3-aryl pyridazinone, preparation method, pesticide composition and use

Provided are 3-aryl pyridazinone as shown by formula I, and a preparation method, pesticide composition and use. The 3-aryl pyridazinone provided has a highly-efficient herbicidal activity, a relatively broad phytocidal range, good crop safety, a relatively wide drug application period, and a short residual life in the soil; the 3-aryl pyridazinone exhibits good pre-emergence and post-emergence herbicidal activity at low doses, has control effects on all of farmland broadleaved weeds, farmland gramineae weeds and Cyperaceae weeds, and has a certain safety for crops such as corn, rice, wheat, cotton and soybeans at high doses; the 3-aryl pyridazinone can effectively inhibit the germination of weeds, and at the same time has a good herbicidal activity on 3-6 leaf-stage sensitive large weeds and no harmful effects on the growth of succeeding crops; and the 3-aryl pyridazinone has a reasonable toxicity, ecotoxicity and environmental capability, belonging to environmentally friendly low-toxic pesticides with good market prospects.