In 2018, we conducted three block experiment on testing field of Biotechnical faculty. We wanted to determine efficiency of new Bt insecticide Agree WG (Bacillus thuringiensis var. aizawai) on Slovenian pesticide market. The experiment was carried out on pepper (Capsicum annum L.) plants, where we can often detect injuries caused by pests of Lepidoptera order. We had a total of three treatments, in which plants were sprayed with different insecticides (Agree WG, Lepinox plus and positive control with syntetic insecticiede Karate Zeon 5 SC) and negative control without insecticide application. Each treatment was once repeated in each block. On field we set feromone traps for monitoring season dynamic of pest poppulations: Helicoverpa armigera, Ostrinia nubilalis, Agrotis segetum and Autographa gamma. When we detected enough monitored pests or injuries, we conducted spraying. In our experiment we recorded low level of leaf and fruit injuries caused by caterpillars, which did not have effect on pepper yield. Overall, we can not give an estimate of insecticide efficiency of Agree WG for caterpillar control. At pest monitorig with feromone traps we found the highest abundance of silver Y moth (Autographa gamma) which is typical leaf pest. Average number of Y moth during all research time was 1,37 adult males per trap per day. Highest yield in tons per hectare was in negative control (11,33 t/ha), while it was the lowest (9,65 t/ha) in Lepinox plus observion.