First population quantification of the infestation of legumes by stored-product bruchids imported in freight containers into Europe.

There is a common perception that stored-product pests cause high losses only in developing countries. This may not be true because of the import of infested commodities in freight containers, especially after the ban of the broad-spectrum fumigant methyl bromide. However, infestation quantification of such infested imports has been rare in Europe because, in addition to other factors, stored-product pests have lost their quarantine status. This work documented that heavily infested commodities may be transported to Europe from a different continent (i.e., East Africa). In particular, we present the first study to quantify the entire legume-infesting pest population that may be transported in a single freight container. The quantification of the extent of adult pest infestation was performed not by taking a limited number of samples but by sieving the content of the entire container. From the analysed freight container loaded with 24 tons of infested pinto beans, 1,101,060 adult individuals of the Mexican bean weevil, Zabrotes subfasciatus (Bohemann) (Coleoptera Chrysomelidae), were extracted. This represents a density of 45.9 adults per 1 kg of imported beans. Such a huge amount of beetles per freight container holding bean commodity is 40x more than that predicted by the theoretical estimates. The visible damage to the commodity (i.e., bean kernels with physical injury and loaded with eggs) was also profound, reaching 10%; it represents 901 440 damaged kernels per container loaded with 24 t of beans. Our findings indicate that even a single freight container transporting commodities from different continents to Europe may host pest populations exceeding one million invasive pest specimens. This may have significant importance not only in terms of the hidden contamination of human food by internally feeding and allergenic pests but also in regard to the risk of spread of entire populations and different biotypes (e.g., the transfer of genes for insecticide resistance). [ABSTRACT FROM AUTHOR]