The effect of botanical insecticides of pepper and garlic extracts in combination with soap spray on the elm leaf beetle, Xanthogaleruca luteola Mull. under field conditions

The elm leaf beetle, Xanthogaleruca luteola Mull. (Col.: Chrysomelidae) is one of the most important pests of elm trees in the green urban landscape. According to multiple hazards of chemical insecticides and environmental importance of urban green space, in this study, the effect of botanical insecticides of pepper extract (Tondexir®)andgarlic extract (Sirinol®) in combination with soap spray (Bartar®) at two spray stages were investigated against X. luteola larvae. A randomized complete blocks design with 5 replications was performed as experimental design. The trials were carried out with recommended concentration of each compound. The sampling was carried out on the day before treatment and 2, 7, 14 and 21 days after treatment. The results showed the highest and lowest population reduction percentage of larvae as recorded at tondexir + sirinol (78/56 and 64/99%) and tondexir (41/4 and 23.06%) treatments, at 2 and 21 days after treatment, respectively. The results indicated that sirinol was more effective (15-17%) than tondexir to control X. luteola. Bartar spray soap increased the efficiency of the botanical insecticides of tondexir and sirinol, to 6-18 and 4-28%, respectively, at different post-treatment days. As a result, bartar spray soap showed synergistic effect on these botanical insecticides. Therefore, with respect to the results of this study, these botanical insecticides can be used as safe and suitable compounds in integrated control management of X. luteola in the urban greenlandscape.