Opportunities for Control of the Rose Stem Girdler in Organic Oil-bearing Rose Production

The rose stem girdler has been identified as the primary economic pest affecting oil-bearing rose plants. A mass attack can reduce the yield of rose flowers by up to 40%. The current study examines the effectiveness of three organic pesticides on the Agrilus cuprescens population. The field experiment was conducted in the village of Kliment, located in Bulgaria's Rose Valley, using a five-year-old organic rose plantation. The following products have been included in the investigation: Limocide® (60 g/L orange oil), NeemAzal® T/C (2.5% Neem substance), and a 4% bee glue solution applied individually and in the following combinations: Limocide® + 4% bee glue solution, and NeemAzal® T/C + 4% bee glue solution. These products were sprayed twice before flowering in an interval of 10 days and once in the postharvest period. The study was designed using a randomized block method with four replications, and each plot had a size of 18 m², containing 21 plants per variant. During the testing period, the combined treatment with Limocide® and propolis solution showed the highest effectiveness, managing to reduce the population of adult insects by up to 83%. When applied individually, Limocide® demonstrates 72% effectiveness against the pest, followed by the standalone application of propolis solution with an effectiveness of 64%. Moreover, the product Limocide® was able to reduce the formation of new galls by up to 92%. More research is needed to investigate the exact mechanism of action of orange oil and propolis extract at different stages of the enemy's development.