The current study was conducted to investigate strength and durability of the effect of three widely used insecticides against mango leafhopper (MLH), Idioscopus clypealis (Lethierry) (Hemiptera: Cicadellidae) in two different methods (foliar spray and trunk injection) in Roodan district (Hormozgan province). The study was performed as factorial arranged in a Randomized Complete Block design (RCB). In all sampling sessions (3, 7, 15 and 30 d post applications), the number of nymphs decreased significantly on the inflorescence, indicating insecticides used in both methods were able to suppress MLH, relatively. Although the insecticides showed no significant difference in foliar application, they were significantly different when injected through the trunk (F=8.85; df=2; P<0.01). Also, significant difference was found among different sampling times (F = 85.0; df = 3; P<0.01). By comparing various sampling sessions, the highest mortality rate was observed at day 30 (74.8 ± 2.31%) and the lowest ones occurred on day 3 (23.9 ± 4.06%). Over time, the percent of the insect mortality increased. The highest rate of mortality was observed in Dimetoat through injection method (57.2 ± 5.89%) and the lowest occurred in Acetamiprid by the same method (33.8 ± 7.37%). By these results and considering high susceptibility of mango to foliar application of chemicals at flowering stage, trunk injection of appropriate pesticides can be a promising approach to suppress MLH and probably other common mango pests present and damage at that stage like gall midge.