9. Efficacy of Citromazinc for the biological control of the Aphis spiraecola Patch (Hemiptera: Aphididae) on apple trees in Bulgaria under laboratory and field conditions

The invasive Aphis spiraecola Patch, which originated in Eastern Asia, recently became a common pest on apple in Bulgaria. The aim of the study was to determine the efficacy of the biological insecticide Citromazinc in concentrations of 0.15% and 0.3% under laboratory and field conditions, against the green citrus aphid (Aphis spiraecola) on apple. Citromazinc is a corrector of manganese and zinc deficiency, which are essential for the formation of chlorophyll. Manganese also acts as a catalyst in many enzymatic processes. Zinc acts as an activator of some important functions and participates in the formation of auxins and growth hormones. Citromazinc showed excellent biological efficacy against the green citrus aphid under laboratory conditions. In both applied concentrations (0.15% and 0.3%), the efficacy reached 100% on the 7^th day after treatment. The effect of the product was also very good under field conditions. On the 7^th day after treatment, the efficacy reached almost 100% in the higher concentration (0.3%) and 90% in the lower concentration (0.15%). The tested biological insecticide Citromazinc is suitable for the efficient control of the green citrus aphid in apple orchards, even at its lower applied concentration.

Keywords: Green citrus aphid, biological efficacy, insecticide, apple