The ovicidal and larvicidal effect of three bioinsecticides – Dipel DF, NeemAzal T/S and Tracer 480 SC against the potato tuber moth, Phthorimaea operculella Zeller (Lepidoptera: Gelechiidae) were tested under laboratory conditions. Bioinsecticides were tested at three concentrations – at the registered one for other pests in Bulgaria and at two lower ones. Only the NeemAzal T/S bioinsecticide showed strong ovicidal effect. The product in all tested concentrations had significant effects compared with the control (p≤0.05). The eggs treated with Tracer 480 SC hatched on the 24th hour after the treatment and no significant differences were observed compared with the control.
All tested products showed very good efficacy against the larvae of the P. operculella. The fastest initial larvicidal effect was registered for Tracer 480 SC, followed by NeemAzal T/C and Dipel DF. The larvae treated with Tracer 480 SC died on the following day and the efficacy reached 100% on the 3rd day after the treatment at a concentration of 0.03%. The treatments with lower concentrations of 0.025% and 0.01% reached 100% efficacy on the 5th day. The NeemAzal T/S bioinsecticide at a concentration of 0.3% showed 100% efficacy on the 7th day after the treatment. Dipel DF showed the slowest action and efficacy of 87.5% was observed on the 9th day after the treatment at a concentration of 0.15%.