding the surveys made between 2017 and 2022 and previous surveys done in Portugal (between 2002 and 2008; n = 26.719 insects identified), no T. granarium individuals were detected in any of the entomological samples, and only a few Dermestidae specimens were found across all surveys, one of them belonging to the same genus, identified as Trogoderma inclusum LeConte. With the predicted changes in climate, there is a risk of introducing T. granarium and other destructive insect pests that could displace Sitophilus weevils as the key stored products pest in Portugal. Therefore, it is crucial to monitor and implement measures to prevent the spread of invasive pests for effective pest management and food security purposes, using proper trapping methods and accurate and rapid identification tools.