Toxicity efficiency of microencapsulated concentrate of Egyptian blue silk on Chaitophorus niger Mordvilko and Oenopia conglobata L.

The black willow aphid, Chaitophorus niger Mordvilko, is a pest of willow trees in the green space, whose activity weakens the trees as well as secreting honeydew during the spring and summer. The predatory ladybug, Oenopia conglobata L. (Col.:Coccinellidae), is one of the most common predators of aphids. In this study, the pupal stage of the ladybug was collected from the municipal parks (Sabzeh, Salamat) and was reared in the Plant protection laboratory of the Green Space Education and Consulting Research Center of Tehran Municipality, District 17. Homogenization of second instar and adults of aphid was performed in vitro conditions (15-30 °C, relative humidity 65 ± 5%, photoperiod 16: 8 L: D). Then, the micro-emulsion contact toxicity effect of aqueous extract of Caesalpinia gilliesii (fruit; seed) prepared from the pesticide research department of the Iranian Plant Protection Research Institute, was determined on the nymphs and adults of willow black aphid and Oenopia adult by foliar application with LC50 determination in vitro. Bioassay was carried out in 24, 48 and 72 hours in a completely randomized full factorial design with four replications of C. gilliesii (1000, 2000, 3000, 4000 and 5000 ppm) and diazinon (1000-2000 ppm).The results were statistically analyzed using Design Expert 12 software. The lowest mortality was observed in nymphs and adult aphids after 24 hours at a concentration of 1000ppm with an average of 33.3% and 16.6% respectively in Egyptian silk. However, the highest mortality was observed at the concentration of 5oooppm of Egyptian silk, which was not significantly different with 2000 ppm diazinon. The average mortality of ladybugs in 72 hours after the experiment was 1.6% in 1000ppm of Egyptian silk extract, while the highest mortality was observed at 5000 ppm of this extract in 72 hours after the experiment (21.6%). According to the results, the highest aphid mortality in the plant formulation was related to the concentration of 5000 ppm. Therefore, the formulated composition of Egyptian silk can be improved by slightly changing the formulation process to reduce the consumption concentration, and this new combination can be used for sustainable urban management in pest control and maintaining environmental health.