Insect pest susceptibility of grains and seeds recently introduced to the Italian market: An experimental evaluation

To assess the susceptibility of pseudocereals (amaranth and quinoa), minor cereals (teff and millet), and oilseeds (chia and hemp), now commercially available on the European market, to attacks by polyphagous and cosmopolitan insect pests, laboratory tests were set up. Tests involving controlled infestation of seeds, using laboratory-bred insects (Tenebrio molitor, Tribolium confusum, Oryzaephilus surinamensis, Cryptolestes pusillus and Plodia interpunctella), were carried out in a climatic chamber at 23 ± 2 °C and 65 ± 5% R.H.. Development time, the number of adults and the weight of these adults were evaluated. The results show that each considered foodstuff has a different susceptibility to infestation and differences both in the number of adults emerged and in their weight compared to control. Millet was the only product that allowed larval development up to the adult stage for all the species examined. No species developed on amaranth. T. confusum and O. surinamensis reached the adult stage on the greatest number of products, 5 and 4 respectively; C. pusillus and T. molitor completed their life cycles on only two commodities: millet and teff, while P. interpunctella only on millet and hemp seeds. Considering the impact of the different pests on the studied grains, T. confusum was the only species able to develop on all the grains, but the number of emerged adults was lower than on the standard diet. These results show that, even if these commodities are new in the European market, they are susceptible to the infestation of common stored product pests that could led to a removal from the market of a contaminated stock, so a continuous monitoring is needed.