An evaluation of the effect of botanical insecticide, palizin in comparison with chemical insecticide, imidacloprid on the black citrus aphid, Toxoptera aurantii Boyer de Fonscolombe and its natural enemy, Aphidius colemani Viereck

The black citrus aphid, Toxoptera aurantii Boyer de Fonscolombe (Hemiptera: Aphididae), an important pest of citrus species, feeds by sucking sap from plant leaves. It causes some leaf distortion and malformation of growing leaves and shoot tips. In this study, the eff ects of the botanical insecticide, palizin on T. aurantii and its parasitoid, Aphidius colemani Viereck (Hymenoptera: Brachonidae) were compared with the chemical insecticide, imidacloprid. Th e compounds were evaluated at maximum recommended fi eld concentrations: palizin 2,000 ppm, imidacloprid 500 ppm, water (as control) on adult aphids. Spraying was done with a 100-l engine Honda sprayer (GX120T1, 160T1, 200T) until run-off . Th e number of dead aphids was recorded 24, 48 and 72 hours aft er treatment. According to the results, statistically signifi cant diff erences were found between treatments (p ≤ 0.05). Twenty-four hours aft er treatment, imidacloprid was more eff ective than palizin in reducing the T. aurantii population. Palizin showed high effi ciency (95% mortality) 72 hours aft er treatment. However, at that time, there was no statistically signifi cant diff erence between the mean mortality percentages of imidacloprid and palizin. This shows that botanical insecticide, palizin can eff ectively control T. aurantii. Also, palizin caused low mortality (10.86%) on A. colemani while imidacloprid was more toxic (31.1% mortality). The results of the present study indicated that palizin can be used instead of chemical insecticide, imidacloprid in control programs of T. aurantii.