Effect of propolis extract (bee glue) on Tetranychus urticae Koch (Acari: Tetranychidae) under greenhouse conditions

The pesticide efficacy of propolis (a bee-hive product) was studied on the different stages of the two-spotted spider mite, Tetranychus urticae, under greenhouse conditions. Five concentrations of ethanolic extract of propolis 250, 500, 1000, 1500, 2000 ppm and the control were used in bioassay experiments. Results showed highly significant differences between mortality percentages at all concentrations. The mortality percentage at concentration 250 ppm was calculated for all stages (egg, larva, nymph and adult) after 24 hours which recorded 41.21 ± 0.54, 19.47 ± 0.82, 20.83 ± 0.60, and 44.35 ± 0.47 %, respectively. While the mortality percentages at concentration 250 ppm after 48h for egg, larva, and nymph stages of T. urticae were 62.05 ± 0.16, 50.18 ± 0.28, and 56.03 ± 0.28 %. The high mortality percentage was observed after 72h of treatment of all concentrations and all stages. At concentrations of 1500 and 2000 ppm, the mortality percentage reached its maximum in immature stages, which recorded 95.67 ± 0.47 % in the egg stage. Both larva and nymph stages were 93.86 ± 0.28 and 93.36 ± 0.35% at concentration 1500 ppm. Meanwhile, the concentration of 2000 ppm, the mortality rate was 98.27 ± 0.57% for eggs and 98.25 ± 0.37 and 97.42 ± 0.39% for larva and nymph stages in comparing with the control. Our findings showed that the average value of total phenolic content was 2494.4 µg gallic acid equivalents (GAE)/g ethanolic bee glue (propolis) extract. The antioxidant activity was determined using DPPH (2, 2-diphenyl-1-picrylhydrazyl) assay using ascorbic acid as a standard antioxidant. The obtained results exhibited that the ethanolic extract of propolis has a higher scavenging activity (92.99 %) than that of ascorbic acid (87.32 %) at 30 μg/mL.