Disturbing the conditions in the warehouse, storage mass is exposed to infestation from various pests, viruses, bacteria, and there is a risk of permanent violation of the quality of stored food, as well as the possibility of huge economic losses. With increasing awareness of environmental protection, there are natural ways of preserving storage space and using the potencial of natural plant materials. Using inert powders and essential oils of plants helps reduce the use of conventional preparations. The use of these preparations is safe, especially for people, it provides long - term protection and it doesn't distort the quality and value of product. This paper describes the laboratory testing of the effectiveness of lavender (Lavandula x intermedia), in powder form of a flower with a leaf and stem powder, essential oil and powder mixture of lavender flower and leaf with diatomaceous earth in the suppression of lesser grain borer Rhyzopertha dominica (F.), rice weevil Sitophilus oryzae (L.) and red flour beetle Tribolium castaneum (Herbst) in stored wheat. The test results show that the maximum mortality and fastest action is accomplished with usage of the essential oil of the lavender. Lower mortality was achieved with a mixture of flower powder with diatomaceous earth, while the effect of lavender powder marginally affected on the mortality of the tested species of harmful insects. Lavender (Lavandula x intermedia) showed potential whose essential oil and flower powder mixed with diatomaceous earth can be used to develop new formulations of natural insecticides which would be able to find application in the protection of stored products.