The aim of the research was to determine the efficacy of botanical insecticides in form of powder and extract, inert dusts and combination of botanical insecticides and inert dusts in control of three stored-product insects: Rhyzopertha dominica (Fab.), Sitophilus oryzae (L.) i Tribolium castaneum (Herbst). The research was carried out in laboratory conditions through a series of experiments in glass containers filled with wheat and application on various surfaces. Nine plant species were tested as powders and extracts and also six inert dusts of Croatian origin as well as diatomaceous earth Celatom Mn-51®. The insecticidal effect depended on type of treatment, dose, exposure and insect species. Tested plant powders on wheat indicate that satisfactory mortality (91.0%) was achieved only against R. dominica with lavandin at a dose of 8,000 mg kg-1. Application of plant extracts on glass surface reached the highest mortality of all insect species. Results of tested inert dusts showed that the highest mortality (90.0%) of R. dominica was achieved with Celatom Mn-51® as well as the highest inhibition of progeny (99.19%), while maximum mortality of S. oryzae was achieved with inert dusts D-01, MA-4 and Celatom Mn-51®, which also achieved a complete progeny inhibition. Maximum mortality of T. castaneum was achieved with Celatom Mn-51® and a complete progeny inhibition was achieved with inert dusts D-01, MA-4 and Celatom Mn-51®. Significant reduction of test weight was observed at the highest LD90 doses in treatments Celatom Mn-51® and inert dusts PD-1 and MR-10. Results of tested mixture of plant powder and inert dust indicate that the highest mortality (68.0%) of R. dominica was achieved with combination of Celatom Mn-51® and lavandin at a 1:15 ratio and in the same treatment the highest progeny inhibition (93.83%) was also achieved. Testing of mixture of plant extracts and inert dusts indicate that only the combination of inert dust MA-4 and poppy at a 1:10 ratio has achieved a higher mortality of T. castaneum compared to inert dusts applied alone. This doctoral dissertation was funded by the Croatian Science Foundation under the project IP-11-2013-5570.