Application of the flour of four leguminous crops for the control of tenebrionidae beetle (Tribolium castaneum - Herbst)

Abstract

Provender used to breed animals is constituted mainly of cereal flour. However, due to poor post-harvest technologies, more than 35% of annual crop yield is often lost during storage as a consequence of insect attack. While synthetic insecticides constitute an efficient method for reducing these losses; current excessive usage runs the risk of increasing the food insecurity. The use of entomotoxic proteins of leguminous plant for grain storage has been advocated as an alternative method with limited or no effect on the quality and safety of the grains or their products. This study
was carried out as an evidence of bioactivity of four flours of seeds of Phaseolus vulgaris, Pisum sativum and two varieties of Glycine max (SJ320 and DOCKO) against adults of Tribolium castaneum Herbst which is a very resistant stored product pest to chemicals in Northern Cameroon. The growth of ten couples of T. castaneum in different formulations made by the mixture of sorghum flours with leguminous seed flours is evaluated 50 days after application. The research carried out reveals that the population of T. castaneum is important in the soybean formulations. In the pots
of bean and pea flours, the average numbers of living pests were  respectively 21.17±10.5 and 32.38±18.3 against 65.99±28.1 and 95.2±36.7 for the pots containing soybean SJ320 and DOCKO flours, respectively. In treatments PP20 and BB20, the number of nymphs 82.4±6.7, 86.6±2.7, respectively and the larvae V 22.2±9.9, 68.8±8.9 in that order decreases comparatively to the control 143.6±7.4, 142±12.5,
respectively. The incorporation of these promising flours of pea and bean at a rate of 20% during manufacturer of provender used to feed animals can contribute to their better cereal food conservation and can reduce the residues of chemical pesticides in the environment. The formulation with 20% of black beans or pea flours in sorghum flour ensures an effective control of T. castaneum. The development of a bio insecticide made of flour of pea or black bean is to be considered seriously since their residues are not poisonous to consumers. Cereals which are important and indispensable for the production of animal feed can be preserved from insect attack by the use of natural products, which will contribute to diminish the toxicity of chemical preservatives used in feed, environmental pollution and the phenomenon of resistance of insects to chemical pesticides.

Key words: Entomotoxic proteins, Tribolium castaneum, Stored, Provender