Maize rough dwarf virus (MRDV) that spread by vector Laodelphax striatellus Fallen was a virus that had a latent development period of 15 to 20 d.The direct control effect for MRDV was worse,but spray key time to control vector was difficult to grasp.Seeds dressing with imidacloprid and thiamethoxam against Laodelphax striatellus was effective prevention and control technology of maize rough dwarf virus.The control effect of seed dressing with imidacloprid and thiamethoxam on Vector Laodelphax striatellus Fallen and maize rough dwarf virus(MRDV) was carried out in field.The results showed that the control effect of seed dressing to vector Laodelphax striatellus Fallen was 73190 % 83198 % and 6014% 83118 %;while the control effect to maize rough dwarf virus was 85135 % 87105 % and 84110 % 87161 % at large2bugle stage and 72115 % 73118 % and 72135 % 74134 % at harvest time with thiamethoxam at 211 218ga.i./ kg seed and imidacloprid at 218 315ga.i./ kg seed,respectively.Compared to no treatment,the yield added 36138 % 38106 %.Seed dressing with imidacloprid and thiamethoxam was no2injury to corn seed and the germinating rate was above 90 %.Seed dressing treatment with imidacloprid and thiamethoxam would delay the mean time for seed germination and seedling emergence in 1 4 d after the sowing,yet afterwards the growth speed of corn seedling was faster and the seedling was robust.Thus it can be seen that seed dressing with imidacloprid and thiamethoxam not only had effect on Vector Laodelphax striatellus Fallen,but also could prevent or alleviate MRDV occurrence and spread,and had the significant increase effect on yield.Seed dressing was one effective measure of control and prevent against MRDV.