In 2021, we conducted a field experiment, where we wanted to examine the use of four crops (sunflower, soybean, alfalfa and sorghum) as a method of attracting the brown marmorated stink bug (Halyomorpha halys [Stål]). We also studied the efficacy of three bio insecticides (Botanigard WP, Nemaplus® and NeemAzal – T/S ) on the proposed crops against H. halys. Two of the three bio insecticides that we used were based on biological control agents (Beauveria bassiana and Steinernema feltiae) and the third was of plant origin, based on azadirachtin (Azadirachta indica). We also determined a negative control (no insecticide application) and a positive control (Karate Zeon 5 CS application) for the purpose of verification of the selected bio insecticides. The experiment was set up next to an apple orchard in Miren, located in the Primorska region of Slovenia. We divided the experiment into two segments, so that the first part, which was intended only for incidence assessment of the pest, was separated from the second part that served to evaluate the effectiveness of the selected bio insecticides. The occurrence of the pest was assessed by it's developmental stages, both on trap crops and apple trees at 10-day intervals. At the same time we also recorded the phenophases of each trap crop. The studied bio insecticides were applied on the trap crops at 10-day intervals. The occurrence of the pest on the treated crops was assessed before and after insecticide application. During the period of the study the highest average number of H. halys was recorded on the primary host plant, apple trees. Sorghum was the most effective in attracting H. halys among the selected trap crops, followed by sunflower, soybean and alfalfa. We also discovered that the occurrence of the pest is realted to the phenophase of the crop. An increase of the pest was recorded when most crops entered the growth stage of the development of the fruit. We also found that Nemaplus®, Botanigard WP and NeemAzal – T/S had no effect on the pest and had no affect on the occurence of H. halys (same averages as in the negative control). The only significantly low average number of stink bugs was recorded on the positive control treatment.
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