Influence of Chemical Composition and Degree of Fragmentation of Millet Grain on Confused Flour Beetle (Tribolium confusum Duv.) Infestation

Abstract

Owing to its wealth of nutritional values and low cultivation requirements, millet can become a key crop in global food systems. Thus, the Food and Agriculture Organization (FAO) declared that 2023 is the International Year of Millet. The introduction of this cereal and its products into universal food circulation calls for a multidimensional approach, which would also consider threats posed by pests during the storage of cereal kernels. The aim of this study was to evaluate the development of the confused flour beetle (Tribolium confusum Duv.) on common millet (Panicum miliaceum L.) and products obtained from this cereal, and to analyze the factors which influence its development (chemical composition of kernels, degree of their fragmentation). The study was conducted under laboratory conditions in an environmental test chamber (temperature 30 °C, humidity 70%, light—complete darkness). Millet grains of the Jagna cultivar and its products were weighed at 20 g, placed in vinidur dishes, and 10 beetles were then placed on the prepared material. The experiment demonstrated that the millet grain and food products obtained from this grain (millet flour, flakes, groats) could be a suitable habitat for the development of the confused flour beetle. The key regulator for the development of this pest insect is the degree of fragmentation of the infested material. The millet grain and millet products (except millet flour) are characterized by less numerous developments of beetle progeny than wheat products, which could be another advantage of millet in an integrated international system of grain storage. Chemical analysis also showed a significant correlation between the abundance of offspring generation and the content of crude fat (especially linoleic acid—C 18:2). Knowledge of the resistance or susceptibility of millet to storage pests may be useful in implementing integrated principles of protection of stored products against pests.